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The buggy is nearly finished :D


Rippthrough's picture
Cunning Stunt Licker
Posts: 221
The buggy is nearly finished :D
#1 Submitted: Wed, 14/10/2015 - 17:24

Given the pics in the avi and the earlier topic on what people drive ( some of you know about our little toy back from when it was racing, thought I'd do a bit of a project thread on here as it's almost ready to race again.

Anyway, since then it got took off it's wheels, onto axles stands, and the old rotary engine ripped out, which left her looking rather sad:

Even more so when someone chopped all the tubing out of the centre of the car:

This was due to the newly rebuilt rotary engine blowing up, running out of money and it taking over 12 months for the guy who rebuilt it to get it sorted, so she got left in the shed for 12 months. There were some very strange 5ft high transparent plants growing in the dark when we opened the door mind. I'm not sure what they were but I bet smoking them wasn't legal! Must be all the soaked in oil. Maybe it was the start of the triffid invasion.

Rippthrough's picture
Cunning Stunt Licker
Posts: 221
Submitted: Wed, 14/10/2015 - 17:50

As the new engine is longer than the rotary, we chopped out the centre of the beam tube so that we can push the transaxle forwards into the cabin a couple of inches to keep the rear overhang similar, we don't need that reinforced part there any more anyway because it was what the old torsion bars used to run through/work against, so it was basically a great hunk of steel tube and plate doing nothing (as the springing is now done by the 4 mahoosive coil springs)
Free weight saving! :D

Anyway, one immediate issue was the new engine used a pull clutch, and there's no room in the transaxle to make that work, so we needed to convert to a push clutch somehow. We found a plate that was a similar size and a diaphragm that would fit, but the spline for the Renault transaxle was wrong, so we nipped up to CG Motorsports to see if they could stick us a Renault spline in the clutch we'd found (or a paddle version of it).
We used to just weld centres in off-the-shelf paddles for the VW clutch setup, but the splines never last that long as they soften a little from the welding heat no matter what you do to keep them cool, so we wanted to do it 'properly' this time.

Anyway, Mick had a good look, and decided he'd got an even bigger paddle and push diagphram already sat on a shelf that would go on the standard flywheel - provided we gave it a skim to take the raised surface off it - so we came back with a nice 230mm setup:

Which looks a little more promising than our old lash-up of Renault/VW/RX-8:

Rippthrough's picture
Cunning Stunt Licker
Posts: 221
Submitted: Wed, 14/10/2015 - 17:55

Due to a bit more weight/leverage and stress being anticipated this time, we went with poly mounts for the transaxle instead of the old solid strap system, there's no real movement in them for the engine torque, etc, they're simply to reduce shock loads on the gearbox from landings/frame flex.
And as you can see, moving the transaxle forward proved to be quite a tight fit....

Then we mocked up an adaptor plate for the bellhousing to the new engine, and bolted it up just to see how it fitted:

Which, as it turns out, is almost exactly where the rotary was after the alterations.

That big chunk of steel holding all these tubes together in the middle wasn't important, was it? I'm sure it wasn't. It'll be fine. Maybe.

One advantage of the rotary was the flat sump needed very little in the way of oil control, not the case with this, so we'll need to do some work on the sump later on.
Anyway, whilst we were at it, we thought about maybe going a touch wider on the rear tyres to compensate for the additional rear weight bias, might need a rethink on that one, not a whole lot of room left...(Hah, watch this space!)

And we checked the new clutch, after chopping a hole in the middle of the adaptor with the angle grinder, everything fits okay, but we've got loads of spare room in the bellhousing - there's a good 30mm of wasted space there, maybe more with a tweak of the release bearing, which makes the clutch quite snatchy as the lever arm is at an angle, so we might have a little rethink there, we stuck 2 release bearings back to back for the minute just to test the pedal feel:

And, after a bit of a trawl around scrapyards and ebay, we accidentally might have bought this, an Eaton M112 supercharger from a Jaguar 4.2L was so cheap it seemed rude not to...

