Measuring up the lower wishbones

First step, measuring the length of the rear lower wishbones. A fairly simple process, let the uprights stand vertical, the CV joints sit comfortable (not under tension or compression), then measure from the centre of the bottom fixing to the centre of the wishbone bracket;

And the magic number is 375. So I can compare that to an existing Saturn design;

That shows 395.8 from edge to edge. With a wishbone tube being 33.7mm wide, that means mine are longer at 408.7 from edge to edge. Unfortunately trying to get it down to 395.8 seems to compress the cv joint a bit more than I'd like (and as the suspension moves it will compress even more). I repeated the process on the other side, it actually sits 5mm shorter, but any reasonable amount of camber and the driveshaft binds on the diff.

I also measured up the metal. I have 2490 of tube, and based on the 375mm length, I need 2420 of metal! So no room for mistakes! I'll be using 19mm for the top wishbone, same as the Sierra design. This is because the suspension mount isn't on the wishbone. I'll still brace it a little bit, but at least I won't need the thicker tube.

Driveshafts and uprights

The diff is in place, and the driveshafts, and the uprights. And now I have a problem...

I had planned to fix the coilover alongside the upper fixing of the upright, like the Westfields do;

But with the coilovers at maximum extension (13 inches) the driveshafts are horizontal. Which means as the suspension compresses, the driveshafts will be angled upwards. I don't think this is a good thing. Even comparing to the picture above, I would more expect the driveshafts to be horizontal under full load.

So time for yet another rethink. I may try and mount the coilover top near to the edge, but that would need some reinforcement on the plate.

Mmm, I've just noticed, the uprights are backwards in the Westfield...that could be useful...

(Later that night...)

I've also just noticed that the upper mounts on the Westfield aren't mounted to the upper plates, they're mounted to the cross member. The hole for putting the bolt in is actually in the back seat panel. The plate is only used for the rollbar. So I'm thinking, if I reverse the uprights, mount the coilover as per Westfield, it would be mounted an inch or so down and out so the shorter shock wouldn't matter anymore. There's a little bit of bracing added, I can do the same.

Looks like I have a few things to try out tomorrow! :)

More diff...

I treated myself to some new welding gloves, mainly because the right index finger was so burnt it bent sideways instead of inline with the knuckle... anyway, long story short, turns out it's the way I hold the torch as I weld, because the new pair did exactly the same thing after welding the diff brackets!

Anyway, on to the diff.

Once the upper bar was fitted, I used offcuts of the old Sierra diff plates that I had from a guy on LCB. He was getting rid of a nearly complete set of plates, a few bob for postage and a bit extra and they were mine. Obviously the Sierra plates were never going to be used, but the holes were the right size and it's thick enough metal. A quick trim and the brackets were produced. Note the bottom left one in the picture, that's to avoid what was the PPF bracket on the diff.

The diff seems to fit quite well;

Obviously the diff is mounted centrally according to the driveshaft flanges rather than the propshaft. I was always going to have a 'wonky' propshaft as the diff isn't centred. This wasn't going to bother me, I just had to make sure that the prop had enough clearance;

Yep, looking good to me. The more observant of readers might notice this 'after' pic only shows the tack welds, rather than the full welds of the 'before' pic above. That's because this was me trialing the diff fit before fully welding.

So once the plates have cooled down, I can bolt the diff in place and then mount the driveshafts and uprights. Then I can figure out how things will fit together!

It's nice to make some progress though... although looking at the picture above that propshaft really needs cleaning. It's got to be cut to length anyway so I'll get them to check the bearings at the same time.

Rear suspension

I keep putting it off because I just know it's going to be a nightmare. The whole thing is going to be a mishmash of all books, and plenty of scope for mistakes. I'm even changing the upper wishbone completely, just to make it fit better and get the loads flowing in the right directions.

So, first thing, mount the diff. And it's not a light diff either;

At least I'm going back to the gym so getting in and out is getting easier!! By the way, it probably looks a bit different to a standard diff, it's got the Talon diff cover, then two coats of red oxide primer, then two coats of satin black top coat.

I should actually mention that nothing on my car will be powdercoated, I do like the look of it but I've come to the conclusion that whatever I do, it's going to need repairing, and powdercoat doesn't repair!

