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…

£4 eBay coffee table


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.

Glass coffee table refinishing rig


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.

Head with worst of gasket scraped off


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 during degreasing
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 GritUK Grit Ra µmRa µinch
 P1203125
 P180285
80 1.6570
 P2401.550
 P3200.7530
180 0.6225
240 0.4518
 P5000.415
320 0.2510
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.

Head surface reflection

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:

Modified RX8 bearing retainer

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.

Mondeo mk3 concentric clutch slave

3D model of Mk3 Mondeo Clutch slave

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 :

3D design of first adapter design

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!

Clutch slave adapter Mk1 in steel

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.

RX8 gearbox refitted to the car

And all back in the car…

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

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

Wire feeder
The new wire feed motor

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.

Wire feed drive comparison

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.

Migmate 130 of feed removal

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.

First cut for wire feed

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

Front first cut

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.

Wire feeder trial fit

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.

New feed roller

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.

Mounted new wire feeder

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!

Fully fitted wire feed and reel holder

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

New 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.

Dinse connector
Make sure it’s all tight; you don’t want this coming loose!

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

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.

Migmate 130 Feed Mod

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.

Added power supply location

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 :

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.

3d printer nozzle

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.

Extra long Series 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! 5mm Drill Jet

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.

5mm Drilled hole

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!

Tapping the Jets

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.

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

RX8 Project – Part 15, Engine Strip #2

So having removed the timing chain and tensioners (see part 1) next we need to start looking at removing some more major parts of the engine.

Having already removed the cam covers already you should be looking at something like this:

Jag Cams

Thanks to the Jag Motor Project for the image – hopefully they don’t mind me borrowing it! It seems I have misplaced my own photo of this!

You need to remove the cam bearing housings because the design of this engine has the head bolts directly under the cam making it impossible to remove the head with the cams still in place. This is worth remembering and is at least part of the reason stretch bolts are used for the head – it is impossible the re-torque them after an interval of use without removing all the timing gear. As you can see in the photo these are three smaller housings and one larger one at the front each held on with two small bolts. Basically you just need to carefully remove these bearing housings in order. I suggest marking the direction and its position on each one before removal. The position could be achieved by putting each into a small tub which is numbered. However you do this you need to know which is which and which way round they go. Remove them carefully and make sure you don’t drop any bits! Once you have removed the housings you’ll see this:

S-Type V6 Cams Removed

Now we have clear access to the head bolts which as you can see in the photo there are eight of. These are fairly easily removed except for one thing – the bolts are set well down into the head and there is very little room in the recess to put in a socket. You will need a 15mm socket for these bolts and a small breaker bar (or an impact gun) as they will be quite tight.

These bolts are not reusable – I mean you can but it’s a terrible idea particularly in such a critical location because odds are high it will not be up to the job. This is because “stretch” bolts rely on the material of the bolt reaching the yield point of the material at which it begins to exhibit a fairly constant elastic stretch. In effect once they start to deform they behave a bit like a very stiff spring and so if tightened correctly will hold a very accurate load without loosening and so do not need to be re-tightened after a run in period. That said hang onto them for now so you know what to order to replace them!

S-type V6 Head bolt removal

You can see how tight the casting is around the socket! Once all the bolts are gone you can lift the head away. It might take a little persuasion with a mallet. Make sure you have a suitable clear space to put it on once you remove it.

Now you should have this level of grime:

S-type V6 Head removed

Obviously you can just pull off the head gasket now to improve the situation quite a bit and you can have a good look at the state of the engine:

S-type V6 Factory Hone

Here you can see the cylinder bore actually looks in very good condition and even still has the factory honing marks on the bores which is a good sign it’s been working well and shouldn’t have suffered wear issues.

Now do all of that again for the other head and you should have something that looks a bit like this:

S-type V6 Heads Removed

Congratulations now you have an engine with no heads but since my plan was to upgrade the rods I still needed to remove more so flip the engine over and we can get to it.

