Mechanical – Chamber of Understanding

RX8 Project – Part 22, Engine Rebuild

To preface this I am not an engine builder, this is just the approximate process I followed more to give you all some handy reference photos and some info that might be helpful to someone. Please don’t take any of this as gospel! I still don’t even know if the engine will actually work!

Anyone reading this blog may have noticed that the mechanical work on the car seemed to stop a very long time ago. While there has been a bit of a gap due to other aspects of life getting in the way there was more progress than it may have appeared. Back in 2018, some 3 years ago as I type this, I took my recently stripped engine parts (ostensibly the block and crank) along with the custom flywheel and spacer to be checked and relevant parts balanced with a view to rebuilding the engine.

With little surprise I got a call back shortly after to tell me the pistons were not serviceable and would need replacing. Following my earlier research (mentioned in a previous post) into the Noble M12 and later cars I decided that for the power point I was aiming for (300 bhp approximately) the stock cast type pistons should be up to the job with Noble moving over to forged parts with the M400 model and target power above 400 bhp. Online I’ve seen many people reporting the cast pistons hitting their limits up around 500bhp but what their life expectancy is at that point who knows. With some luck I manged to find a set of +0.5mm oversize stock replacement pistons online ( part H663CP ) so sent these up to be checked for balance with the engine. The thing Noble did upgrade was to upgrade the factory rods with forged ones so I had already sourced some suitable rods although even that was a bit of a challenge. The ones I bought were from XPOWER Engines in Essex and are still listed on Ebay as I type this as ST220 3.0 H-section EN24 steel rods and come with ARP 2000 bolts. I’d not come across this company until this point but some research showed they are quite well known so I felt pretty confident they’d be ok.

So now I’ve got these parts all shipped up to MJA Automotive in Bromsgrove who would rebore and hone the block to match the new oversize pistons as well as giving everything a proper clean, checked and completely balanced. They’re a small firm but attention to detail was great, they even sand blasted and repainted the original crank pully because it was a bit rusty.

So now I had a pile of goodies to put together :

This picture is another good indication of how small this engine block actually is for the potential power output. You can see all the goodies here and basically everything that should be replaced was so new pistons, rings, rods, clutch, upgraded engine bearings (more on this later) and then obviously the custom flywheel and cleaned crank. This means only one thing, I had to build up the engine. Now when most people rebuild their own engine for the first time they start with something like a lawnmower engine but not me…In retrospect I probably should’ve just paid MJA to build it but I like a challenge!

First things first I decided to assemble all the pistons on the rods to have a quick win. This is as simple as taking the ring clip and pin out of the piston, putting the rod in place, sliding the pin back through and putting the ring clip back in. Add a dab of lubricant inside the small bearing before you put it together. The pin should be a slip fit on this because its a fully floating arrangement and so the rod bushing may need reaming to fit correctly if this isn’t the case. It’s also with noting these rods are not handed because in this engine they all have individual locations on the crank and do not touch each other whereas some engines have paired locations leading to the rod big end bearing having a flat side and a curved/chamfered side on the outer faces. If you see this the flat faces of the rods should be oriented to touch each other in the pair.

Comparison of used stock piston and rod and new piston and forged rod

Here you can see the state of the old pistons and the massive difference in the size of the rods. The keen eyed amongst you may notice this piston has the rings installed, what I actually did was installed all the oil rings at the bottom of the pistons but left the compression rings of so they could be correctly trimmed and fitted to the engine later. The ones show I’d slotted on for my own curiosity about how it all went together and removed shortly afterwards.

Box of assembled pistons and forged rods for S-type v6

That all looks rather shiny, I’m not used to car parts being this clean!

This was around the time I tried to find a manual for how to actually rebuild this engine with all the tolerances allowed for all the various parts and after a brief search found the S-type workshop manual located on jagrepair.com . This manual is massive at some 3300 pages and covers basically every aspect of the car but obviously since I don’t have the rest of the car I concentrated on the engine section which for this engine starts on page 635. I can’t add much on the instruction in it – it really is step by step so that’s the place to go for the detail!

So back to the things I did differently and some gratuitous photos of shiny stuff. while We’re still on the subject of piston rods I actually found and ordered some Mahle motorsport “high performance” racing bearings but curiously I found out shortly afterwards that Mahle Motorsport don’t sell a kit for this engine. After a concerning period waiting to see what would turn up and if I’d just been conned what actually arrived was the following :

Checking the Mahle racing bearings catalogue I’d already found told me this was actually a bearing for a 2.3L Duratec which is a 4 cylinder engine and I’d been shipped one complete 4 cyl bearing kit ( kit number VC1013) and half a second one to make up a complete set for the V6. Checking it all out sure enough they do seem to be the correct dimensions for this engine.

Rod bearing installation detail for S-type V6

They fit well but the only bit of strangeness is racing bearings don’t have the location notch usually found on rod bearings so a lot of care must be taken to make sure they’re correctly centred in the rod when it’s assembled. Apparently this is because the notch reduces the bearing area adjacent to the notch. More info about this can be found from Mahle themselves here . Contrary to common belief the notch isn’t there to prevent the bearing from spinning and is purely to centre it on assembly. Once the rod is assembled the the hoop stress in the bearing produces so much friction it will stay in place with no issues. Spun bearings are caused when the bearing seizes onto the crank, this is usually caused by insufficient lubrication and if this happens the bearing will spin whether or not you have the notch.

So back to the block, once it’s mounted upside down on the stand go ahead and drop the block side halves of the crank bearings in place. The parts I used here are King bearings kit number MB4056SI :

Crank bearing installation photo for S-type V6

Crank bearing photo at an angle, S-type v6

Also don’t forget to add the thrust bearing on the flywheel end. It’s a bit hard to see in the photo because I haven’t got a photo without assembly lubricant but it’s there.

Apply assembly lubricant to all the bearing faces

Now drop in the crank, carefully! then go ahead and apply assembly lubricant to all the running surfaces. In the photo the middle two rod locations aren’t lubricated yet because they’re at the back and needs rotating for access.

Next take the lower block housing and install the other bearing halves into the appropriate locations. As above apply assembly lubricant on the bearing faces.

Check the bearings are holding on as the next step involves dropping this section downward onto the upper block so make sure they don’t fall out. If they wont stay put you can lift the crank back out, drop it on this section then use it to hold the bearing shells in place when you flip it over and put it on the upper block. Run a bead of RTV along the mating face of one the two block halves before you put it together. Read the instructions on the RTV – usually you need to let it partly cure before pushing the parts together. Remember the RTV goes to the inside of the bolt holes otherwise oil will weep past the bolts. This is also why the flange is wider on the inside.

Hopefully you should have something that looks like this. Note the locations of the bolts with the M6 thread on the reverse side – these are the ones the the windage tray bolts onto so they have to be in the right positions. Torque all the bolts down following the workshop manual.

Now for the top side. We need to set the piston ring gaps which will involve working out what your gap should be (there are various online calculators now which make this easy). We need to be looking at larger gaps due to running a turbo and I wanted to make sure I had some headroom to run higher boost later without issues so worked on the side of going a touch larger. I ended up with a number of 0.57mm on the top ring and 0.72mm on the second ring but I think this is probably overly cautious. Who knows, maybe one day I’ll run nitrous. The rings are measured by inserting them into the bore, making sure they’re totally parallel to the block deck using some sort of depth tool, this can be done with a vernier caliper or a variety of other methods. You then measure the gap with feeler gauges when in this position and file back the ends of the ring as necessary to get the required gap. The filed ends need to be totally flat and parallel to each other. I put a flat file in a vice and carefully filed it down. Be careful, you can’t put it back if you go too far. Also piston rings are very brittle. Don’t mix up your top and second rings of install them wrong. I suggest buying a cheap piston ring installer plier to get them on easily.

It’s quite common to lubricate the cylinder walls prior to installing the pistons but some ring manufacturers actually specify not to do this now. Check the instructions on your rings. I used a light coat of some slightly thicker engine oil I had lying about and wiped it off with a rag. The general guidance here is assembly lubricant shouldn’t be used on cylinder walls as it prevents the rings bedding in correctly.

Next up you need a piston ring compressor to tighten up the rings to fit into the cylinder bore. Make sure you get this tight enough because why you try to tap the piston into place if the ring is sticking out relative to the bore it’s possible to break the ring. Traditionally people drive the piston in with the wooden handle of a hammer to avoid damaging the piston face. I came up with a different solution tapping a section of silicone hose to avoid damage. Be careful to line the piston up with the bore. If you can rotate you engine stand such that the piston you are trying to put in is vertical then do so, this way you are less likely to scratch the bore with the rod as you lower it in.

