JL Engineering A310 historic comp car.

So the old Wheeler Dealers car was sold on to start a new life as a historic rally car. Initially we just nut and bolted the whole car, replaced the rubber brake lines with stainless braided hoses, removed the rear brake limiting valve and installed an adjustable brake bias. All fluids were replaced matter of course and we run the car at a few test days here and there so the new owner could get some seat time.



The car was still in a reasonably standard form and the old tyres were becoming a limiting factor on the circuit. We decided that if we were to develop the car a safety cage, new wheels and tyres would be sensible. So the interior was stripped, custom cages fitted a safety cage, engine bars and floor protection. I fitted the Tillett seats, and made new lightweight door cards and of course the new Gotti rims with Kumho rubber.







As the new owner is also rather tall the steering wheel boss had to be extended to achieve a comfortable driving position with the new seats fixed in place. So I fired up the trusty lathe and made a new boss.





So once the work was complete the car went off to a few more test days at Castle Combe and Brands. Now we had really made some progress. The owner admitting with the new tyres the violence of the road holding was making him sick! He is quite an experienced driver/competitor and was blown away with the Alpines ability.



Unfortunately the increased cornering speeds soon showed up the inadequacies of the standard wet sump system on the old V6. Oil surge made short work of a couple of rod bearings so it was onwards and upwards. Onto the next stage of development..

So this is the plan:
Engine and gearbox out.
New aluminium rad.
Complete new water system to be fabricated in aluminium.
Gearbox rebuild.
Limited slip diff, not ATB.
2849cc Engine rebuild, high compression, cams, triple Webers etc.
Oil cooler and Accusump.
Rewire with safety cutout and plumbed in fire extinguisher.
New twin fuel pumps.
Lots of other little jobs.

The plumb in fire extinguisher, electronic battery cut-off, mud flaps, Brantz trip meter and other bits and bobs arrived along with a new larger core aluminium radiator.



After a bit of a search we found a pair of Weber 40it carburettors with the manifolds and stacks so they went into stock ready for the engine build. Although expensive these triple downdraughts are significantly more affordable than the sought after 40/46IDA 3C's.


Engine and box removed.


I started stripping down the car and had a quick look at the state of the rod bearings after the oil pressure loss, looked pretty much as I thought. Found lots of junk in the oil pickup strainer, bits of silicone and dirt so it was only a matter of time before this had happened. No biggie as we had another engine in the pipeline to replace this one.


After removing the water pipes I cleaned the transmission tunnel and rear cradle then painted and undersealed it all. The car was in excellent condition and has absolutely no rot which is pretty unusual. We then made new aluminium central water pipes to be run down the spine of the chassis.



The gearbox which we are keeping as a four speed was covered in grime and had been leaking for sometime. Someone had tried to bodge some silicone sealant around the joints to help with no luck.

We stripped the box down cleaned and inspected all the parts. All the syncros and bearings looked good so we replaced the diff bearings as a matter of course. We wanted to use a limited slip diff but wanted a true locking LSD rather than the Quaife ATB style diff. After a some trial and error, lots of measuring and double checking we had a Diff suitable for our application.

ATB on the right LSD on the left.

Who made the plate diff?

Hi Richard,

The diff was made at Dave Mac props/Gripper diffs. Friends who run a bunch of historic race cars have used their drive shafts and diffs in a Talbot Maserati, Coopers and an early Gordini. They seem to work ok. So hopefully it'll be a nice diff for all the Renault boxes, going to try one in a lairy GTA turbo next.

Cheers,

John.

Why didn't you use a muscle car carburettor

[BIG_MVS]

Who bodged the gearbox then?



Not you know who surely?

Not sure who attacked to gearbox with silicone sealant to be honest, may have been there sometime. Even if wheeler dealers were the culprits Edd doesn't do any of the work so his reputation can live on untarnished.

So next on the agenda is getting stuck into the engine build. We have decided to go with the 2.9 oddfire from the atmo GTA to keep things simple and also benefit from the changes that had been made from the A310's original 2.7. This particular engine came from Tony Smiths Alpine horde and had been sitting sometime but was a good starting point.

I started by stripping the engine and discarding any of the worn or damaged components. Starting with the block it was cleaned then inspected. All was well so the block was sent for vapour blasting along with the cam chain cover, sump, original A310 sandwich plate, rocker covers and other small parts. What is most important is the masking process before the vapour blasting. If any part of the oil system, internals of the block, inside rocker covers, oil galleries etc get blasted with media then there is a very high risk your engine will suffer later down the line. Masking up takes a long time and adds to the cost but is imperative to building a long lasting engine.

The only way to ensure you start with a clean block is by removing all the oil gallery plugs and cleaning the galleries out with a gallery brush, there is always nasty bits and pieces lurking around in here.