S-type Oil Pump

In the picture you can see the oil pump is just held on by four small black bolts. I put the crank bolt back in place just so I didn’t lose it but you would have removed this a long time ago. Once the four small bolts are out the oil pump can just be slid off the crank and put aside.

S-type V6 Front Oil Pump Removed

 

Next we need to remove the con rod bolts and this is where having the crank bolt comes in because you can put it back in finger tight and once it snugs up a bit you can turn over the engine to get access to all the rod bolts. Mark up each rod with a cylinder number and arrow for the front of the engine. I put sharpie marks across the split line of the rod to make it easier to match them up later. I had to use something to knock the piston out of the bore use something non metallic otherwise you will likely damage a surface you don’t want to damage. I used a length of wooden dowel. Do these carefully unbolting and removing one at a time. When knocking the piston out don’t forget to catch it before it falls on the floor!

S-Type V6 Oil Pump Removed

So all we have left is the crank. If all you wanted to do was straight swap the rods this is as far as you need to get. Well I wanted to do a few other while I was at it (more on this in another post) so I carried on to remove the crank. This is actually pretty simple at this point, you just take out the 16  main bolts holding the lower block to the upper block along the bearings. The other thing you can see in the picture are the engine mounts, the rubbers here aren’t stock s-type, they’re actually from a V8 Land Rover (Discovery among many others). The reason for this is they’re very strong, extremely cheap (£7 a pair delivered from eBay) and have a stud each side which will fit straight onto the factory cast aluminium mounting arms and also make mounting onto the car really easy when we get to that stage!

S-type V6 Lower Block

It’s worth noting in the above picture not all the bolts are the same. This is because some have small studs on the top to allow the windage plate to be mounted (blue). Note which goes where so this can be put back later! Next you also need to remove the 6 outer bolts (red) before the block will separate.

S-Type V6 Lower Block Bolts

Once all the bolts are out again you might need a gentle tap with a mallet and/or a scraper to get the block apart. Don’t drop the crank bearings!

If you’ve done all of this you should have something a bit like this in front of you:

S-type Stripped 2.5 Block

And a heap of bits you just removed:

S-type Engine Parts

More to come on this project in my next post!

RX8 Project – Part 14, Engine Strip #1

After deciding to turbo the engine (see earlier posts) is became apparent I would have to upgrade the piston rods to make sure the engine wasn’t in danger of these failing and ruining the engine. This meant I needed to extract these from the engine Now bear in mind that this was the first time I’d ever taken the head off and engine before let alone removed a crank so it was likely to be quite a long and delicate process! Also accept that I was making this up as I went along, things may be in a strange order but it seemed to work!

First things first mount the engine to a suitable stand:

Here it is, it’s already upside down but that doesn’t matter! First off I took off the sump. On this engine it’s a cast alloy unit with a large front bulge which makes working around the front of the engine more awkward so I got it out the way early on.

V6 Windage tray

Take off the oil pick up pipe (2xM6 bolts) to get room for the windage tray. The tray is held on by 5 nuts on some special studs on this engine, these are M10 one side to hold the lower block to the upper block but i think M5 on the top just to hold the windage tray.

Duratec V6 Bottom

Now we have exposed the moving parts of the engine and get the first look at the bits we are replacing but there’s a lot more before we get them all out. An interesting thing to note here is the absence of crank bearing caps. On this engine the block is formed in two cast pieces which joint along the crank centre line so the crank bearings are held in place by the substantial cast ribs you can see in the picture and each bearing has four M10 bolts to keep it in place with additional bolts around the outside of the casting.

Next move to the front of the engine and disconnect the hose from the block to  the water pump then unbolt the water pump. On the Ford version of this engine the water pump is driven directly off one of the cams but on this Jaguar one it is a separate unit driven from the back side of the accessory belt and is held on by three small M6 bolts. Next up remove the crank bolt, there are a variety of ways to do this (the easiest probably being a decent impact gun but at this point in the project I’d not yet bought it) but the method I chose was to block the rotation of the crank using a block of wood. This is done by finding a suitable block that fits between the crank and the housing such that as the crank counterweight rotates round it is stopped by the wood. Just remember that the crank bolt undoes anticlockwise so make sure you put the block on the correct side(the bottom in the above image)!