Using a section of hose to install pistons

The pistons should have an indication mark on it which shows which side should point to the front of the engine. In this case this is the drilled mark but on other pistons it can be an arrow on the piston face or other mark, make sure you get this right!

Once the piston is fully in the bore go underneath and carefully guide the rod onto the crank then bolt the end of the rod back on (with its bearing inside) and do up the bolts. At this point they only need to be tight enough to stop it all falling apart so even finger tight is probably enough or a little over.

Now that’s quite shiny!

One question that comes up all the time is the correct socket for ARP rod bolts. after a lot of searching I’ve found according to their catalogue they do them with two common sizes of head, either a 3/8″ AF or a 7/16″ AF, both of which are of 12 point type so standard 6 point sockets will not fit. I’ve seen numerous reports online where people are saying it’s a 10mm metric. It isn’t, a 12 point 10mm will fit over the 3/8″ head but it’s a very sloppy fit you’d be only contacting the bolt on the very top of the points making the risk of stripping the head quite high. The correct socket should be a very nice slip fit.

I’m not sure exactly which kit the rod bolts are from (or even if they are from one) because they came assembled into the rods to keep them together. ARP themselves don’t seem to to a specific kit for this engine so I would assume much like the rod bearings (which I bought from the same company) they’re actually repurposed parts from the Duratec 2.3 kits or something similar. With the forged rods they could be almost be anything just selected to fit the rod so I suggest either buying them with the rods or you can buy ARP bolts by thread and length to suit whatever you have.

Once you’ve put all your pistons in and torqued all the bolts up we move on to new head gaskets. First of check where the location sleeves are – as you look at the mating faces of the block two of the holes are larger, these are intended to have steel sleeves in which locate the head relative to the block. I installed these in the block but if you do the next few steps the same as me you might find it easier to install these into the head to make the assembly easier. The head gaskets I used were genuine Ford originals parts (actually badged FoMoCo) but sold as Jaguar parts they are specific to this version of the engine because the Ford version of the engine has different water flow routes open/blocked to make the coolant flow differently. The parts I used are as follows :

RH Head Gasket 2.5 Jaguar – C2S44649
LH Head Gasket 2.5 Jaguar – XR857984
Head Bolts (Single) – XR85387

You might want to order an ARP head stud kit at this point rather than the standard head bolts. I didn’t as at the time it was an expensive add-on (around £300) for what was supposed to be a budget project but in retrospect it might have been a safer option. I don’t have the part number for the kit noted anywhere.

Bolt on the water pipe pipe on the top front of the block at this point. It’s much easier than doing it later! Don’t forget to install the O-ring on it and for belt and braces it might be best to add some RTV round it because fixing it if it leaks is a big job involving removing at least one head.

Now the next bit is something people will probably hate me for but whatever, as I’ve said before this was supposed to be a budget build with the potential for later upgrade if it ever worked. What I did was get a decompression plate cut to space out each cylinder head a little because these engines are 10.3:1 as standard and I wanted to run a not insignificant amount of boost through it. Because my plan was to have the best response I could from the engine I still wanted to keep the CR as high as I could while having a safe enough margin after a discussion with Mike at Ferriday Engineering. While I write this in 2021 his website is giving me a security warning so I don’t know what’s going on there but his email is mike@ferriday.co.uk, I can only assume (and hope) he’s still operating because he’s a very nice and knowledgeable guy. He told me that standard 1.5mm plate would give a compression ratio of 9.1:1 which should be fine. We started under the assumption the mating face would be the same as the Mondeo V6 he already had on file but that turned out to not be the case and he ended up taking my old gaskets as a template and then during a couple revisions by email I highlighted some holes that didn’t exist in the head so could safely be taken out of the decompression plate.

The decompression plate gets bonded to the face of the heads and effectively forms an extension of it, there are a few sealers used for this but the most widely regarded of them seems to be Stag Wellseal which is a form of high temperature non setting sealer resistant to fuels and oils. It is initially quite liquid but goes very sticky rather quickly and after that its quite challenging to remove. Get a suitable plastic spreader and move quickly! Despite various tales on the internet of people using the plate with two head gaskets (one each side) that’s not how these are supposed to be used generally. The idea is the face of the head is freshly refinished and so is totally smooth and flat and the decomp plate will be the same so the actual thickness of sealer will be negligible. Add to this the plate, head and block are all aluminium and so there shouldn’t be any differential thermal expansion issues. So yes it’s technically a bit of a bodge, but it’s done in the best way we can and by all accounts should hold up to my use without issue. Plus I always have the option to get custom forged pistons made later if I want to throw lots of money at it. At the end of the day this is still a cheap engine so if it does all go wrong I’ll do something else!

S-type v6 with decompression plate test fitted

Here you can see the decomp plate in position for a trial fit before being bonded onto the head. If you look carefully you’ll notice the cylinder bores in the plate aren’t round, this is because they’re not actually round in the head gasket to provide clearance for the valves.

Its probably worth highlighting here that on this engine the head bolts are under the cams so you have to assemble the head after bolting it in place. The head bolts are M10 with 6 point hex heads but with a reduced size hex. They are recessed in narrow deep bores, I used a standard 15mm deep impact socket but it was very close to not fitting so worth checking this though if yours doesn’t fit you probably found out when you took it apart!

The head bolt tightening sequence and procedure are detailed in the workshop manual but long story short I suggest getting an angle gauge for this as they’re specified as a torque + angle. These are torque to yield bolts and so you get one shot to get it right since they’re single use.

Once the head is bolted down install the cams. At this point is doesn’t matter where in their rotation they are as we will set that later but try to put all the cam retainer pack in the same positions they came out of. Make sure to coat all bearing/contact surfaces with assembly grease.

Next if you are re-using the S-Type water fitting on this engine (though I think this applies to others as well) you will want to install this now if you haven’t already, if you don’t you won’t be able to with both heads bolted on so this is your last chance!

Now just rinse and repeat for the other head…

Once you’ve done that slip the oil pump onto the crank and bolt it in place. Hopefully at this point you should have an engine that looks a bit like this:

S-type v6 front of engine (no cover) with both heads in place

If you’ve got to this point I suggest going and having a break. This assembly will be continued in my next post…

Living with a Scirocco 1.4 TSI 160 (118kW) – Part 3, Supercharger Bypass Valve (P10A4 Fault)

Sometime last year I was having problems finding a spot in a carpark so ended up sat in the car with it idling for several minutes and when I went to pull away the engine warning light flashed on almost immediately – not something anyone wants to see!

For the rest of the drive the car would mostly work ok at low engine RPM but the engine all but refused to go above approximately 3000rpm which is around the RPM the turbo takes over from the supercharger on this engine and the supercharger is disengaged by its electronic clutch. The curious bit was that at hitting the cut off there was a sudden loss of power at that RPM rather than it staying consistent and just holding an RPM limit suggesting it wasn’t a limp mode as such. My initial suspicion was that the turbo wasn’t spooling up so whether the wastegate was stuck open or something I didn’t know.

Luckily I bought VCDS which is an excellent tool for diagnosing and performing adjustments and if you do a lot of work on VW’s well worth the investment so I hooked that up to see what fault the check engine light was actually reporting and saw the following :

A quick Google of the code P10A4 identifies specific air regulating flap in question but this could also be found by a brief search of the engine bay – there aren’t many flaps in the intake! VW refers to this part as J808.

Image of the TSI160 engine with intake flap highlighted

What this flap actually does is when the supercharger disengages the flap opens providing an unrestricted flow to the intake of the turbo. Obviously if this doesn’t open when the supercharger disengages suddenly the air supply to the engine is closed and you get a massive power loss. You can see what’s going on in the image below which is taken from VW’s manual for this engine – SSP-359. This isn’t a workshop manual but does explain the design and behaviour of this engine in a good level of detail.

There are quite a few guides on how to replace this part such as using the one at workshop-manuals.com . This is an excellent resource but I do recommend using an ad blocker before going there as there are so many ads it’s very annoying otherwise!

My approach to get at the flap was to start at the airbox end and disconnect all the lines going into the intake tract (there are many in all directions so carefully work along it). Eventually once everything is detached you can undo the three long screws which hold the intake pipes on either side tight against the flap and so hold it in place. In my case I ended up detaching the section of pipe after the flap as well so I could lift the whole intake pipe up to get access to the bottom screw nearest the engine as its very awkward to get at otherwise.

Anyway as usual I didn’t want to replace the part if I could avoid it and luckily I found some comments somewhere saying the problem was caused by oil weeping from the intake into the flap unit clogging up the motor so I wondered if it could be cleaned because fundamentally there’s very little that can go wrong inside as they are basically just a motor. Luckily at this point knowing this was likely the problem I figured I couldn’t make it any worse than dead so started trying to work out what was going on.