All threads are chased to ensure the correct torque is achieved and everything cleaned with lots of solvent.


A set of liners were assembled from handful of sets to find the best starting point. These were then paired off with a great set of standard pistons I found and torque honed to achieve an accurate piston to wall clearance. The crank measured up great and just needed a polish.

Pistons were weighed to within a 0.1g and the rods matched end to end. The whole reciprocating mass was balanced and the flywheel, clutch and pulley all balanced separately. The flywheel was lightened a few pounds too. We decided to use the uprated helix clutch that is available off the shelf for the A310 and should more than good enough.




Managed to get hold of a nice set of new old stock rod bearings from Mr Sage as I only had evenfire rod bearings in stock.


Made an adaptor for an oil pressure gauge which will come in handy later.

Looking good Johnny boy. Whos lairy GTA and whats lairy about it?

John, what car did that oil pressure sender come from?

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Nice work John, be good to see how this unfolds. Gives me good motivation to get the Tatmo engine done, further be good to see them side by side on a dyno to compare the approaches and performance of the odd and even fire units in similar form. l think this would be really interesting for folk, and as a forum & club likely the only ones to do it. See you have lightened the rods (big end machining detail) did similar on some Fiat rods back in the day when I used OE, managed to shave off 39g each safely, only to have someone comment that for all the work and hours I had only saved "a packet of crisps", at which point I nearly poked their eyes out!
What valve sizes have you gone to on this?

Cheers,
Martin

We should do a comparison of fuel injection v Holley v standard set up with my DD car, Steves white Atmo and Simon Gamblins Atmo. All have similar exhaust set up so would be a good comparison. I think one of the french Alpine mags would love that story.

Tony, next diff should be going in a Scandinavian GTA with a supercharged PRV.

Mark, the sender is from VDO, I initially used it in my VW. Its a 1/8 npt thread like a lot of the aftermarket senders.

Martin, the rods have had big ends and little ends matched to within a decimal point but no lightening. Durability is high on the list with this build as its destined for stage rallies and failures write you off instantly so wont be experimenting too much. I chose to keep standard valve sizes as the carburettors are 40mm throats but used stainless steel, waisted stems that have a few advantages. I would love to get the cars to the same rolling road to get some comparisons, I will let you know what we get- should be going this week.

Here's our lightened and balanced flywheel with the 300nm clutch plate and new flywheel bolts. As the crank was polished and then chemically cleaned its best to change the input shaft bearing although it felt ok.



The inherent oil surge issues that have been a problem with the earlier design of the PRV doesn't seem as bad with the Z6W engines and later. But to cover all bases I baffled the sump and have also installed an Accusump in the oil system. This Tee's in with a one way valve after the Setrab oil cooler and if oil pressure drops below 1 bar then it injects its oil capacity into the galleries to prevent any damage. The best part in my opinion is that before you start the engine you can arm the Accusump which means on start up you will already have full oil pressure at the bearings. Such an excellent feature to protect your investment.




While I was waiting for some of the machining to be done I made a new aluminium centre console. This was to mount a reverse lockout because they don't come with one- finding reverse when you least want to can be a problem! I didn't want to use the standard centre console as it is quite flimsy so started from scratch. It was designed around the group 4 cars I had seen out and about. I have left it plain aluminium for now but will be flocked with other dash parts once its had some testing.

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Ok good stuff. Pity you have it already assembled, as I would have said drop by and we could have flow tested the heads, manifolds and carbs and been a bit more scientific about whether the chokes would be a / the restriction, as 44mm IDF with 36mm chokes will flow 103 CFM, 40mm IDF is about 9.5 CFM down on a 36mm choke. The OE 44mm inlet valve choke flows at about 93 CFM (9mm lift upwards), so likely there is power to be gained over OE valve sizes if you are on 40mm chokes / throats. What valve seat angle are you using, OE 30 degree? What rule / regulation restrictions have you got?

That would have been cool, is it a wet flow bench you have? The car had to be ready for events this summer so as much as I would have personally loved to spend more time on playing with the engine I had to just get on and do it. It will be coming back for a refresh end of the year so there will be plenty of time to develop it further. I have another set of heads with different cams to and lots of other bits and pieces that I want to try. Seat angles are 35, 55, 70. The car is MSA compliant, we've kept the distributor on point and had to look at the homologation papers for brakes and bits but it shouldn't be too strict unless it starts winning.

Some pics of the heads



And my favourite cam supplier ground me these based around a cam for another 2 valve per cylinder engine that I love. My aim was to design it to work well as a package with the headwork, induction and exhaust we are running. With our cam duration, rod length and static compression ratio of 10.6:1 this gives us a dynamic compression ration of 8.3:1 which was what I was after. I guess the proof will be in the pudding..


Dry built it a few times to measure everything twice.


It would have been rude not to perch the carbs on top for a photo.