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Valve ? Noise
Hi Helpers..
I have a noise that appears to be coming from my left bank of cylinders. I know it's tricky to diagnose these things over email, but here goes: It sounds like it's coming from a single rocker, and makes a kind of 'thack- thack-thack' sound, seemingly like a noisy mal adjusted tappet. The problem is I've set and reset them three times now and the noise is still there. Yesterday I tried again to no avail, but I looked at everything as best I could to see if anthing was wrong. It all seems ok. I checked the rocker shaft torques..ok. I examined the cam..ok. The feet on the ends of the adjusters all swiveled when the adjusters were backed off. Are they supposed to do this? It looks like they are. I've had the stethescope on the cam covers when the motor is running with no obvious bad noises coming thru. Each rocker is similar but distinct. Likewise with the chain housing- just a whirring noise. The 'thacking' is easiest to hear standing slightly away from the car. Before anyone shouts something nasty re. the pistons or heads/studs etc, compression is fine and there are no signs as far as I can tell of cylinder leakage. I tried to wiggle each valve and look at each spring but it seemed really tricky. Is there a way to do this? The noise is obvious to me, but isn't too bad. Maybe it's just an old Porsche noise. 92000 miles so far. Probobly time for a top end job? thanks! ------------------ '72 911 TE |
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06-25-2000, 05:50 PM
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The 'swivel-foot' is definitely supposed to pivot, but the problem is most likely too much wear ... people tell me they can wear out and start making extra noise, but I have never heard it, personally! Logic tells me it would only be the intake rocker swivel-feet that would be likely to wear out, since the exhaust set are under oil overnight, and immersed in oil upon startup, so you may want to buy three replacement adjusting screws and try replacing them one at a time until all of the noise goes away, or is diminished significantly. Or, you may just want to do all three intakes on that side at once! The adjusters are not terribly expensive, about $6 each, if memory serves me right.
------------------ Warren Hall 1973 911S Targa [This message has been edited by Early_S_Man (edited 06-25-2000).] |
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06-25-2000, 06:29 PM
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