So looking at the casing of the valve I came to the conclusion there was a simple gearing mechanism inside but based on the space between the clear position of the motor under the curved housing the likelihood was that the gear on the motor itself was small and so I could not explain why there was a significant large area in the housing below it which would likely be a handy cavity with no obvious purpose. The problem being caused by oil makes sense – the motor sits in the bottom of the housing which is underneath the intake pipework so any oil leaking into the housing would pool around the motor. I think the leak is through the spindle bearing for the flap.

So I came up with a plan which may be apparent already because I neglected to take any “before” pictures. I didn’t want to cut the unit open because even though the two halves appeared to be screwed together it looked like the seam had been sealed in some way (presumably part of why oil gets trapped inside) and while nothing appeared to be spring return I really didn’t want to risk it. So I decided to drill a small hole into the extra casing I identified earlier by using the casing as a guide as to where the gear and so end of the motor was. I then carefully drilled a small hole approximate 4mm in the casing and indeed there’s clear space behind this area.

My plan was basically to just flush the inside out with brake cleaner to remove all the oil residue so the hole was just a little large than the straw on the spray can. Sure enough on blasting some into it immediately the predictable brown runoff started pouring out. Another interesting thing happened as well – some residue started to run out of the seam inside the intake passage suggesting this isn’t sealed from the internal workings and in fact the seal on the unit is only on the very outer edge if the housing which may well explain the leaking issue! anyway several passes with brake clean and sloshing it about inside to rinse out as much as possible (I recommend just keep replacing the brake clean until it runs out clear) and it should be ok again hopefully. At this stage you might want to spray a small amount of lithium grease through the hole onto the gears for longevity but if you do just keep it small so you don’t just end up fouling everything with that instead!

Next, make sure the thing is totally clear of brake clean! I held mine under a hot air hand drier for about 10 minute to make it hot enough to drive off all the vapour then left it out in the sun for about half and hour. The last thing you want is a it catching fire!

The final thing I wanted to do is cover up the hole, particularly now knowing the intake wasn’t sealed from the innards. To solve this I tapped the new hole out to M5 and carefully checking the clearance I had behind the cover I put a short button head in place that wouldn’t foul the motor drive gear. Hopefully this also means If I ever have this problem again cleaning it should be easier. You can see the new M5 button head below.

After putting it back into the car I used VCDS to clear the fault code and so reset the engine warning light and took it on a test drive to confirm everything was fine. I think in total this took me about three hours but I was figuring it out as I went so you could probably do it in less.

While this was done during 2020 and so I have been using the car less due to travel limitations and working from home I can confirm that now five months later the car still works well and I have had no further issues following this repair.

Living with a Scirocco 1.4 TSI 160 (118kW) – Part 2, Turbo Replacement

It’s been a little over a year since I posted the introduction blog article on this car and more specifically on the unusual twin charged engine it has. Unsurprisingly over the last year or so I’ve found a few things that need a little work but generally the car has been excellent, needing minimal thought but certainly has some aspects to be aware of for prospective owners to keep the the engine working correctly.

When I bought the car it was a bit lacking power compared to what I was expecting and when accelerated hard in one gear (which due to a seemingly large gap between the supercharger and turbo rev ranges required revving it high) and changed up it would randomly have no power at all. I managed to trace this to a couple problems both related to the turbo wastegate. Firstly the requirement to rev it high was caused by serious wear on the wastegate pivot meaning the wastegate didn’t fully close so the turbo wouldn’t spin up properly. A temporary bodge to get round this is to tighten up the actuator rod to take up the slack but while this sort of helps it actually wears the housing even faster but it can get you by while you wait for a replacement. The second problem of lacking power after a high RPM change was that the wastegate actuator rod was actually bent and touching the turbo housing so it was actually getting temporarily stuck when fully extended so going into the next gear the turbo was basically just dumping the exhaust out the wastegate rather than doing anything useful. So this definitely needed looking at!

First off let me just say I initially looked at the position of the turbo nicely sat at the top front of the engine and thought a couple hours and it’d be done. I was wrong, very wrong! It looks lovely and easily accessible but it just isn’t as easy as it looks for many reasons mostly relating to it not being a turbo mounted to a manifold. the entire exhaust side manifold and turbo are a single unit so you need sufficient clearance to pull the whole unit out.

There it is under the heat shield – looks simple right?

I used various guides to do this swap and generally was in a rush (that didn’t work out so well) so I have very few photos of this but the information is fairly widely available anyway (try searching for guides to the mk6 Golf with the same engine) this is to highlight a few points people may find useful. I suggest referring to workshop manuals for a handy guide with diagrams of each section you need but strongly recommend an ad blocker before you do.

The hard plastic boost pipe which runs from the supercharger to the turbo inlet is retained at the turbo end by a single M6 torx bolt with the threads tapped into the aluminium casting. On the rebuilt unit I bought this thread turned out to be ruined to the point it was impossible to tighten. I suspect this is because undoing the captive fastener during disassembly tries to push a metal sleeve out of the plastic. This is fine in itself but I think it wears the aluminium, similarly tightening it back in will also be hard on it. The reality is the pipe should be pulled back a little at a time as the screw is undone to prevent the load on the threads but this is a bit awkward to achieve as the pipe has very little ‘give’ in it. I strongly recommend checking this before you start – I had to call in a favour because having spent a lot of time swapping the turbo it was rapidly approaching closing time for all the shops to get anything to repair this and without it the car shouldn’t be run. If you’re in any doubt just buy an M6 helicoil kit and put a shiny new insert in place in the aluminium casting because there is only the one screw and if it fails your car will not be happy! Helicoils in softer materials are actually stronger than directly tapping the material the right size because the insert is a stronger material than what it’s going into and because they’re fitted by screwing into a larger thread in the parent material than the desired final thread they have a larger contact surface area in that material.

2. To fully undo all the bolts of the manifold flange you have to undo the alternator mounting bolts and twist it out the way. To do this you have to take off the alternator belt by releasing the tensioner then remove the top mounting bolt for the alternator entirely and slacken the other. This requires removing the engine bay undertrays as well but if you’re doing this job save some time and just pull them all off now. The alternator can then be rotated down and away from the block to get at the bolt. Someone out there might have some creative way of getting at that bolt but I had nothing that would get at it from any angle and couldn’t see any other way if could be done because it’s in a recess with manifold one side, oil filter casting the other and alternator in front of it.

3. Remove the radiator fans. In the picture above you can see how tight this is relative to the turbo and so you need to do this to have enough clearance both to get tools in to undo the manifold nuts and also to remove the the turbo itself from the exhaust studs. Removing these is done from the underside and also involves removal of the pipe between the turbo outlet and intercooler to give sufficient space. You need this removed to change the turbo anyway so it’s no inconvenience.

You’re looking to remove pipe sections 15, 16 and 17 for clearance. Item 11 are two bolts holding the charge pipe to the engine. The radiator sits between the charge cooler and this charge pipe.

The fan module can be removed as a single unit downwards with both fans in place by simply removing the four bolts holding it to the radiator and unplugging it at its electrical connector (item 13 on the bottom edge in the image above).

4. Buy a fitting kit off eBay or somewhere – there are load available but this is the simplest way of making sure you have all the replacement seals and gaskets you might need. Get the most comprehensive one you can find if you can’t easily go to get more parts once this car is apart!

5. The oil drain hose from the turbo is an absolute pig to get at.

The part I’m referring to here is number 12 above and consists of a section of solid pipe at the turbo end with a very short section of hose crimped on. I used a socket on a series of extension bars to get the bolt out of the turbo end but the block end is very awkward to get at because you can’t see it from any angle and the access is tight because the bolt sits virtually under the downpipe. Good luck! When you’re struggling to put it back on after changing the turbo don’t forget the gasket. Also this pipe is apparently common for leaking because the bolt doesn’t get put in sufficiently tightly or the gasket gets damaged during reassembly. I’ve highlighted this below in red.

6. The coolant hard line on top of the turbo needs to be removed which leaves an open rubber hose end. An M8 bolt fits perfectly to block this and stop coolant pouring out over everything so have one to hand before you take it off.

7. Carefully check the boost control hoses – apparently these commonly crack and certainly in my case they were quite degraded around the turbo. You can buy the proper replacement VW part if you wish but it may be cheaper to just order some 5mm vacuum hose and put a run in. In my case I didn’t notice the damage until I started taking it apart and managed to get a random bit from a friend. His wasn’t the common stuff it was thin walled and reinforced so the standard clamps didn’t fit but luckily with some persuasion I managed to fit the thin hose into an offcut of the original one. When combined with a suitable hose clip it’s working fine and has been for ages – that said I do not recommend this option!