So, first step, lower and upper braces for the diff;

(upper to be added, erm, when I get round to fitting it!!)

How time flies!!

Well, I finally got the wishbones finished, I reckon at least 20 hours labour start to finish for all four front wishbones.

Same as before, start with a layout;

And end up with a wishbone!

OK, I skipped a fair bit of effort, and this is only at the tack stage, but to be honest the uppers did go together a lot quicker than the lowers. Again, there's a gnats hair difference between the two.

I had some old tube to hang them all from, so first was two coats of Screwfix red oxide primer;

Then two coats of hammerite copper;

And then fit the polybushes (I didn't need to do this stage, but it felt good to see them slot in perfectly!)

I also got all the front brackets fitted. To be honest, I expected this bit to be much harder than it was, but thanks to the advice of Phil from Talon my front frame had been welded up to host the brackets from the start. Everything just fell together, face against face and welded perfect.

Note the reinforcement behind the front upper wishbone bracket. It's just a triangular chunk of square section welded up, not overly pretty but it gives me confidence that it will stay put!

I do like some of my welding, although other parts are a bit messy. They've all got very good penetration, almost too much in some places.

The wishbones fit beautifully into the brackets, and the coilover bracket is perfectly in line. Very very happy with the front suspension. On to the rear.... again...

Front upper wishbones

The front upper wishbones should be a bit easier than the lower ones, smaller thinner tubes and no plates. However, there were two measurements I needed to sort out first.

Number one, the angle of the insert. I now have two inserts that have been welded inside a 25mm tube. The tube itself is 50mm long, so comparing that to the plans means I'm 5mm narrower and 10mm shorter. So all the measurements on the wishbones go out the window! To get the insert angle still at 8 degrees, I had to work out how many spacers I needed. A quick bit of trigonometry left me with 7mm of spacers required at the end, to give me an 8 degree angle.

Number two, caster angle. I'm not going rosejoints at the moment, mainly because I'm not building 'that' sort of car. I will keep an eye on rosejoints as an upgrade, but not for now. Which means I have to get the caster angle right first time, and the asymmetrical wishbones are the perfect opportunity. I am aware that 'the book' has messed up the calculations, and only gives 3.5 degrees rather than 7 (although I think this is the '£250' book rather than the 'on a budget' book). But I'm not going by 'the book', I'm mixing up various sources. So I had to work out what was ideal.

From various forums, I have 10 degrees as being a good start, so as close to that as possible. Given the measurements in the book and on my own wishbones, I worked out that with the upper wishbones as they are in the book, I would get 7 degrees camber. With the Saturn measurements, I would get 6. Yes I know it's not quite 10, but the higher the better so I'm going with the book measurements. This means an offset of 120mm for the centre of the insert.

And that's where I ended the day. The jig was sanded down ready for a new set of markings, the thin tube is ready to be cut, and my forearms are ready for a shedload of hacksawing.

Front lower wishbone build

Some photos!! First, the plates between the wishbone tubes. This was cut from 5mm plate with a standard jigsaw and some Bosch blades. Plenty of cutting fluid, and several hours later, I had this;

Next were the tubes themselves, just cut to length and then manually profiled to the bush tubes;

As the lower wishbones aren't handed, I did them all using this jig. That way I knew they would all be identically right (or identically wrong!). The plates I had cut for other parts of the suspension came in very useful as spacers, I kind of ignored the spacers suggested as it didn't leave all the seams in the centre. And when I was welding I wanted to make sure I was welding on welds.

Then came the bottom cut. First I tried marking it with a laser beam;

But I couldn't get it to line up perfectly, so I went for an old fashioned handsaw jig. Again, lots of hours and lots of cutting fluid later, I had all pipes cut, and a full set of parts;

A first fit showed a bit of trimming needed;

So ten minutes with a flap wheel on a grinder got them fitting perfectly. Straps and clamps aplenty ready for welding;

And a short time later I had two wishbones!

Putting them back to back showed that there was less than 1 millimetre difference between the bush tubes and the balljoint fixings, so I'm really happy. 

I just have a couple of holes in the end of the tube to finish off, but I might pour some waxoyl in there first. It'll probably all get burnt away as I finish the weld, but at least things will stay rust proof.