Anyway, that seemed to fit so nicely just by the inlet manifold it seemed a shame not to use it:

Rippthrough's picture
Cunning Stunt Licker
Posts: 221
Submitted: Wed, 14/10/2015 - 18:38

However, the more we looked at the space in the bellhousing, the more we we bit the bullet, chopped the new front mount for the gearbox back out, took the angle grinder to the bellhousing, and started moving things again...

Bellhousing, meet angle grinder, angle grinder, meet bellhousing.
And bring your friend TIG welder...

Redid the engine and gearbox mounts, which required even more frame surgery:

And as a comparison to where the old engine was, this is the old engine cage:

Anyway, we'd had enough of chopping out old bits of the car, so decided to make more shiny new bits, and everyone loves a shiny exhaust, no?

It took quite a while to get the lengths and routing all right, there's about 2 weeks of evening work in this, even though most of it was sorted by the first two nights, tweaking and altering after that/finishing it off took a while!

As the gears are fairly wide in the transaxle (It's out of a Renault van, so not exactly sporting...) the lengths are set to bolster the bottom end and midrange torque rather than outright peak power.

That should be enough shiny exhaust pictures to keep anyone satisfied :D

Rippthrough's picture
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Posts: 221
Submitted: Wed, 14/10/2015 - 18:42

Okay, one BIG disadvantage over the rotary engine, is the sump being so deep - reducing ground clearance - and needing a lot of oil control/baffles due to the constant jumping around, as mentioned a few posts back.
It being pretty vital to the engine reliability, we bit the bullet and spent some pennies on a dry sump pump rather than relying on sets of baffling, and we set about converting it, few issues along the way but we got there:

Yes, the belt is too long, we know. And yes, that is a bright pink mug of tea in the background.
This gave us a good 3+ inches more rear ground clearance, so hopefully the rear of the car won't take quite such a battering on steep/stepped drops like it did at Kirton.

And a shiny chunk of ally billet converted itself into a pulley. Magic, eh?

Onwards....after fitting the supercharger on some temporary brackets, and tack welding the silencer up for it's final position, it quickly became obvious that our oversized 165 amp alternator wasn't going to fit in the stock location.
In fact, it wasn't going to fit anywhere we could get the belt drive on it, short of putting a gear on it and running it off the flywheel teeth...which resulted in a slightly poor solution of driving the alternator on a seperate belt that's also driven from the supercharger pulley, this might result in too much belt slip/wear, but it was the easiest way around it.
Well, the easiest way around it would be to fit one of the new starter/alternator all-in-one units, but the aftermarket versions of those at the minute bring a tear to the eye and a squeak to the voice when the invoice appears, so that was a no-go.
Try it and see method ;D

Did a couple of beer-mat sketches after mounting everything of the old bodywork vs roughly where the new will need to sit, old:

New, sorta:



One problem with moving the engine and gearbox so far forward, is it didn't leave much room around the radiator/fan setup, so we ended up chopping those brackets off and moving the radiator up and forwards, not ideal, but cooling takes priority over CoG here:

You can also see how much ground clearance/departure angle we've gained with the new sump setup, as that's the old engine cage, which used to have the topmost bar horizontal.

Rippthrough's picture
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Posts: 221
Submitted: Wed, 14/10/2015 - 19:35

Okay, another update before you all get bored of seeing it :D

Bit more of the plumbing and mountings were finished, yes, I know, the outlet on the charger and the inlet to the plenum aren't great, but it's a case of make something quickly that will work well enough for those pieces, as they can be easily upgraded later on when we have more time spare:

You can also see the fun we're having with the alternator...

was starting to look a bit tight in there even with the old cage on, so we cracked on with making a new one (again, out of T45 tube - you never know if someone is going to give you a love tap up the's like real life Carma!)
As the dry sump has lots of clearance in the middle between the fittings, we went a little more substantial with the under-engine guards this time, as we were forever beating the old ally sump plates back straight after events, it's only thin-wall tube so it weighs very little and gives a lot more stiffness behind the sump guards:

Oh yes, we mocked up the silencer there too, just about fits :D

And the new engine cage from the side:

It shows pretty well how much extra clearance we've gained from moving the transaxle/engine/shortening the bellhousing and tilting the transmission slightly (now there's no torsion housing tube in the way).
Unfortunate side effect is the centre of gravity is going to be higher at the rear of course, but needs must.