Damaged section of hose in red above. The image below shows the hose I replaced marked in red going from the turbo housing back to the boost control solenoid and then the second similar line from the solenoid to the wastegate actuator marked in green.

Unfortunately as I mentioned earlier I didn’t take extensive photos of this replacement but I hope these few points help someone out there!

Good luck!

RX8 Project – Part 18, Resurfacing Cylinder Heads the Cheap Way!

As ever do this at your own risk. For most people you’re better off just getting heads machined by a specialist but if you’re reading this blog you’re probably already aware that’s not always the way I do it!

So this idea came from me wondering how I could easily clean up the cylinder heads on the V6 without additional machining. The heads were generally in good condition so I just wanted a fresh surface for the new head gaskets to seal well on rather than trying to remove any surface damage or warping. If you have this sort of damage this method is not for you.

When I came up against this problem I decided to do some research and found quite a few people online saying you could just do it with suitable abrasive paper and a sanding block. Now I get the idea but the engineer in me sees a good possibility of some part getting ground back more than another actually increasing the issues with the head that we’re trying to remove in the first place. Around this time I spoke with a few different people who have experience with engines and they all said much the same thing – machine skimming is safest and easiest but with enough care it should be possible to do a perfectly good job by hand, the problem is getting the whole thing completely flat which is very difficult by hand. Most people who had done this seemed to have done it on engines with small cylinder heads such as single cylinder machine engines which being small are easier to get flat by hand.

The problem was absolutely one of getting something suitably flat that would cover the whole head to get the whole thing even so I started looking into what might work. I was already aware of engineers surface tables which are used for checking flatness but these are large, heavy and very expensive as they’re often made of stone or tool steel. I then looked at getting some surface ground steel plate (where a thick steel place is ground to a precision flatness) but again this seemed to be expensive and awkward. After a bit of thought I had an idea…

Ok, so at first glance this seems like a daft idea but stick with me! The cheapest and most rigid precisely flat surface I could find was a piece of toughened float glass. Specifically toughened because it is created in such as way as to pre-stress the surface which makes it both stronger and stiffer but also much more brittle – this is the glass that breaks down into granules when broken rather than shards. Initially my plan was to just order a decent sized bit but that seemed rather wasteful so I thought about it and realised second hand furniture included quite sizeable bits of the glass. I began searching eBay and Facebook marketplace to see if I could find something suitable as cheaply as possible and after a week or so found this coffee table. It was nearby and listed as local collection only with some damage to the wood veneer and scratches on top surface of the glass (so the price was unlikely to go high) and 99p no reserve starting. Couple days later I was the proud owner of a £4 coffee table!

Now you may be wondering why we aren’t bothered about the surface scratches on the glass which is likely to be a problem with any similar furniture. The reason is twofold, firstly due to this being toughened glass any scratches are likely to only be very minor and secondly the glass has a whole other side which is unlikely to have any scratches anyway so we’re going to use the underside.

I took the table apart carefully removing the top and to give additional support I placed it flat on a 19mm (3/4″) thick bit of chip board carefully screwing an section of baton at each end to stop the glass sliding about while we’re working. This assembly when then placed on my carpet which is just very hard office carpet tiles on concrete so shouldn’t allow any appreciable movement so hopefully with that stack of support the glass should be perfectly flat even with a cylinder head on it! The abrasive I will be using is wet and dry paper in a range of coarseness, get a pack of each grade you plan to use, it will take a lot of it! I made sure the wet and dry would stay in place by spraying the back of it with spray mount adhesive and putting it in place. Spray mount should also peel off relatively easily when we need to change the paper. I used 3 sheets to create an area larger than the head face in both length and width.

So now we have our setup we need to prepare the cylinder head for this. When it came off the engine it was quite grimy as you might expect so this needed addressing.

So here you can see how it was when it was (almost) fresh off the engine but with the residual head gasket material scraped off. You can see the amount of grime isn’t too bad, I have already wiped some off the top half but the bottom is a bit more representative. You can also clearly see the outline marks from the head gasket that we’re looking to remove later. This step basically involved soaking the mating face in a de-greaser then wiping it all off carefully.

Head after degreasing but before refinishing

It’s not perfect but it’s a huge improvement on where we started. The combustion chambers are considerably better. There’s some residual on the face but its more staining than anything else and will be removed by the refacing. So now we’re ready to go.

First cover the wet and dry with your chosen lubricant – water should work but I found WD40 seemed to work better as it helped the head ‘glide’ more. A light oil like 3in1 would probably be even better as it’s a little thicker again and WD40 tends to dissolve the spray adhesive as you work making the wet&dry come loose. Take the head and place it on the wet and dry (I started at 120 grit) holding both sides lightly start to slide it across the surface. There are different approaches to this where you can angle the head first one way then the other to give a crosshatch pattern. In my case I generally moved it in a long oval and this seemed to give a nice even finish but as ever your mileage may vary!

Cylinder head sat on DIY refinishing setup

You will find that as you work the oil and metal shavings will spread so I suggest doing it somewhere you don’t mind the mess!

This will take some time and effort. If the wet and dry wears down replace it. when you’re happy with the initial surface being clean of all the minor marks and debris you can go up to increasingly fine levels of grit for a better finish.

On the subject of finishes when I was doing this work I found the following information which relates the abrasive rating with the achieved resulting surface roughness – if anyone knows where this is from please let me know as I can’t seem to find out.

US Grit	UK Grit	Ra µm	Ra µinch
	P120	3	125
	P180	2	85
80		1.65	70
	P240	1.5	50
	P320	0.75	30
180		0.62	25
240		0.45	18
	P500	0.4	15
320		0.25	10

Comparison of grits vs achieved surface finish

So in the context of this I’m working in UK grit. Unfortunately the only information I could find on the required surface finishes for head gaskets came from the US so is in Ra µinch (Ra being the roughness average of the surface) but luckily this table equates everything. Generally normal gaskets seem to need a surface finish of about 50-60 Ra µinch, modern multi layer steel head gaskets require 30 Ra µinch or smoother so we need to finish at a minimum of P320. I actually went up to P400 to be safe.

Comparison between not touched and work in progress cylinder head

This is the comparison of the untouched head and the one with the first couple of grits done and so not quite finished but you can see the massive improvement made here.

I know judging by eye isn’t accurate but it’s clearly doing something good!

Keep going until you do all the grits you need and when you’re done then you need to check the flatness. I did this with an engineers straight edge (as opposed to a builders straight edge which is a big ruler) which cost £25 off ebay. This is a bit of steel that has been precision ground to be completely straight in one plane so is often only a couple mm thick but 70mm wide or more. You check the flatness by putting the straight edge perpendicular to the head (so it sticks up) and trying to slide a feeler gauge under the mid point (or as close as possible) of the area you’re checking. You need to check the width, length and both diagonals but also check across all the bores. The head should have no more than 0.075 mm off flat over the longest span on an iron head, or 0.05 mm off flat on an aluminium head on a V6. In my case the smallest feeler I have is 0.04mm so that proved it was good enough but to check it further I got some thin foil, checked the thickness with a digital micrometer which came out as 0.01mm and placed the foil on one of the central bridges of the head and put the straight edge on and it rocked on the foil. I then redid the test with the foil at the ends and the same again in other directions. Each time the straight edge was clearly resting on the foil first so the head must be flat to <0.01mm across the whole head. Unfortunately I neglected to take any photos of this stage but there’s plenty of information online.

That’s about as good as it gets so our £4 coffee table looks like a success. Plus I still own a coffee table – albeit with a few new scratches!

RX8 Project – Part 17, Changing to a concentric clutch slave.

To preface this I’ve not actually run the car with this setup yet so please make your own decision if you give it a go. This was done on the gearbox from a 2006 year RX8 5 speed box so may not be applicable to others. It looks like it should work but that’s only my opinion – your mileage may vary!

So this is a bit of an odd problem which depending on the engine you’re swapping in may not be and issue but in my case I decided a V6 was a good idea and unfortunately the standard clutch slave on the RX8 gearbox is on the top offset to one side which lines up perfectly with one of the cylinder heads on my V6. Add to this if you made the better decision mentioned earlier and made the adapter thicker you may be able to avoid this as well. But since I’m largely making this up as I go along here we are!

Now I did look into whether anyone offered a concentric slave conversion for this car but it seems that was never a thing anyone did so I set to work building my own. Luckily there was one thing I knew which would help this process quite a bit – the input shaft on the gearbox is the same diameter/spline as most Ford patterns and so a Ford part should be exactly the right clearance. Add to that I’m actually using a Ford clutch if I get the depth right everything should just match up ok.

