Engine noise

My Car makes a funny noise after I accellerate past 4000 and approach 5000RPM. It doesn't do it when I accellerate gently, rather only when I really trounce on the pedal. It has made this noise since I have owned the car but I have payed little attention to it because I Rarely push it hard to 5000RPM. This recent post about pulled/broken head studs has me a little concerned since it does make a noise similar to a brap, brap, brap of exaust. The engine just changes from a steadly increasing whine to a deaper note. Should I be worried since the car does have 216,000 miles on it? How can I check for this? Just remove the valve covers and check that the studs are tight?


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Leland Pate

___79 SC Targa

I don't really have much of a clue what the sound is you are hearing, but I feel sure it isn't the leak of a pulled or broken stud! You would DEFINITELY hear the 'spitting' or 'head/cylinder slap' noise idling, and under power off idle. It sounds similar to an air compressor laboring, which your engine is, in fact!

Carbueted and MFI engines change 'note' when the engine comes 'on the cam' and it is very distinctive, and pleasant, and directly related to tuned intakes and exhaust being equal-length! I'm not sure that a CIS engine makes anything comparable, note-wise, since the intake runners aren't equal length.


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Warren Hall
1973 911S Targa

Does it lose power?
It may be your timing is off and you are experiencing detonation

Heard that 930s steering wheels solve that problem, also increases red line to 7200 brap, brap, brap.

OK smart ass, very funny.
Not it dosen't loose power, and it does have a cool sound to it. I just thought with all of this fear of pulled/broken head studs goin' round that maybe I should ask. Geez, I was just a little concerned. I have never heard first hand what kind of noise it makes when one pulls or breaks. So am I to take it Warren, that you can tell that one has failed by just listening to it at idle? I was rationalizing that perhaps at high RPM that the stress on a cylinder running on only three studs might leak or blow by and make the noise I was hearing...
So nobody elses SC makes a deep growl like mine?

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Leland Pate

___79 SC Targa

Lee, Yes, it can most definitely be heard at idle, especially if you are off to either side of the car 30 feet or so, to get away from exhaust and fan noise. It is VERY noticeable to a bystander if you drive by with the engine under load, say, in 2nd gear not under acceleration, just normal street speed of 30 mph.

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Warren Hall
1973 911S Targa

You worry too much, Leland. I recognize this easily because I do the same thing. It's a kind of neurosis, hearing about symptoms and then thinking you have them.

My SC whines beautifully, especially now wiht the new tensioners. Like a turbine or something. Then, if I stand on it, particularly at the higher RPMs, the engine growls. Pretty convincingly. It starts as a very low, deep growl which becomes that "bbrraaaattt" noise all good engines make when breathing hard. It's a symphony I can't get tired of.

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'83 SC

YES, THATS IT!!!!!
Exactly superman...thank god I'm not alone. Now I just wonder what makes it do that?
And you are right I do worry a little too much...stemming from the fact that my car is my only mode of transportation, and the fact that it is now 21 years old. Being a relativaly new owner things like odd noises scare the hell out of me. And thats why you guys are here to put my petty fears to rest.
Thanks guys


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Leland Pate

___79 SC Targa