MG Sports Cars

FORGED 3,5 ROVER PISTONS URGENTLY NEEDED


Our KC SCCA, RV8 GT 2 racer is in sore need of forged pistons at this point in the project.

Stock Rover pistons will self destruct at RPM over 6,000 for a sustained period - for instance, a 16 to 25 lap SCCA Regional or National race.

The SCCA class rules require the 3.5 size Rover engine. My machinist tells me to try to go no further than +20 over pistons, + 30 at most.

The 3.5 engine is ready for the machine work phase - cylinder boring, cam bearing boring, cylinder head surface finishing, etc.

All is now on hold with the 3.5 Rover block until I locate forged pistons for the 3.5 liners. I can find nothing, short of custom made pistons from JE or Ross or TRW or ....whatever. Prices quoted for custom forged pistons are nearly $1,000.00.

I have tried the "obsolete" parts suppliers - EGGE, JC Whitney and several others - going so far as even pistons for the 1962 Buick Skylark 215 ci engines.

Will forged 215 Buick or Olds pistons work ? I don't see why not. Do you. But none are available.

I have searched the UK eBay sites and find 3.5 TVR, Morgan etc pistons - but no forged pistons. RPI Engineering may be a source but are nearly unapproachable with their web site requirements.

Does anyone in our group have an idea where to find good - maybe used - forged 3.5 Rover pistons ?

Phillip,

Prices in the UK for forged pistons or any other engine parts are double what you would pay in the US. What most of the racers in the UK do to stay within the 3.5 limit is to use the 94mm bore with a short stroke 63mm. crank from JE which is not a cheap solution and you still have to buy pistons, but there is more choice in the larger bore size.

I'm using Keith black Hypereutectic Chevy 305 pistons in a 4.35 engine I'm building at the moment, their OK for race use and very cheap but you have to use Chevy rods, piston size standard is 3.736"/94.89mm. and they are available in various compression heights. Search KB/Silvolite

A $1000 for a set of forged pistons over here would be considered very cheap! they normally cost £800+/$1600. RPI will not be much help as they are not really racing orientated and their prices are definitely not cheap.

You may be able to get some more information from a good technical BBS for the rover V8 I frequent, it can be a bit slow so be patient but you will get fast responses from the regular and knowledgeable guys.

[www.v-8.org.uk]

Good luck,

Kevin.

Phillip,

Heres an example of a forged 94mm.piston from one of my suppliers.

[www.v8tuner.co.uk]

Kevin

Kevin,

castlesid,

Thank you very much for this great information on forged pistons.


Phillip G

Phil,
Might be worth a call to Dan LaGrou at D&D.
[www.aluminumv8.com]
I know Dan has developed combinations of Chevy/Ford/BOP pistons, con-rods and head chamber volumes to arrive at some pretty high compression ratios for performance. Perhaps he can recommend a combination that includes a domestic made forged piston.

Decent , affordable pistons is the problem with my 3.9L project.

The Keith Black hypereutectic pistons that Kevin mentions are stronger than stock cast pistons, but they are still not as strong as forged pistons.

What RPM redline are you shooting for, Philip? Above 6 grand there are other components that may not live long either.

Graham,

Thank you very much for this advice.

I bought a bell housing from him, recently, and didn't think of asking him for American made forged equivalents for Rover cast, standard pistons. I hope there is such a thing. They would be so much less expensive.

But flat-top, 88.9 mm bore size (3.5 inches) is a small American size piston - I don't know. Hope so !

If anyone would know, it would be Mark Lagrou.

Phillip G

Carl,

The SCCA club races are hour long afairs on road race tracks nearly 2 miles around with Regional races of 16 laps and National races of 25 laps.

Overheating is the biggest problem - summer reacing most of the time - and everything is done to keep the engine and the driver cool. I, personally, use a "cool suit" and it really helps. The engine requires a huge water and oil radiator and at leat 8 quarts of oil with the Accusump. Lots of effort is put into cooling - and still engines blow consistently. Ducting is very helpful and engines are rebuilt over and over again.

I hope for 7,000 to 8,000 RPM on the engine I'm building now - for the GM T5 transmission has overdrive on 5th gear for the long straight aways and eventually I hope for a (3.09 locked) differential gear. I have only a 3.90 now (plus a 4.35, a 4.55 and a 4.87) that I use in my F Production MGB GT SCCA car. The locked 3.90 MG differential gear I will use at first will really not be good for holding down the RPM. The 3.09 MG differential gear is as rare as hen's teeth. I think it only came in the few Sebring and Le Mans factory cars. Let me know if you ever run into an MG B 3.09 final drive gear set.

Phillip G