So that’s the good news, the bad news is the RX8 gearbox was never intended to be used in this way so mounting a cylinder could be an issue. Now on the RX8 there’s a flanged sleeve mounted which the original release bearing slides on the outside of. This is held on by four bolts into the back of the bellhousing and so this appeared to be essentially the only option. The tube itself can’t stay because the new concentric slave is the same ID and so clashes with it but I thought why don’t I just unbolt the tube at the flange and bolt a suitable adapter there and we’re good to go? Well it’s never that easy is it. Under that flange is a location lip which not only keeps it concentric to the gearbox input shaft but it turns out it also the height of the shoulder accurately holds the input bearing in place behind it so if I just remove that whole part the bearing will move out of position and that will very likely result in it not having enough support and rapidly removing itself from the gearbox in small pieces.

3D model of the RX8 gearbox input bearing retainer — Unfortunately I can’t find a photo of it but the part looked like this!

Ok so I can’t just remove the flanged tube and stick an adapter plate on but how about cutting the tube down to the flange to leave a flat face above the bearing retainer and just using some longer bolts to keep it all in place. After some very careful trimming I was left with this:

Next was picking a suitable concentric slave from the Ford range. After a bit of poking about and trying to find something I could make fit I found the Teckmarx TMCS00047 which is a 3rd party part number for a 2001-2007 Mk3 Mondeo/Cougar among others which as you might have read earlier was also available with this same V6 engine I am using and this model has a few advantages firstly that both in and out hydraulics are in one direction so if I make that line up with the original position of the clutch fork I should have easy access and also that they’re threaded the standard M10x1 brake fitting thread so I can direct connect hoses or hardline as I need to make it work. another major advantage is they’re used on loads of versions of the car so they’re widely available and very cheap at under £25 delivered. It also seems that the RX8 also has almost same clutch master cylinder bore as the Mondeo (18mm vs 19mm) which should mean pedal travel is still sensible.

Now with the clutch slave accurately 3D modelled I could measure the 4 bolt flange from the gearbox bearing retainer and by overlaying the two bolt patterns aligned on the centre of the input shaft I could design an adapter which I could index the relative rotational angle of the bolt patterns in the software until the fluid connections where in the right place for the hole in the bellhousing. The resulting first version was this :

Initially I transferred this to a bit of scrap plastic to make sure I hadn’t made any stupid mistakes before spending much more time cutting a proper steel adapter plate.

Plastic prototype RX8 clutch slave adapter

So with all that checked out and nothing apparently an issue I moved onto the steel one. I did make a mistake here if you can spot it…

To make the adapter I did the same as I had done with the plastic where I printed out the design at 100% scale, stuck it to the steel and then used a centre punch to mark the centre of all the drill positions. I admit this isn’t the most accurate method but it seems to work quite well!

This is the initial adapter, the four larger holes are M8 clearance holes. on the original RX8 flanged retainer they’re 9.4mm but I think I did them 8.5mm as that’s the drill I had available and tightening up the tolerance was probably a good thing. This actually turned out to be less of a problem in the end but that’s another story. The centre hole is larger than the original design to allow for the location feature I’d overlooked on the new slave (which is 42mm OD) to sit within it.

Clutch slave adapter trial fitted to the gearbox

So it fits, I called this good progress but it should come as absolute no surprise that it wasn’t quite that simple…

Clutch slave unit fitted to adapter plate

As soon as I tried to add the clutch slave all the issues become apparent as it just clashed with everything. This told me that I’d need to change the adapter to countersunk bolts so the slave didn’t foul them. I could have changed the rotation but I wanted to avoid having lengths of pipe in the bell housing if I could. Plus I’d already made this steel adapter and didn’t want to do it again!

The other thing I noticed is that the cast webs off the original pivot point actually clashed with the adapter plate preventing it from quite sitting flat so I decided to remove some of the plate to correct this minor issue.

Now the adapter sits flat and at the same time I countersunk all the adapter bolt holes and replaced the bolts.

It all fits more or less where I wanted it but when I tried to bolt up the gearbox I saw another problem. With the bearing retainer plate, a sensible thickness for an adapter plate and the height of the concentric slave itself the slave was already almost fully pressed down so that which it may have worked initially as the clutch wore the slave would prevent the clutch from fully re-engaging. Clearly not ideal so we need to get more radical. First off the back of the clutch slave had a lip similar to the one on the RX8 flanged plate which initially I was just going to leave on and sit on top of the bearing retainer plate as it was slightly thicker than the adapter plate but that just wasn’t an option any more. Below you can the way the slave is totally compressed. Also note how close the hydraulic connection point is to the original pivot point casting.

Stack height issues in the new clutch assembly

This lip was adding a couple mm of stack height we needed to remove so I proceeded to carefully file the lip off down on the slave such that it would sit full within the adapter plate and ideally totally flush to the back of the plate.

On trying to refit this in its new position I realised I’d created another problem that I glossed over earlier – that I’d need to remove some of the original gearbox casting to make the new slave sit flat in the orientation I needed as the original clutch fork pivot point clashed with the location where I wanted the hydraulic connections on the new slave. The best method I found was a drill bit larger than the feature and just drill the top of it away until it clears the new slave.

Around this time I realised really I needed to remove the original flanged bearing retainer plate as it alone added about 4mm to the stack height so I engaged in the type of butchery that makes engineers wince. I took the flanged retainer and trimmed the flange off it. Yes I specifically mean that – if you cut through the bearing retainer ring it will reduce the height such that the bearing is no longer held tightly so you need to carefully trim off just the flange plate leaving a ring the right height fill the gap between the bearing and where the retaining plate face would be. because the new slave retaining face was now flush with the adapter plate this ring will now be held in place by that. Removing this plate now meant I had to drill yet more out of the pivot casting to prevent it clashing but that’s easy.

Final fitment of the concentric slave conversion from the original fork position

Now everything is in place and the hydraulics are accessible through the original clutch fork hole.

And all back in the car…

For anyone who may want it here’s the PDF drawing for the adapter :

RX8-concentric-clutch-adapter Download

Start of 2020 Update

Apologies to anyone who’s been waiting for an update on any of the projects I’ve put on here – I’ve had a lot going on over the last year and writing up all of this information takes me a lot of time so has taken a bit of a back seat. None of that information has been lost and I hope to start catching up on all of this over the next few months.

Where we are right now :

V6 Mazda RX8

The V6 engine has been fully rebuilt and has been sat in my living room next to an engine crane for about 8 months now, Partly this is due to me not currently having a garage to work in and it being winter and partly due to being very busy last summer. But yes, the project is still ongoing and hopefully will make good progress this year.

Six million dollar welder

Is still on my workbench awaiting the last couple of bits. I’ve had to swap out 24V PSU’s a couple times as they couldn’t deal with the current of the new feed motor. It now works but needs the relays mounted to the panel so I need to remember to find 4″ of DIN rail.

DL180 Server

Is still working beautifully after the Arduino fan controller mod. It’s been hosting this blog ever since so something like 12 months now without a problem. It also provides the storage for my CCTV system.

Hikvision CCTV

I’ve got a couple of updates to write about expanding the system beyond the original one camera setup I wrote up last year. Using multiple cameras with network storage seems to be poorly documented and have a few interesting quirks but after some work I got it working fine. The biggest problem I’ve had since is when the local police asked for my footage following a nearby break-in I had to supply them on a 1 Tb hard drive! High resolution digital video takes up a lot of space!

Other Projects

I’ve had various other projects going on as well. I’ve started looking into using NodeMCU WiFi microcontrollers as sensor nodes with their own web servers around my house with NodeRed requesting the page and parsing the HTML to return the information I want. I can read the temperature sensor connected to the nodes and control the LED on the MCU from NodeRed. Currently the data is not stored because I ran out of time trying to get MySQL setup. I’ll write this all up at some point

Raspberry Pi’s – I seem to have collected a selection of Raspberry Pi’s somewhere along the way. I have a Zero, a ZeroW, 1B (which in a different life I turned into a PoE CCTV camera), 2B and 3B plus I think somewhere there’s another 2B. I really should do something cool with them!

Wooden storage box – I started restoring a large wooden box some time ago. The box used to be in my granddad’s workshop as a toolbox for many years and before that I gather it belonged to his uncle so it’s been around for a long time and has suffered a bit with use and age with some areas with woodworm damage and the rope handles badly degraded. It has also been painted brown at some stage so I’ll need to get that cleaned up as well. I intend to restore it to a ‘usable’ condition so rather than trying to make it as new just tidy it up, repair the damage and make it solid enough not to degrade further but still look like the well used item it is.

