Recommended Rev limit for 2.7L 6 cyl, I'm curious Options

[nine14cats]

Anyone know what the factory valve train is good for at the upper rev limit in terms of reliability? I've got a pumped 2.7L in my 914 with carbs and 10.5:1 compression, mod heads, big cam...the works. Last year I ran without a rev limiter (i'm a knucklehead) and used 7500 rpm as my limit. Towards the end of the year I over-reved the car with my right foot to ~8K a few times and broke a few rings. I had the engine dis-assembled and it's all prettied up again (including more mods!), but I was curous as to what the motor's hardware was originally designed to do. I've heard alot of folks recommend 7200 rpm as safe and reliable.

I purchased a new MSD ignition with the adjustable modules. I can program the rev limit in 200 rpm increments. I'll start at 7K for awhile.

Anyone know what the design limit is? The car has stock valves, springs, crank. Heads have been chamfered for clearance and the pistons are JE. Camshaft from webcam. Weber triple throats on each side. The motor will rev easily to 8K with the tap of the foot.

Thanks in advance for the opinions! (IMG:style_emoticons/default/wavey.gif)

Bill P.

[Brad Roberts]

I cant really say whether you are good to go or not. It depends on what tolerances your machine shop used on the crank/case/rods/pistons. Most race engines tend to be a little on the loose side. If they built it with stock tolerances... then you will need to go easy on it for a few hours.

We break engines in at the track in normally 2 sessions on a Friday and race on Saturday and Sunday.

I would certainly use a open track day to break it in after the dyno session.


B