The cut tubes left an interesting profile, which got me thinking about the next stage. I need to sleeve the threaded inserts for the top wishbones, and I was advised to cut the sleeve at an angle to maximise the weld length. As it so happens, the sleeve tube is the same tube I used here!! So;

The two on the left are bare offcuts, the two on the right are the inserts welded into place. With them fully welded as they are, the BMW balljoint still fits perfectly. Tomorrow I'll grind down those welds, and put the other two offcuts on top. Once they're welded on, I'll have a completely sleeved insert with good welds holding it tight. It's still only 50mm long (the original plans call for 60mm) but the threaded part of the balljoint is only 50mm long so I'm not worried.

Front suspension build

The front suspension is now coming together. I'm taking the MX5 measurements from the Saturn plans, but I don't want the lower adjustments. So I've kept the ball joint where it is, kept the bushes where they are, but brought the wishbone tubes out to between the two. So far so good, although cutting and shaping the fish mouths (is that the correct term?) has been an absolute ballache!!

But before I continued, I want to check what sort of suspension measurements I was going to get. So for camber, I have worked out the following (assuming horizontal suspension at rest);

Upper suspension distance from end of studs to the end of the wishbone (where the balljoint screws in) = 192mm.
Upper wishbone length from end to end = 242mm.
Total upper length (end of wishbone tube to end of studs) = 434mm.

Lower suspension distance from end of studs to balljoint bolt = 130mm.
Lower wishbone length from end to end = 410mm.
Total lower length (end of wishbone tube to end of studs) = 540mm.

On the chassis, the brackets are mounted as follows;

Upper brackets are 335mm from centre.
Lower brackets are 247mm from centre.

By my reckoning, that gives me distance from chassis centre to end of studs at 769mm upper and 787mm lower, a difference of 18mm. A rough calculation suggests this is a 5 degree camber, so I'm going to have to get it down to 4mm for a 1 degree camber (ideal start). I don't expect this to be an issue with plenty of space available in the adjustment.

I'll work out caster tomorrow, aiming for +6 to +10 so fingers crossed for 28mm difference top and bottom!

Post Christmas update

Yes I know it's February, and yes I know my last post was September, but that pretty much sums up the build to be honest. It's been dormant for about four months for various reasons.

Anyway, lots of updates;

Phil at Talon finally got me a new diff case, and it fits perfectly. He's also suggested a few things for fitting, mainly so I don't actually damage the casing while it's being fitted. I've also figured out that the two plates that I had for a Sierra diff can be chopped up and will become the fixings for this diff!

The casing arriving does mean I was able to crack on with the rear suspension frame, and that's all welded up. Well, on that subject the whole chassis has now been fully welded, and I'm really happy with the results (even if it took more than twelve months!). I am a bit short of metal now though, I don't have enough for the extra triangulation. At some point I'll pick up one more 1" section and a 3/4" section.

I also popped over to theflockkeeper (Ebay person) in Telford for some steel offcuts, and came away with a good selection of 1mm for panels, 3mm for brackets and 5mm for suspension parts, all for the princely sum of £60. I still haven't got a floor but I've got pretty much everything else. Now I have no excuse for putting together the wishbones!! I won't be panelling in the engine bay, I'm working on the assumption that it will have a full bodyshell over it so the panels are redundant. It might help with cooling as well.

I managed to run out of welding gas while doing the chassis, a quick journey to my nearest Hobbygas supplier got me a full tank for £30 + VAT. I'm really liking not having to pay rental on the cylinder! I've got through at least three rolls of welding wire as well, I would go bigger but I've heard problems with the bigger rolls and it's not a huge difference in price.

Another bargain found as well, a fellow LCB member sold me a full set of coilovers for £100. Platform and damping adjustable, they just need a bit of a clean up. They even had the spring rates written on the springs! They were off a locost chassis rather than a Haynes chassis, but I think the lengths are ok. The front look fine with good spring rates, the rears might need stronger springs and perhaps a modification to the mounts for the length.

So the next stage is wishbones and mounts... See you next year (probably!)...