Subwoofer project – Has been in constant use for ages despite never being technically finished. I really need to actually finish it and write this up!

There will be more but I think that’s enough update for now – rest assured I’ve not stopped! Especially since this morning another turbo arrived in the post, the fourth I now have here….

Upgrading a SIP Migmate 130 Turbo welder – Part 2, The 6m Dollar Welder

So after it had been left abandoned in a cupboard for a couple years I was recently contacted by the guy who actually owns the old SIP Migmate welder saying he had a couple projects to do that would be good for a MIG but aware we’d previously done it serious damage to the torch he’d found a wire feed unit with a euro torch connector on ebay and could we make it fit. Well of course we could, what could possibly go wrong! Before I knew it he’d ordered it to ship to me so I guess we were modding the welder again. We can rebuild it better than it was before!

Upgraded Wire Feed

So this is what turned up – clearly a different beast entirely to the original plastic rubbish. Don’t be mistaken, it’s a top quality Chinese unit but it is significantly better built than the original – one being mostly metal it doesn’t deflect under load. Add to that the motor is rated at 40W which is probably four times more than the original one it should be able to drive wire through longer torch leads with no problem.

You can clearly see the significant difference in the units in this picture. But that isn’t going to stop us!

First off we need to remove the existing feed unit. These are held on with four pop rivets which are quickest removed with a power drill. To extract the drive unit the torch must also be unbolted from it with the one retaining nut.

So at this point you should be left with this :

At this stage you’re probably wondering how this will work, and if (however unlikely) you’re attached to this welder you probably want to stop reading, this will not be pretty!

If you’re you’re not attached to the welder I suggest finding an angle grinder and getting busy!

The key thing to note here is because the new drive is for a euro torch it is energised by the main supply so no conductive part of the feed drive can be in contact with the casing. Add to this the new unit has an adjustment on the top which needs clearance under the case the feed motor cut out needs to continue much lower down.

Due to the feed mechanism being physically wider the connector for the euro torch connector will sit further out than the original torch outlet. In an ideal world I’d have relocated the the wire feed to the bottom of the welder but the outlet inductor is behind the panel and I didn’t want to go trying to move that enough for that idea to be viable.

The first cut doesn’t look too serious, then hack the front out :

Hmm, yes I’ll work out how to cover that up later!

Next up we make a plate to hold the euro connector. This is to prevent any movement on the euro connector causing it to hit the case which could end very badly. I found a random bit of polycarbonate I had lying about drilled a clearance hole in it then worked out where it needed to sit. The horizontal position here is less critical as we can adjust it on the mounting later. The plate needs mounting holes to fix it to the front plate so drill and bolt this. A trial fit then also identified that when the new feeder was fully forward in position more clearance was required in the internal plate so this needed a little more butchery.

New mounting for replacement wire feeder

The blue wire dangled through the divider in the picture is actually the trigger wire for the welder something we’ll need to sort out later to actually make it work.

So here’s the trial fit, nothing touching the case where it shouldn’t and all seeming to fit well. around this time I wanted to get a matching torch for the upgraded welder so I went to my favourite welding shop (Noz-Alls in Cheltenham) to pick one up and while there I explained what I was up to with the welder and he helped me out with some more bits he had. Specifically I wanted to upgrade the welder from using 0.7kg wire spools to 5kg spools so I needed a new mount for the reel and not only did he have something he also mentioned that I’d suitable gas valve (the welder originally had a mechanical one in the torch but I hadn’t even thought about the fact euro torches don’t have this. Again he had just the thing available for a few pounds so I got that as well.

Now that looks more like a proper setup, this new mount just bolts through the divider plate. Next up we need to mount the drive motor itself, it is critical to remember the black plate under the drive must remain to insulate it from the mounting bracket. I originally intended to mount it with a section of angle but in the end I came up with another alternative. I had a short offcut of 40x40mm aluminium profile with a couple angle fixings which by luck was perfectly sized so I decided to use that up.

Something I should probably note here is using either durloc or nyloc nuts on everything I can and make sure everything is good and tight. The owner of this welder can be hard on equipment and I want to be sure that when I hand it back it won’t just fall apart!

That’s the wire feed and 5 kg reel setup all installed. So now back to the problem I mentioned earlier with the gas valve. The black hose coming off the back of the euro connector is the gas line, I need to connect this to a valve. I decided to mount the valve on the electrical side of the welder because my plan was to drill out the original hole the gas hose entered through to take a more standard 3/8″ BSP threaded fitting.

Gas Valve

The valve I bought is a direct fit to the 5mm ID hose off the euro connector. The valve inlet is an 8mm barb so I bought an 8mm to 3/8″ BSP female hose barb and screwed it into the back of an 3/8″ BSP bulkhead fitting. The bit of hose is a section of 8mm fuel hose I had lying about. The valve actually has a nut on one side to allow it to be mounted to a panel, in this case I mounted it to a section of aluminium angle. These valve are available in a range of voltages; usually 6/12/24VDC in welders but others are available. Since the feed motor is 24 VDC and we need this to open when the feed is on it makes sense to use the same then we only need one trigger switched supply for both.

Earth lead

So with the addition of a detachable torch I thought a detachable earth lead might be a good idea. I bought a 10-25 dinse connector off ebay, this comes as a plug and socket pair where the socket fits through a hole in the panel and the plug is bolted onto the end of the cable. To mount the socket I undid the clamp inside the welder where the cable was fixed to the supply transformer. The cable is held in by a plastic clamp so just undo that and pull the cable clear and remove the clamp from the panel. As it turns out the panel hole was fitted with a dinse connector in a different model and so they actually fit the panel perfectly with the anti-rotation key even fitting. Again for the power connection to the socket I used a 10mm re-usable cable lug but had to fold the solid core from the transformer back on itself so the clamp would tighten onto it solidly.

Wire Feed Controller

I decided in the end rather than bothering to improve the existing speed controller which is well documented to have issues I’d simply replace it with a modern PWM DC motor controller. PWM controllers generally allow a very wide range of adjustment and because they apply full voltage the motor retains excellent torque even at low speeds. So I bought another quality Chinese board off ebay and after a couple weeks I had one of these:

These go for about £2.50 and from my initial tests with a 19 VDC laptop supply and the new 40W motor it worked perfectly and it gave very smooth control up through the full range. The only thing that might need adjustment later is that full speed seems excessively fast for a welder but this is something to assess when the motor is loaded. With the smoothness of the range this wouldn’t be a problem but if we don’t need it later it would be better to add a resistor to make the controller only go up say 75% full speed when the dial is at maximum. But we’ll worry about that later.

The next problem is the nut on the potentiometer which would normally hold it in place fits right through the original hole in the panel. So I found a large penny washer which it would tighten up on and drilled two holes in it. This washer was then pop riveted to the front panel. With the knob back on you cant even see the rivets.

New motor controller — Rear view of the new controller

And the front view – you can see the other additions as well

Now, you may notice I’ve taken out the original PCB. This is partly because we needed the spot for the new speed controller but also because that makes about half the PCB redundant. The only other things on the PCB are a small 12V PSU (to drive the main supply relay), a couple line filter capacitors and a 16A relay which switches the main supply. My plan is to replace the relay with a 24V coil one and run all the control off the separate 24 VDC supply.

More to follow in the next update!

Upgrading a SIP Migmate 130 Turbo welder

Sip Welder Manual Download

The story of this upgrade starts with a friend of mine acquiring it about 15 years ago (at which point it was already quite old) and after some use real life got in the way and it was abandoned in a barn for about a decade. At this point I needed a welder for a project and asked to borrow it. Now when I got my hands on it and started trying to use it it became immediately obvious these welders were amazingly basic and poorly constructed and so immediately I started modifying it to make it work a little better.

Factory Wire Feed

First off the standard wire feed is terrible, it’s made of plastic and if you put enough pressure on to push the wire the mounting for the drive (being plastic) actually bends away and just won’t consistently grip. This situation can be improved by changing the plastic torch liner out for a steel one to reduce friction but it’s still dodgy. Bracing the wire feed on the outside helps as well.

Here you can see the feed modification. It is simply a bit of scrap metal with a slight bend in it and two holes. The two screws are already in the feed system and hold the parts from the factory so it just picks up on them. This simple mod helps the two feed rollers from deflecting away from each other.

The next issue with the wire feed is the motor is driven off the main transformer output with half wave rectified DC which causes a one main problem, the supply to it isn’t consistent. When the arc is struck the voltage at the motor will drop due to the load change on the transformer which tends to make the motor constantly pulse in operation rather than give a consistent feed so it’ll join metal but not in a particularly convincing way.

