AZ964

I bought my 92 C2 Cab with 64k in Sept. All has been good until this weekend when I began to hear what seems to be valve tap between 2400 and 4000 rpm. It only occurs during acceleration and when the engine is under the most load.

I intended to have the 60k service, which I believe includes a valve adjustment. Is this just a case of needing a valve adjustment or do I have something more serious to consider (i.e. a bent valve)?

Thanks,
Jim

Bill Wagner

If it's occurring under load, are you sure it isn't pinging/knocking? If it is, it could be anything from a busted distributor belt to a tuning issue, in addition to valve tap. My experience with valve tap is that if they're tapping, they tap at all RPMs, and are most noticeable at the lower RPMs.

Hope this helps,

Bill Wagner

AZ964

It sounds like loose valves. But, it happened virtually overnight. I would've expected a more gradual progression. But, having never owned a 911 before, I am not really certain.

Arjan B.

Bill is right, valve ticking is the best way to hear at low rpm's, I know what it sounds like, because I adjusted the valves the wrong way the firts time in my 100 000 miles service [see thread] Under load could it be a knocking in the cilinders. DON'T drive anymore untill you know what he cause is.
You could disconnect the power of the ignition coil for the left side of the ignition distributor, so that part will not spark anymore and damage the engine. There is a black/grey connector on each ignition coil in the left side of the engine bay, acorss the blower fan. follow the ignition cable wich goes to the left distributor cap and unplug on the coil which feeds that cap the power connector.

axl911

Check your distributor belt. Sounds like pings from a failed dist belt.

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anthony