S type V6 front

Now you can flip the engine back up the correct way because we’re moving on to the heads This is because the cam covers need removing to take off the front engine cover.

S-type V6 Black Cam Cover

This bit is again very simple, remove the bolts holding each coil unit in place. Again this being the Jaguar version of the engine is came from the factory with coil on plug. Next remove all the bolts around the cam cover and lift the cover away. Sometimes these get refitted with instant gasket to fix a failed cover gasket cheaply and quickly and so it may require some persuasion, I usually use a putty knife or a wallpaper scraper for this job but it can be easy to damage the faces if you’re not very careful. Alternatively plastic trim removal tools can work well. Obviously repeat the process for the other cover.

Next up we need to remove the front engine cover. This involves removing the bolts all the way round the edge, you can’t miss them, there’s loads and they’re all the same! Make sure you get them all, I think there’s 17 of them but don’t quote me on that, one is under the belt tensioner by the crank! This cover again might require a little help coming away due to the gasket but should be relatively easy. If it isn’t then you’ve missed a bolt so stop prying it!

S-Type V6 No Front Cover

It should look something like this! Now you can see the other feature these jag engines have – variable valve timing on the intake cams. An important point here is the crank timing wheel (the notched wheel on the crank). These have two key positions but only one is correct so carefully mark which position lines up with the key on the crank when you take it off. I recommend something permanent so when you clean all the oil residue off the mark is still visible, a centre punch mark should do it.

Next you need to remove the timing chain tensioners. These are small hydraulic cylinders that use engine oil pressure to maintain tension in the timing chain. They are held on by two bolts each. Just undo the bolts and carefully remove the tensioners from the tension arms.

S-type V6 Timing Tensioner

Once the tension cylinders have been removed the tension arms can be lifted off their dowels and removed as well and then the chains can be lifted off and you should have something that looks a bit like this:

S-type V6 removed tensioner

Now all that is clear the chain runners can be removed. These also hold the VVT solenoids and so are quite a complex bit of metal but are easily removed. I also took of the water hoses at this point just to simplicity.

Now you should be at this stage:

S-type timing gear removed

In the next part the engine strip will continue…

RX8 Project – Part 12, Turbos #3 – Flanges

This is a step that most people won’t need to do. Or rather there are usually easier alternatives to! When most people build a turbo manifold they simply buy pre-cut flanges for both the inlet and outlet and weld them onto the ends of whatever intricate bit of welded pipework they have devised and all is well. This is fine for the vast majority of turbos currently available but what if we have one that’s a bit more unusual, say one that most people would never even dream of using for a custom setup. For example the custom housing GT15 turbo used on a diesel Rover from about 20 years ago. That would present more of a challenge! Why do I never make these things simple!

So what we need to do is make some flanges, this isn’t a technically complex task but does take a little thought.

The first step is to carefully measure the size of either the fixed studs (or bolt holes). These are commonly M8 and so the bolt OD will be just under 8mm and if the flange has the holes will be more than the bolt size as they tend to be quite generous to aid alignment. M8 clearance hole might well  be as much as 9mm but note these all down.

Next measure the distance between each of the holes/studs, adding half of each hole/stud diameter on these numbers will give you the distance between the centre of each fixing position. This gives the fixing positions and would allow a template for these to be drawn. If doing the job this way you just need to measure the main port diameter and its distance from the centre of each hole/stud position to the centre of the port. In my case one port was handily central in a triangle so I could just measure half way between each pair of stud and draw a line to the third stud and where they cross the port centre goes.

I also tried another approach which involved taking a thing piece of aluminium and physically imprinting it with the studs using a mallet. This can be handy for really irregular patterns but does mean you don’t have a nice dimensioned drawing to keep, but you do get an aluminium template. Basically you take your aluminium, lay it over the studs and tap it with a mallet. This leaves an impression for all the fixing positions. What you’d normally do here is just drill a small pilot hole where the centre of each stud is to use to mark up your steel. in my case I didn’t want to have to remove the studs from the turbo so I drilled them out full size.