To get round this I added a small regulated 24VDC supply for the motor with the help of information I found on the internet such as the wiring diagram for the welder. The was this works is the control board gets its 24V supply from the black wire on the 4 pin connector. If we disconnect this and instead feed it our own 24VDC the supply shouldn’t fluctuate any more. I used the existing supply (the black wire we just intercepted) via a relay (24VAC coil) to turn on the wire feed when the output energises. You should end up with something like this

I’ve not checked the rating on the factory feed motor but I would guess 10W at most. I used a 24VDC 15W PSU module (specifically a Tracopower 15124C that I found on ebay) and it worked well. I managed to fit it behind the main transformer bolted to the outer casing.

Further to this the motor speed circuit is actually very poorly designed and after a little use can get twitchy and change during use. I didn’t get as far as modifying this but further information can be found here :

Wire speed mod

Or if that should ever go offline also in this PDF :

Migmate Wire Feed Download

Earth Lead

Another key usability thing is that these welders have very short leads and the clamp was poor from new and appeared to be a similar thickness to tinfoil and added to that was badly damaged and even rusty and since poor contact causes many issues with consistent welding so I decided to upgrade the cable and clamp to help the situation. For a welder this size you need to be looking at a minimum of 10mm2 cable but this will not allow you to operate at full power consistently (not that this welder is actually capable of that anyway!) 16mm2 would give you plenty of spare capacity.

The clamp itself was just bought off ebay again, they’re about £4 each so difficult to go far wrong. You could go for a different style to the normal clamp if you prefer such as a magnetic one. To connect the cable to the stud on the clamp I used a reusable cable lug which uses two small bolts to tighten to the cable, you could buy crimp lugs but crimping them without the correct tools can be hit and miss. I’ve heard a cold chisel will work but your mileage may vary. I actually used a second reusable cable lug to clamp the new cable onto the transformer outlet inside the welder – not the neatest solution but it worked.

Gas Supply

The standard shielding gas supply on these welders is via a small plastic tube which is intended to be connected to a mini-bottle which sits in two brackets on the back. The brackets aren’t actually fixed to the welder so can be easily knocked off. The standard regulator is rubbish and the one I got with the welder was totally seized shut. I bought a like for like replacement initially and this highlighted the limitation here. The bottle is so small and the regulators so poor that the gas flow actually changes during use and rapidly empties entirely. They have no gauge and so the first you know of having no gas is when your welds go horrible. I looked into it and found a good solution – you can buy regulators that adapt a normal gas bottle to this type of hard line.

I looked into getting gas and found that the time of massive rents on bottles is over. In the UK there are a couple networks of suppliers who will give you weld gas with only a bottle deposit (currently £65 for mine) and no ongoing rental charge. Once the bottle is empty you take the bottle back and get a full one and just pay the gas fill cost (about £30 for the bottle I have) I found a supplier of Hobbyweld gas (Noz-Alls Cheltenham – www.weldingdirect.co.uk) and got their 10L bottle, these are pressurised to 137 Bar giving a total of 1370L of gas. This lasts drastically longer. The shop I went to also sold a standard regulator but with a crimped hose and a push fit to suit this welder off the shelf making this very easy for about £20.

Roll Drag

One other problem I had was the tension spring which is supposed to hold the roll under a little tension to prevent overrunning was actually sharp and biting into the reel. I added a large flat washer under the spring to stop this then added a small washer as a shim to prevent it being over-tightened. This provides friction over a large area to avoid this problem and it seems to work well.

So once I’d done all of this it worked significantly better and we used it for a few projects to good effect right up until we tried to repair and refit the load bed of a pickup truck which involved welding plates onto chassis rails and various other extensive welding work. After burning through multiple contact tips and a couple shrouds we got to the point where the torch died entirely with the wire welding into the inner workings of it and came to the conclusion it was done for. The torch on these being hard wired into the unit finding a replacement wasn’t as simple as a standard euro torch and at this point I wasn’t sure it was worth replacing until we actually needed it again. Some time later I bought a new compact R-Tech MIG which by comparison is a revelation and so the old Migmate got thrown into a cupboard for storage with the expectation it would eventually probably be scrapped.

Though that’s not exactly how the story ends…

Living with a Scirocco 1.4 TSI 160 (118kW)

So recently I finally decided it was time to retire my previous long suffering car – a 2003 1.4L Mk1 Seat Leon I’ve had for 10 years! When I bought the car in 2009 it had 62,000 miles on the clock, now it has 198,000 miles on it and needs to be run on 10W40 rather than the specified 5W30 just to stop the engine rattling. The Seat did well but it had a hard life including 3 years commuting 400 miles a week and had got to the point where I was fully expecting it to fail sooner or later and wanted something that wasn’t as underpowered.

So I started looking about for another car and the new style Scirocco caught my eye. After looking for a while I found a decent condition version with reasonable mileage, service history and not reaching a high bid. Detail on this car was a little lacking as it was just described as a 1.4 TSI but the car had no engine/spec badges (a factory option from VW) so I wasn’t sure which version it actually was but on the basis it wasn’t advertised as the higher power option it would be the lower power turbo only 122 bhp model. So I went for it and got it for a decent price. When I arrived to collect it having never actually seen it before I checked it and found the identifying sticker in the boot which showed the power as 118kW, this is 160bhp so I’d got the more powerful one.

Image of a 2010 Scirocco — Something like this one.

This is both a blessing and a curse because while obviously it goes better the 160bhp version also have a reputation for unexpectedly experiencing catastrophic engine failure.

That said always take forum posts on the internet with a pinch of salt – people rarely take to the internet as much when their car works perfectly.

By this point its too late to back out so I’m now the owner of a Scirocco with a 1.4L engine! So now I start looking into things I need to watch out for. The engine is the first interesting thing here as it’s both supercharged and turbocharged to give a much better low down grunt than expected from such a small engine with supercharger boost while still having a wider power curve by the turbo taking over at about 3000 rpm and working higher up. The engine peaks out at about 1.5 Bar of boost (22 PSI) from the factory. This system obviously adds complexity and potential points of failure with various valves and clutches to make it all work so a number of things to keep an eye on.

VW Technical guide to this engine available here

Clearly we’re playing with a fairly highly strung engine so my first thought is what the maintenance schedule on these was like. People tend to ignore their cars so long as they keep working and from my previous 1.4 VW engine in my Seat I’m aware they have some issues with oil consumption. On my first look at some of the reports of damage online most seemed to mention failures that could easily be a result of oil starvation. Again, something to keep an eye on.

Moving beyond the engine that car itself is fairly advanced as well. These cars come as standard with adaptive suspension designed to react to road conditions. It has four sports seats which are very comfortable and the boot is quite reasonable for this type of car. Internally the Scirocco is very similar (depending on model year) to either a mark 5 or mark 6 Golf but is a bit less practical due to the style of the vehicle and lower roof line. That said I’ve had four full grown adults in mine and while it’s not hugely roomy it’s comfortable enough.

Now for the the but – I think mine was cheap partly because it has none of the extras. It doesn’t have cruise control, it doesn’t have HID headlights, it doesn’t have the more common 18″ ‘turbine’ wheels (I have the 17″ shown above), no DAB radio and no bluetooth. Other than the twincharged engine its a basic model and for most people that would be all there is to it but that’s not how I work. I will improve it as I go along and hopefully record how I do it all on here!

RX8 Project – Part 16, Fitting Piston Cooling Oil Jets

These are something I hadn’t really come across until I started working on this project. While I was researching the work Noble had done developing their twin turbo engines I found the installation of piston cooling oil jets noted as one of the modifications undertaken. On the basis they found it was fine to use the stock pistons but did this mod I started doing research into what exactly they were and why they were used.

The usage of these jets seems to be almost exclusively related to turbocharged engines, both diesel and petrol due to the amount of energy released in these engines. This increased release of energy caused by burning more fuel in pressurised air generates much higher temperatures inside the engine and while the block and head are actively cooled most normal engines rely on incidental oil spray to keep the piston cool. Once you start getting the piston considerably hotter you have a couple options. Either use a piston material which will cope with much higher temperatures without degrading (either due to the temperature affecting the material properties or due to thermal expansion) or somehow cool the piston. Various materials have been used for high performance pistons to help negate the material strength and thermal expansion problems with varying degrees of success but these are generally very expensive made to order parts and well beyond the range of most. This is where the jets come in.

The jet is usually some sort of nozzle drilled into an oil gallery in the block which directs a stream of oil at the underside of each piston. This both cools and lubricates the piston and rod small end/pin.
The original Noble modification is known to have some issues but this was more of a problem with the implementation. Take a look at this : http://noblecars.org/engine.html

The basic problem of the original Noble method is that with such large drillings (probably about 4mm diameter) the cooling will be very effective because the flow rate will be high but the overall engine oil pressure will likely be very low, particularly around the main bearings because that is where they are drilled into the oil supply. Clearly the one place you don’t want low oil pressure!