Oh, and one last thing. I'm using a 1.6 MX5 as a donor, and as any MX5 owner knows, there was a design flaw with the crankshaft (google short nose crank for more details). So I decided to check before I got too much further with the build. Turns out I have the updated crank with the better fixing, so no self-detonating engine for me!! Yay!

Disappointed/frustrated

Well, I expected at least one downer on this project, although I did expect it to be DVLA induced. After removing the diff, and cracking it open, I've found it doesn't fit on the Talon diff cover. The mounting holes are on a circle that's approximately one inch wider than the diff. They're in the right place in terms of angles around the centre point, the screw threads are correct and the two stub axles fit nicely, but there's no way the diff is going in. I do wonder whether it's a difference between a 1.6 and a 1.8 diff, as the one in the picture is a 1.8 but mine is a 1.6.

I've emailed Phil to see what happens, I'm not sure what he can do though. At best a refund would leave me just out of pocket for the postage and packaging, but then unless he can make a new one to fit I'm going to have to go back to the original plans for the rear suspension. Which was what I was trying to avoid!

There might be a possibility that I can use a 1.8 diff, but keep everything else. That's if they bolt together...

Well, there is an update, rather quickly actually. Phil is putting together some CNC created covers, so hopefully I can arrange with him to swap my prototype one for a 'real' one. It should also fit the 1.6 diff, so win win really.

Oh yeah, and I've figure out my diff is a viscous LSD. Not as good as a Torsen diff, but better than a completely open one.

We have lift off!!

Everything stripped off the car, all bolts undone, and engine stand in position;

Take the strain...

And lift...

Rear wheels moved to where the front wheels used to be;

And done!

There was a slight miscalculation with the length, the exhaust hung outside the garage. So a bit more spanner action and the exhaust was off!! It was way too big to reuse, so the scrap man got that one.

So the garage is now full of wanted kit...

As well as unwanted kit...

So it's time to start getting rid of the unwanted bits. Everything went on MX5nutz first, a few nibbles but nobody local who could collect. And none of it can realistically be delivered. Over to Gumtree, and the wing mirrors and soft top have already gone, so that's £100. The panels are still to be sold, so fingers crossed. If not it'll go to Ebay, but I suspect that will be hard work.

Nothing else will happen with the build for now, with all that stuff in the garage I can't move. But I'm off to Ireland for a couple of weeks, so it will just stay there. I hope the empty shell can be removed before I go, I did have one place that wanted scrap metal but when I phoned them I found he'd moved to North Wales. Fingers crossed I find someone to take it.

Chassis build

I've just noticed, I got so distracted by my donor strip that I hadn't logged my progress with the chassis. So the tunnel is done;

I did have a bit of trouble with the diagonals on the seat back. For some reason I'd cut them identically, but where they met the suspension top mount on one side, it was a good inch or so off on the other side. I actually left this one for a couple of days, so frustrated with myself that the chassis was that twisted. I'd measured everything as close as possible with my eye, each of the horizontal bars on the rear were identical and the verticals were a perfect match as well. But of course, same length on parallel sides either makes a rectangle or rhombus; the former being good and the latter being bad.

I finally came back to it and had a good look at what I was doing. Then I found the problem. The horizontal bars are at different angles, the middle one being 'flat' to the seat back and the top one being horizontal. This means that the diagonals are cut at quite a sharp angle on either end, with a 'diamond' profile being presented to the top bar. I'd basically been measuring the wrong part, the wrong end of the diamond. Once I started comparing the centre of the diagonals rather than the corners, it all lined up. I now have a matching set of welded in diagonals, and there is roughly 1mm difference between the two. That does suggest there is still an element of error, but 1mm is a huge improvement over 1 inch!!

I'm quite happy with how the diagonals have gone in all over the chassis to be honest, I cut them all as matching pairs and they all fitted correctly with no trimming. That means that with the laser alignment checking the horizontals, the verticals are similarly accurate.

Anyway, enough chassis waffle, the MX5 is nearly stripped and might be losing it's bodyshell this weekend, so it's all steam ahead for getting the last few donor bits off the car!

I think I've found it!!!

I've spent ages now, trying to figure out how to build the wishbones. And it looks like I've finally found all the necessary elements.

The top track rod end will now be from a BMW, or to be precise an E34 BMW 5 series track rod end. These have an M14 x 1.5 thread, so I'll need to get inserts to match. But at least they're not £10 each! 