Flange Template

At this stage I used the same method to indent the sheet metal for the port which was then drilled with a 3mm hole for later transfer.

The port mark was critical because the port was the largest hole and most likely to go wrong! After marking it up on the 10mm thick steel plate I was going to use as the flange and looking at my pillar drill I decided I needed a substantial clamp for safety! While I could have bought a suitable clamp kit I decided that since I already owned suitable tee nuts for the bed I could make it safely.

Port Drilling

So this was the final drilling arrangement – and yes that is a hole saw! I feel at this point I should point out that not all hole saws are created equal. Most commonly found at DIY shops are only suitable for wood/plastic/plasterboard and maybe aluminium sheet which not unreasonably are the sort of things used in DIY. Proper tool shops will supply hole saws rated for steel but they will cost a little more the set I used was this one. It’s certainly not the most expensive out there and probably won’t last terribly long with this level of use but it’s rare I use them for anything like this and I can replace the individual saws in the set fairly cheaply.

You need to centre punch where the port centre is to locate then mount the plate onto the drill. Put a smallish drill bit (don’t go really small as you risk breaking it, I started at 3mm but you could easily go a little larger as this isn’t really precise work)  into the chuck and carefully align the punched mark on the plate with the tip. Once you are happy with the location tighten the clamps down. Tighten a little each side at a time if you have an arrangement like mine as otherwise the high pressure on one side will tend to make the place slip out of position during tightening.

Next you need to lubricate! This is absolutely critical drilling metals otherwise you will spend a lot of time either sharpening worn drill bits or trying to extract broken ones! There’s a lot of debate on whats best, for most light work I use WD40 but you will get through it quite quickly as it will tend to vaporise with the heat, this is good in that it helps cool the metal and cutting tool but it must be replaced with more. With deeper holes or larger diameters I tend to use 3in1 as it seems to work well. For the hole saw here I actually started using car gearbox oil, this slows the cutting but protects the tool.

Once you have a pilot hole swap the small drill bit out for the hole saw, make sure you have the speed slow, cover everything in lubricant and gently start to cut. This will take a considerable amount of time, be patient and regularly stop the drill and clear the cut debris away from the saw. Try to avoid using your fingers to do this as the edges can be very sharp. An air compressor is great for this but I have found that cans of computer air duster work pretty well.

Once you have your main port drilled remove the plate from the drill and file back any sharp edges then use your template to mark the centres for all the other holes, these will then need to be centre punched as before and drilled out to size in stages, I went 4mm, 6.5mm, 8.5mm from what I remember. The only critical one being the final size with the earlier steps being arbitrary. If smaller increments are used the cuts are normally quicker and easier but it adds more operations and so will likely take longer. Also I drilled all the stages on a single hole and then moved the plate which adds many more drill changes but you could also drill all the holes to one size then change drills but this has the added risk of the alignment being off which increases the chance of the bit chattering and potentially breaking but can be done if you’re careful. For the level of precision we really need it doesn’t really matter.

Rough Cut Flange

By now you should have something a bit like this! At this stage with the new flange seated in place marking the outside edge of the flange becomes much easier – you simply bolt the flange in place and draw (or even better scribe) round it on the mating side. The flange then needs to be removed and trimmed back to the mark. I rough cut the bulk off this with and angle grinder and then tidied the edges back with a bench grinder. Again working 10mm plate takes a little time but it’s not too bad and the outside edge doesn’t need to be perfect just not look silly or clash with anything and still be wide enough to hold a gasket.

Turbo Flanges

Here’s the result, two respectable looking turbo exhaust inlet flanges. The process for the exhaust outlets was exactly the same but the main port was 55mm diameter rather than 36mm diameter making the process take even longer! If you’re in a hurry get them laser/waterjet cut!

In another entry I’ll be looking at the process of making the custom exhaust gaskets I need to match.