So me being me I decided to improve on the situation! Firstly I found that most cars that have these fitted (unsurprisingly) use considerably smaller jets, the best example I found was a NASCAR engine using a jet of 0.75mm (I have since tried to find this page again with no luck). Not wanting to risk trying to drill a hole of such a small diameter freehand at the bottom of the cylinder bore from the top I took a slightly different approach and started looking for suitable nozzle inserts that I could use that were available easily and cheap. After a lengthy search trying to find something intended for the purpose (from either a suitable production vehicle or something) I gave up and started just trying to work out what I actually needed and realised that with the rise of home 3D printing small nozzles were actually easy to get – specifically the extruder nozzles used on these printers. These nozzles are usually brass, have an M6 thread and are available in a range of hole sizes, for me the 0.8mm version looked like a good match.

I bought a pack of four nozzles off eBay for a few pounds and decided I should see what sort of spray I actually got from them – I wanted them to produce a fine jet at the normal engine oil pressure rather than a mist as this would assure the oil reached the piston rather than most of it just hitting the inside of the cylinder bore which would achieve nothing. Because I’d decided on the M6 thread it made a test jig quite simple, just a normal M6 nut welded on the end of a bit of 12mm tube. When welding anything threaded it’s a good idea (particularly on smaller threads) to put a suitable mating part in to prevent distortion if you can. In this case I used a standard M6 bolt. After welding the nut the bolt can simply be unscrewed again but if you don’t do this the heat will often distort the thread enough that it is unusable after welding. The 12mm tube just happened to be about right for the nut but also a good size to allow a normal garden hose to fit over it. Water pressure in the UK is nominally about 3 Bar which is at least in about the right area to represent an oil pressure. Also there is the question of viscosity but my logic told me that oil being more viscous than water should not form a mist as easily, so if it worked with water oil should be fine. The test showed a solid jet out to about a meter from the nozzle and beyond that a tight stream of droplets another meter or so. This should certainly be good enough for what I need!

After this test I decided to go for it, so I ordered another set of four nozzles and started trying to work out how to actually machine the block to make them fit. Due to the position the jets need to be installed the oil feeds need to be drilled from the crank bearing housing 60° either side of the centre line to match the cylinder bore angle and also at a slight angle forward or backward (depending on which cylinder it is) so they actually come out into the shoulder at the bottom of the bores rather than just continuing between the cylinders.
First off I marked up the 60° line for each bore so I had something to line the drill up with for the angle and the starting point for the drilling. Next I found a drill bit that nicely fitted into the groove in the bearing housing so as to avoid reducing the supporting area for the bearing which as it turns out is a 3.2mm. This is the area that apparently will crack on the Noble engines – they use a significantly larger drill hole here which breaks into the bearing support lands and I suspect this is part of the issue but that’s purely speculation. There is also no issue with restricting the flow to the jets here because the jets are now significantly smaller than drilling. The next important thing is this involves drilling quite a long, narrow diameter hole through aluminium and that can be quite problematic!

First off let me say this is next bit is a bad idea all round, you either have to be very confident in your abilities with a hand drill or not care if you ruin an engine block. Ideally you want to be both! If not you will want to talk to a machine shop to do this!

Before you start remember to remove the bearing shell itself and put it somewhere safe! Aluminium is a soft material and will stick to drill bits and tend to generate heat due to friction, if it gets hot enough it can actually seize onto the drill bit causing it to break. Firstly a normal length 3.2mm drill won’t be long enough for this job, it will work to an extent but the flutes will eventually be covered by the sides of the drilled hole when you get deeper and there’s nowhere for the chips of aluminium to go. My advice is to buy a long series drill bit and use it. Start the hole with a normal bit because long bits are more flexible and can be harder to get and accurate start with but once you have a dimple that will hold the bit in place swap to the long series. Use plenty of lubricant (go on, guess how I found that out!). You can use WD40 but it can get quite expensive if you have a few holes to do as it tends to vaporise off during cutting. Thicker oils tend to protect the cutting edge more but make cutting slower but in this case aluminium is soft and so drills quickly anyway plus we’re only making a small hole so it will make little difference. Personally I used 3in1 on mine with works well and helps flush the chips out but you will need to reapply the oil to the hole regularly during the process to make sure the drill is well lubricated. You could also use engine oil or even gearbox oil but these would probably slow the process a little more. Go slowly and let the tool do the work, if you push too hard there is a serious risk of flexing the drill bit which at best will give you a hole that wanders and at worst a serious risk of snapping the drill bit.
Once the 3.2mm hole comes through into the shoulder at the bottom of the bore we need to make the M6 nozzle fit, this means tapping a suitable thread into the bore end of the drilling. First clean out all the swarf (drilling debris) from the new hole. At this stage this is just to make sure we get a nice clean thread cut. Now we have the interesting bit, to tap M6 we need a 5mm pilot drill, so we have to drill out the cylinder end of the 3.2mm drilling to 5mm with enough depth for the nozzle to screw in but the only way to do this is to do it from the top of the bore with a really long drill! I went on eBay again and bought and extra long series 5mm drill for the job. This thing is 250mm long and looks absolutely ridiculous in a cordless hand drill.

It actually looks more like it should be used on masonry but these have the normal tip and are actually for metal. If the one you buy has a flat ceramic insert in the tip you’ve bought the wrong one!

I suggest you mark the depth you need to drill to accommodate the nozzle thread (with a little extra room for tapping) on the drill bit. The actual depth here isn’t critical as long as there’s enough depth for the nozzle threads at a minimum. Again plenty of lubricant and drill with slow speed and light pressure and be very careful to keep the drill loaded straight otherwise at best your hole will be at a funny angle but at worst you may snap the drill and damage the bore surface.

Next clean the swarf out again so we can get a good thread tapped. Tapping the holes is another slightly awkward problem for the same reason as drilling the pilot hole, we need to do it from the top of the bore. I suggest going on eBay (or any of a thousand other places online) again and looking for an extra long ratchet tap wrench. These are available under any number of brands but I suspect they’re largely all from the same place. They are available in a small version, which is 250mm long and will tap M3-M10 or a large version which is 300mm long but taps M5-M12. I went for the smaller one because the smaller chuck should allow tapping tighter to the cylinder wall without damaging it and this is likely to be tight for this task. Expect this to be about £10. While you’re at it buy an M6x1 plug (bottoming) tap!

Again proceed slowly with a well lubricated tap, many people will say you need to use proper cutting compound but for a small hole in a soft material this isn’t necessary, 3in1 will be fine. Try to cut forward a bit (maybe a turn at a time or so) and then back the tool off until you feel it turn smoothly. This will help prevent the tap from clogging up and either seizing up or damaging the new thread by material being forced against it. It may be necessary to back the tap out entirely to clean the removed metal from the threads because this is effectively a blind hole. Be careful not to keep going once the tap bottoms out. If you aren’t careful it’s comparatively easy to strip the threads in the aluminium with such a small tap and then it would be awkward to repair. If you’re not confident this really isn’t an ideal job for anyone new to tapping because it relies on having a degree of ‘feel’ about what you need to do and when to stop.

Rinse and repeat five more times and congratulations you now have six neatly drilled and tapped jet positions! Before doing anything else clean everything again, I used a combination of brake clean, compressed air and a scribe. You need to make sure there is no swarf left in the drillings so you don’t risk that jet becoming clogged. Once clean you need to fit the jets. The jets I selected have an external hexagon and so can be tightened up with a socket wrench but you will need sufficient extension to reach the bottom of the cylinder bore with an appropriate sized socket. Clean all the jets with brake clean to degrease them – technically this is not necessary but it helps remove any other grime that has become stuck to the jets in manufacture/transit. Next I recommend you apply a small dab of a suitable thread locker to the jet threads, specifically I went for Loctite 243 which is a medium strength thread locker which will resist oil. You can use others but if you go for anything stronger you’ll need a blowtorch to get it out and trying to do that down a cylinder bore could be interesting! Once you have the dab of Loctite on the jet you need to screw it into the newly tapped hole – I found it easiest to do this carefully from the crank side of the block by fingertip but your mileage may vary! Once you have it in enough to keep it in place tighten it in with the socket wrench. The jets will only need to be nipped up for two important reasons; firstly they are thread locked and so will not vibrate loose and second they are small and made of brass so any more force will likely strip the hex.

That’s it, one new set of shiny piston cooling oil jets! More on this project coming soon!