Anyway, now that has been sorted, I can finish stripping the donor. I'm nearly down to removing the shell, then I can wheel the base into the garage and get my drive back!

More suspension

OK, starting to get the locations together.

aksteel92 appear to be the only people who do 33.7mm x 2.6mm, 1 metre for £15.73 (including a tenner P&P!). I can get individual tubes for a pound each, but for around £2 each they get expensive quickly. And this way I can cut them to fit the crush tubes.

10gbottles do the 19mm and 25mm with a total cost of £45.16. However, if I keep all wishbones as 25mm, metals4u do 6 metres of 25mm for £35.40. A tenner cheaper to have thicker top wishbones.

Threaded inserts from Rogue Engineering, M18 x 1.5 in pairs for a tenner each. I'll need six in total, two for the front top adjusters and four for the rear lower adjusters. This will mean I move to using the transit ball joint instead of the BMW one, so I'll have to buy the reamer as well. Still better than trying to find an M14 insert! CW Fasteners appear to sell M18 rod which would suffice as adjusters for the rear (emailed to get a price).

Looks like another £100 just for wishbone metal, and I've not looked at the plate metal yet!

Boot wiring

The boot wiring is relatively simple, everything coming from the same place (well, apart from the fog light wire!);

From the wiring loom outwards, there is;

1. A long reinforced wire for the bootlid brake light

2. Left hand light cluster connector

3. An unknown 2 wire connector

4. Left hand number plate light

5. An unknown 4 wire connector

6. A ground wire

7. Right hand number plate light

8. Right hand light cluster connector

The two other 'white bits' are the chassis fixings rather than connectors. The last black wire on the right is the fog light wire, that is wired up on it's own all the way down the right hand side of the car;

I've removed the fog light wire from the connector so I can withdraw the loom, it might go back in but the cluster fog light is not 'e' marked so I think I'll need to fit a proper fog light.

Interior strip part 1 - Wiring

Nothing challenging so far, just a few pictures of the wiring so I know where things have come from;

Drivers side wiring. Bottom left is an unknown connector, from near the seatbelt mounting. The other part of this extension is for the seat speakers, and in the bottom left is the push pin for the door (possibly only for the alarm).

Passenger side wiring. Same again, bottom right is a mysterious unconnected wire from the seatbelt fixing, then the speaker connection. The passenger side also had a separate dust covered connector, I think that is for the rear window demister for glass windows.

Centre console wiring. Not much here, a connector for the electric windows and just to the side of the gearshift is a light fitting for the ashtray. There is also a push connector for the handbrake, again probably only needed for the alarm. The middle wire still attached to the chassis looks more like a factory fit, but it's not the fog light wire as I found that on the right hand side.

On both sides of the loom, there is a connector for the seat belts. Apparently JDM cars (Japanese Domestic Market, IE Eunos!) have a 'feature'. With the ignition on, there is a solenoid that prevents the seatbelt retracting all the way in. I have to admit, that is quite possibly the dumbest 'feature' ever. A knowledgeable guy over at MX5Nutz suggested the feature could be turned off by removing a fuse. Basically I'm going to remove the wire! The wires down by the seatbelt stalk are similarly useless, so they'll be removed as well.

Looks like the entire loom comes down the drivers side into the boot, then the bits on the passenger side come out of the boot. It's raining at the moment so I didn't have chance to remove that part of the loom, but it would make sense to be the next thing to do.

I have a donor!!

Well, I've finally got myself a donor, and a rather nice one to boot. In fact, so nice there was part of me that didn't want to chop it up...

But chopping up will happen, so it's time to start a shopping list. So I will be keeping;

The engine (obviously), gearbox, propshaft, diff, driveshafts, all uprights all brakes, and wheels.
Seats (lovely aged tan leather, should look perfect).
Air vents (chrome surround, the only bit of chrome that I like the look of)
Instruments and switches
Front and rear lights
Full loom and ECU
Pedals with brake cylinder.
Handbrake

I will be selling;

Bumpers (maybe, might be difficult due to the size)
Wing mirrors (£50 average price on Ebay? They're ugly!)
sill covers (nice chrome roadster plates, should get something)
Hood (I was going to try and use it, but it just looks too wide)
Wings, doors and bonnet (again, the size may make it difficult)
Mats (they look really old, but they are v-spec marked so they might have value) Edit: On second thoughts, they won't sell, so bin unfortunately.

