Tight case and exhaust valve problem

I recently bought a 1975 CA Carerra, 2.7 that has gone thru an update for chains and studs. It was running pretty well but hot. I assumed it needed an oil cooler. That year didn't seem to have one.

While preforming a tune up, I could not manually turn the crank even thought the plugfs were out. I had to use the starter motor. One the motor was hot is ran and idled great. The tight motor made me wonder.

Then one morning I lost power. Compression in # 5 was zero. I figured I had a bent exhaust valve. Then I noticed that I could pretty easily push in the valve springs. So I wondered if it was bent or if the Springs were just too weak.

Any ideas??????

That sounds like a broken outer valve spring to me! It is pretty rare, but it does happen!

That 'tightness' you describe concerns me and sounds like the source of the overheating! It almost sounds like the pistons were replaced, but were actually too large, and too tight for the cylinders. Any clue who did the 'stud' and tensioner work? When you get the 'zero compression problem' sorted out, I would strongly suggest a compression and leakdown test. And, you may want to change to a premium synthetic oil like Castrol Syntec or Mobil 1 15W-50. I would also recommend you seriously consider updating to a front-fender external cooler to alleviate the overheating!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 02-25-2000).]

Any update on what you found, and has the problem been fixed? Broken valve springs can be changed with the engine in the car.

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Warren Hall
1973 911S Targa