'87 Sports Libre BMW 2cv & 94 MX5 Hillclimbers - MEGA UPDATE

Well... I was going to upload pictures of the new cylinder heads.. but have one of Sharky II. One of 3 cats in SSSB.

10671288_10203560070656786_6589655291155981773_n by Alex de Vries, on Flickr

Ahh no, that was heading out to sea at a beach further north, Watergate Bay, on an 8-9ft unbroken steep wave. The nosecone will be vertical when landing the other side, the weight of the crew at the front will (hopefully) pendulum you back level unless you've been particularly savage attacking the wave and there is an onshore breeze. Similar situation though. Do you want to crew some time?

Right.. now back to automobiles... here are a couple of pictures of the heads that will be fitted to green car v3.0. You can't tell from this but both the inlet and exhaust ports have been modified considerably by the best in the business (BMW used him), there are also lighter buckets and some trick cams inside.

DSCN2001 by Alex de Vries, on Flickr

The throttle body mount is now port matched and also gives the throttle body a direct shot at exactly where the good stuff needs to be for maximum performance - (may or may not work with 2cv box and new intake manifold design.. tbc)

DSCN2002 by Alex de Vries, on Flickr

Del West titanium valves and retainers, 2mm larger on the inlet, complete with beryllium valve seats. These heads were run up to 11,000rpm with no float when testing in California.

DSCN2003 by Alex de Vries, on Flickr

Ready for some more?

Green car is up on his stands at the Super Secret Shore Base (SSSB), previously known as RSPCU (Royal Society for Prevention of Cruelty to UMMs), I have some time back from sea and there is a metric duck ton of parts boxes stacked around the place..

LETS GO!


IMG_0998 by Alex de Vries, on Flickr

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Oooo some shiny parts... please admire...

IMG_0994 by Alex de Vries, on Flickr

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First thing to sort out is the front engine cradle has to be remade to work around the new exhaust headers and to work around and also mount the supercharger, intercooler and a small oil cooler for the Rotrex itself.  This is made from 20mm box section that has a 2mm wall thickness.

IMG_1033 by Alex de Vries, on Flickr

IMG_1034 by Alex de Vries, on Flickr

The easier side completed, lets have a look at the starboard side which has the charger to mount...

IMG_1037 by Alex de Vries, on Flickr

I must've been quite tired and happy at this point..

IMG_1038 by Alex de Vries, on Flickr

And a brace between the two sides that can also be used to secure the bracket that holds the small oil cooler and acts as the lower intercooler mount.

IMG_1044 by Alex de Vries, on Flickr

Very handily my friend Dan of Buffalo Builds is just the other side of town so I knocked up some CAD templates (Cardboard Aided Design) and popped over for some dimple die magic... et voila!  Because these are speed holes right?

IMG_1140 by Alex de Vries, on Flickr

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IMG_1146 by Alex de Vries, on Flickr

With the charger, and pulleys mounted up...

IMG_1145 by Alex de Vries, on Flickr

And how it all fits with the intercooler up there too.

IMG_1002 by Alex de Vries, on Flickr

So.  You saw one of the three Setrab oil cooler boxes earlier... because the intercooler is in the position that I originally had the main oil cooler there had to be some shuffling around, and the wings seemed the only likely place to be able to position more.  More is also much better as he's going to generate considerably more heat the more power he makes!

I'm slightly worried about clipping things when hillclimbing and I don't want to smash oil coolers off that easily and wreck the track so these mounts will have to be pretty bombproof.  Mounted to the main chassis rails there should be enough room at the front of each wheel well to fit a cooler with a small SPAL fan on the rear in suck through configuration so that even when sat in traffic there is a little cooling airflow.  They have to mount far enough out into the wings to clear the cylinder heads and also be tall enough so that the mounts for them don't contact the top of the head, in addition they also have to lean back slightly to fit inside the wing profile.  There could probably be a more elegant lighter way to make it but that steel profile was what I had lying around in quite considerable lengths so chopped some up and welded it all together making sure to box the ends and bases in.

IMG_1106 by Alex de Vries, on Flickr

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You wouldn't believe how long it actually took for me to think these out and make them... silly!  Finally mocked up with an oil cooler and SPAL fan, plenty of room in the wheel well.  Then etch primed and painted in some Simoniz Chassis Black.