Cynatix's picture
Fluffy Bunny
Posts: 48
Submitted: Wed, 14/10/2015 - 20:25

that would be SO badass to drive around in, Real life and Carmageddon.

Max says: "Screw seat belts!"

Rippthrough's picture
Cunning Stunt Licker
Posts: 221
Submitted: Wed, 14/10/2015 - 20:44

Yeah it's a lot of fun, if we go on a trackday we end up with a queue for passenger rides, I ought to sell tickets, some of it in action with the old engine:


I may be a bit of a photo whore. Slightly.

Edited by: Rippthrough on Wed, 14/10/2015 - 20:46

AlexTSK's picture
I was in the War!
Posts: 2844
Submitted: Wed, 14/10/2015 - 21:16

Hah the little buggy looks like quite a blast! Nice progress photos dude :)

Rippthrough's picture
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Posts: 221
Submitted: Wed, 14/10/2015 - 22:39

Only place big enough for the airbox, means a bit of reworking of the bulkhead though. For the moment it's going to draw from the main roof-fed airbox, but it'll probably get a seperate feed from the side scoops once we get chance:

Old dashboard got ripped out along with the wiring, to make room for some additional instruments and a new dash:

And on with the weird shaped dry sump tank (only place we could find for it is behind the pulleys in the rear engine cage - believe me, we looked elsewhere - hence the strange shape:

Okay, whilst the driveshaft angles were still just within limits (moving the 'box forwards didn't help them), with the extra power/stress anticipated we had a bit of a question mark over the longevity of the CV joints, they get pretty hot from the transmission loss as it is.

And, after a few weeks thinking about it, we bit the bullet and decided to go with longer driveshafts to reduce the angles. Of course, that means moving the outer CV joint outwards to suit, and the car is already as wide as we can practically go at the rear that becomes a bit more difficult, so, cue shiny bits:

Whacking great spindle/hub that's large enough to pass the CV joint right through, with ally upright to bolt to the rear trailing arms, of course, that means we can't drive the discs off the rear of the spindle any more (The bearing preload nut is there now) hence the ally brake bell instead of bolting them to the rear of the hubs as presently.
The CV then bolts up to a machined drive ring that is clamped down on by the wheel:

Bit of inlet manifold modification with a set of old injectors off the RX-8...

Fuel shortage? What fuel shortage? :D

You know how I said the dry sump tank had to go in a really bad place because there was nowhere else for it?
Well, here's praying we don't get too much of a carma-style love-tap up the arse...

And the worst part of all builds, just when you think you're nearly done, stripdown time!

To clean up and weld/make all the supporting bits properly. Then back together.

Mocked up new rear suspension.
I reckon that ought to cope with some bumps, eh?

And the gofasterjuice can get to where it's needed now:

Fairies have been in, apparently they do panelwork, who knew?

As you could guess from the header tank locations, space is getting kinda tight now, and there's still some more plumbing and fibreglass/ally heatshielding to go in yet, you don't even want to see it with the dampers and some panels on.....

To be continued....later, when I've slept.

Rippthrough's picture
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Posts: 221
Submitted: Thu, 15/10/2015 - 12:43

Bit of framework to make it easier to shape the rear bonnet/scoops, yeah, you know how I said the engine bay was quite tightly packed? :D

Then it was the start of spaghetti junction time:

Then on with having the rear hubs anodised and getting things assembled:

So that we could start tacking up some new rear arms:

And new rear discs, same weight as the old ones but 320mm diameter instead of 300mm:

After trying the double diaphragm clutch the other month, and almost getting a hernia, went hunting for a tiny pull-type hydraulic slave cylinder, eventually found one that would fit, so onto the other end:

Yes, strange shaped bulkhead with the fuel tank behind plus a requirement for the fluid reservoir to be behind the bulkhead led to a strangely shaped pedal too. Only a mock up, a proper pedal will be made later (the ally tube is too soft to support the bearings long term, probably make a sleeved one), but seems to work ok.

And everything fell off the car again so the rear geo. jig could go on to finalise the rear arms: