12 replies to this topic

[Cooper-202S]

Does anyone know where i can find some details on the 850 race engines that were used in the early mini sevens.

I've had a dig arround but can't find any details.

Is there any information on the web or is it all to long ago?

[icklemini]

Spoke with the mini7 club?

[Bungle]

theres a section in the back of Visards bible

[Cooper-202S]

Spoke with the mini7 club?

Sent them an email this afternoon.

[Cooper-202S]

theres a section in the back of Visards bible

Just re read it, some of it still doesn't make sense, the cam durations quoted are huge for a small bore engine?

What I had in mind was a 850 with flat top +0.040" pistons reworked crank and rods with a 12g295 head that i have that has been heavily skimmed.
Just not sure what type of cam to go for with twin 1.1/4" carbs and an lcb.

[Sherlock]

The late Clive Trickey recommended a 544 camshaft for racing use or a 948 (the old 997 Cooper cam) for road. These are both the Leyland ST profiles but I suppose they have an equivalent from Kent cams or similar. The old ST profiles are still available from Mini-Sport.
544 Cam timing:
Inlet opens 34 deg Before top dead centre
Inlet closes 74 deg After bottom dead centre
Exhaust opens 63 deg Before bottom dead centre
Exhaust closes 39 deg after top dead centre.

Edited by Sherlock, 06 December 2009 - 09:45 PM.

[BLUE ITALIAN JOB]

have a look thru the aronline site under tuned minis , they give some details of the first of the 850 tuning - but do hope you have disc brakes ..

[Wil_h]

The cams did have huge durations, because they were for race purposes only with no consideration for low rpm drivability. also, these engines revved, so big cam needed.

The big problem with the 850 block is the lack of a centre bearing for the cam and the lack of suitable pistons readily available.

Edited by Wil_h, 07 December 2009 - 10:19 AM.

[downhillfast]

940 heads, pocketed block, cam bearings, centre main strap, 648 cam (special tuning) sprite or austin a 40 devon pistons, very high comp ratio. no power below 4k reved to 7.5k /8k on single choke carb. reece fish or split single weber 45. un silenced (yes I am that old) Would be no good in a road car but were huge fun on track. good luck )

[Cooperman]

Do they still race 850's? A race-tuned 850 really would be undriveable on the road. It's hard to do a really modified 850 these days as there are few places that can line-bore for the cam bearings for a sensible price, bearing-in-mind that the 850 used to just run the cam in the cast-iron block with no bearings and that won't allow the ultra-high revs needed. Also, the special 850 race forged crank is no longer available and the standard one will probably snap at around 6500 rpm.
A 998 is a much better bet as it just so much stronger.

[Joe555]

Yes great fun on the track, (I am that old too) have attached a couple of photo's from 1975 pehaps you are in them.

Joe

[downhillfast]

Great pictures Joe, Paddock hill before there was any gravel trap or run off! Just missed me though, I started in 77. The carnage looks very familiar, happened several times a season.

[mk1leg]

Hi..I Tuned my first mini a 1966 mk1 848cc back in 1978 and I max bored to same as cooper 'S' new rods, omegs pistons, crank Ni-tempered, 731 cam, stage 3 head, 3into1 manifold, 2" exhaust, 40dcoe webber, Duplex chain,sc/cr box............went like S**T off a shovel.....................