IMG_1088 by Alex de Vries, on Flickr

IMG_1089 by Alex de Vries, on Flickr

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More power needs more grip, I was running 175/55r15 Yokohama Blu Earths beforehand which were good and i have no complaints, but they weren't anything particularly special and I did have the back step out on a couple of occasions (remember there is also jack all weight back there apart from fuel).  Toyo make the R888R in a 195/55r15 which I thought may just fit with some bodywork adjustments to the rear wings.  Well.  I was quite wrong.  Fire up the mill!

IMG_1020 by Alex de Vries, on Flickr

IMG_1001 by Alex de Vries, on Flickr

Hmm.. these are clearing the inner wing now but poking out considerably.. spacers needed for the rear wings I feel!  What are your thoughts on how far a tyre sidewall will expand outwards when hot?

Can’t wait to see this on the move. I can’t help but be concerned about those tyres though... will you not have excessive flex in the sidewall? No harm in more wheel girth 👀

Now all of that degreaser has turned up it seems about the right time to whip the motor out and check the gearbox ehh…

IMG_1142 by Alex de Vries, on Flickr

Amazingly no weeping around the input shaft and the clutch still looked hardly used, which considering it was designed for 29bhp and had 110bhp regularly being dumped straight in at 4000rpm I am very surprised, great work Valeo! But I am almost certain that it won’t cope with anything over 120bhp so we have a flywheel that has had the clutch plate side machined open a little more for a larger clutch… which was quite boring so this is the only picture you get of it:

IMG_1143 by Alex de Vries, on Flickr

All back together again and now I feel like a monster. Poor derpy green car.

IMG_1049 by Alex de Vries, on Flickr

What have I done!?!

IMG_1047 by Alex de Vries, on Flickr

Just running the Rotrex on 3 ribs?

I have had this thought recently also.  The wheels are banded to 5.5 inches which is the minimum width recommended for a 195mm tyre that I've seen on various tyre sites.  I have sent an email to Toyo UKs motorsport department to ask their opinion.  

Ideally having them rebanded to 6.5 inches would be the best but there is not enough room with the current width of the front arches that this wouldn't look silly with wheel and tyre poking out.  The rears less of a problem as I can make the wing spacer larger, but I'd like a matched set.

I'll let you know what Toyo say.

Seeing as we’re on a bit of a roll with pipework check out this stainless Tig welded exhaust, a thing of beauty up close as well. Knocked up by a prototyping engineer in Bristol.

IMG_1175 by Alex de Vries, on Flickr

Additional bung Tig'd in for EGT probe in the port side header.

IMG_1176 by Alex de Vries, on Flickr

Also a bung for the Lambda sensor just after the Y join underneath the gearbox.

IMG_1177 by Alex de Vries, on Flickr

So now the cam debacle has been sorted why haven’t I buttoned the heads up? Well, can you see what is missing in this picture? Just zoom in on that right hand side lower inlet valve….

IMG_1286 by Alex de Vries, on Flickr

Yes. NO DUCKING LASH CAP.

IMG_1259 by Alex de Vries, on Flickr

DUCKBALLS.

This is not an off the shelf item. Lash caps are used on titanium valves so that the valve stem is not mushroomed by the rocker arm. They are made from a tool steel and have a specific hardening process. We use H11 tool steel and 56HRC. Also handily both valves have just slightly different diameters, and of course nothing that is off the shelf… we are looking at 4.9735mm. Doh. Christ knows where this has gone missing in transit.

To cheer me up here is more white stuff. Fresh from plasma coating at zircotec is the stainless Tig welded exhaust headers and Y section.

IMG_1297 by Alex de Vries, on Flickr

IMG_1298 by Alex de Vries, on Flickr

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Anyhow, back to inlet plenum works….

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Getting there eh.

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Only one end cap is fully Tig’d on as everything else is just tacked to check for fitment. There are quite a few bungs to weld in for Air Temp, Boost Pressure and another take off point that will be blanked as I’ll use vacuum at the throttle bodies for the MAP sensor and BOV control. The monster TIAL BOV will have its flange welded on the currently missing end cap.

IMG_1357 by Alex de Vries, on Flickr

IMG_1356 by Alex de Vries, on Flickr

IMG_1354 by Alex de Vries, on Flickr