I will be binning;
The alarm (blasted thing is a right royal pain in the a$$, and I have a feeling it's going to have damaged the loom unfortunately)
The main body
Boot lid
Carpet (I did think it might sell, but doesn't look like it)

I'll strip the interior first, then work outwards. With any luck I won't have half a car sat on the drive for too long!

I did do a bit of Ebay shopping for things like door cards and stuff, looks like they're a no go on selling so at the very best I'll have to sell the doors as complete and collection only.

MX5 plans

Here are the alterations required to the 'build a car on a budget', so an MX5 can be used as a donor. They were created by Saturn Sports Cars, who don't appear to exist anymore. They were then briefly hosted by Gillham, before they replaced them with another set. Unfortunately, the new set has only half the pages, and is still missing the measurements that this original had. 

The document does reference a Saturn Sports cars copyright, but as I have no means of contacting the author I have put them on here with the intention of removing them if requested.

I would strongly recommend you do not treat them as anything more than a guide, and use an amount of common sense when making the alterations. The rest of this blog will contain information on what I am planning to do, so feel free to use the ideas.

MX5 Plans

And more chassis...

Finished the triangulation now;

I've deliberately left all the rear suspension for now. I've ordered the diff cover from Talon Motorsport, and I'll build the diff cradle and suspension around it.

So the next stage will be the transmission tunnel. The only change will be to open the ends up slightly for the MX5 diff. I can then fit the front suspension brackets and start the wishbones, but I'm hoping that the cover will arrive before then.

I'm going to need to find a new welding helmet though, it didn't go dark during one of the welds last night so I think the auto darkening circuit is failing. Then again, it might just need the glass cleaning/replacing.

Suspension thoughts part 2

As mentioned, the suspension wishbones are going to be all new, mainly to preserve the longer wishbones at the back. So, armed with the Haynes manual, the Saturn modifications and some clever Google searching, I came up with this;

First stage, front wishbones. Looks like Saturn use the same mounting points for the wishbones top and bottom. The front upper and front lower jigs have length dimensions, and the width dimensions are dictated by the brackets and the upright fixings. So I'm happy I have everything I need there.

Rear wishbones. Now these are going to be fun! So as far as I can tell, the Saturn plans don't contain length dimensions for the wishbones, so they're no help. The Haynes plans do contain dimensions but for Sierra based uprights. So a bit of creative thinking is needed. The lower wishbones are quoted to be very similar to the Haynes wishbones,which are 381mm (centre to centre). The wishbones brackets on the chassis are 265.5mm from the centre line. That means the lower outer fixing for the upright is 646.5mm from the centre of the car. I think that is a good starting point, which means I need to make the new wishbone the same dimensions as the Haynes wishbone, but with the layout the same as the Saturn wishbone.

Here is a picture of a rear upright from a mark 1 MX5;

Unfortunately it's from a US site so everything is in inches. Converting to the metric system, the top measurement is 149.225 mm and the bottom is 114.3 mm. In basic terms, it means on the upright side, the top wishbone has got to end approximately 35 mm shorter than the bottom wishbone.

So, back to the Haynes manual. The bottom wishbone mounting point is 265.5 mm from the centre line. The upper wishbone mounting point is 301 mm. So on the chassis side, the top wishbone has got to be 35.5 mm shorter than the bottom wishbone.

This means that the top wishbone has to be overall 70.5mm shorter than the bottom wishbone. With the bottom one being 381mm, that means that the top one needs to be 310.5 mm long. That is 50mm longer than the original Haynes wishbone, but probably double the length of the Saturn wishbone.

Of course, there is the added complication of the rear driveshafts. I already know I need to alter the propshaft, I didn't want to have to adjust the rear driveshafts as well. Maybe I ought to wait for my donor...

The suspension brackets have now arrived, so I can at least get them fitted. Although I still have the whole rear suspension area to fit... and the diagonal bracing... and fully weld the chassis... and do the aussie mods... I'm glad I'm treating this as a fun hobby rather than a career!