IrocMan

Hi,
I can't find good lifters for my engine.
What I call 'good' is a set of affordable lifters able to work with the schrick camshaft up to 8500 rpm.
I'm thinking about buying a set of new 993 lifters; light, polish and nitrurate them.
Do you think this would make them reliable for relatively high RPMs ?

Or, do you know which solution I get find (racing parts from a tuner) ??

Thanks for any advise !

Steve Weiner-Rennsport Systems

Hi:

You did not say whether this is a street engine or a race engine and thats a key part of your answer.

I don't know which Schrick cams you have but the stock lifters for a hydraulic cam are the ONLY ones you will find and no hydraulic-profiled cam runs past 7500 RPM. If your cams require mechanical rockers (964), then once again the factory parts are the ticket. RSR rockers are x-rayed before use.

With all due respect, turning any 993 engine even close to 8000 (much less 8500) requires a different crank, rods, oil pump, valves, valve springs, retainers, and many many internal changes & modifications.

I would be happy to supply some of these things, if you e-mail me directly.

IrocMan

Hi Steve,

The engine is a 964 engine for a club track car. Only heads are 993 parts I tune.
I was looking at 993 rockers because I know by experience that 964 rockers aren't reliable over 7700 rpm (7300 if not tuned).
The crank has been micro controled and x-rayed, and will be balanced, polished and nitrurated.
The Schrick kit requires mechanical rockers. The valve springs and retainers are coming from the same kit. The timing is near GE80 timing with better acceleration (as I think only schrick does for grand public applications).
Pistons and cylinders are new racing items (JE/Mahle).
Except the oil pump which I didn't check yet, everything is changed. Most of them come from Motorsport. Even the crank case is reinforced.
I had the chance to have all this for a good price, even the rods, and don't want to spent $6000 for the rockers !
I have a friend at Porsche who can have a set of 6 racing rockers, but 1) for a very high price, and 2) only 6 parts with 3) probably no issue to find spare parts !
So i'm looking for a way to have 12 hi rpm rockers. Even if we have to build them.
If a specialist tells me it's too hard (and expensive) to reach 8550, It will be nice @ 8000 !
I already made 7500 rpm engines (see my projects) which are reliable and still work perfectly, but 8000 rpm is for me a challenge for my last NA engine (next car is a turbo).

This is what happens with 911 rockers (this is a stock rocker from my 964) :


I send you a mail with more information, and suggestion.

kind regards