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Grady Clay Grady Clay is offline
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Join Date: Dec 2003
Location: Arapahoe County, Colorado, USA
Posts: 9,032
Asphaltgambler,

I agree with everything you posted. How much more radical are your cams than RSR Sprint Cams?

Porsche didn’t use stiffer valve springs for the racing 911 engines.
I approached the problem (as Porsche did) by using lighter weight components; Carrera 6 non-adjustable forged rocker arms with lash caps on the valve stem, Factory Titanium retainers, and more. This allowed the valve train to run 8500 RPM and more without ever a malfunction still using stock springs and settings. Yes, if it went to 9000 accidentally, I could see a shadow of the valve on the piston. If there was contact it was slight and full circle, never a bent valve.

Standard street 911 valve train will handle 7300 just fine every shift, occasionally 8000 and possibly some more. When someone “buzzes” their engine by putting it in the wrong gear that may be 9,000 or a lot more. With low compression pistons, they are sure to bend valves or worse.

I think the best investment is in proper stock or improved shift linkage to prevent any problem in the first place. Perhaps lots of track time and DE events. In almost 40 years, I have never put a Porsche in the wrong gear.

The race valve train is expensive but worth every penny if you intend to run much above 7500.

Best,
Grady
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Old 01-23-2005, 02:10 PM
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