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Registered User
Join Date: Apr 2015
Location: Fife, Scotland
Posts: 42
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OK, what do you think - 79SC 'tinkling' noise on accelration
Hi folks, this is a Euro 79 SC targa with a relatively recent top end rebuild by a good guy and several 1000 trouble free miles since, valve settings and timing in spec when last serviced, with stock heat exchangers, a cat bypass and aftermarket muffler.
I am hearing a pinging/tinkling noise from the engine when I accelerate, most noticeable in lower revs in 3rd, it most sounds like the noise a patch of gravel makes when it pings off the wheelarch and muffler. That is what I thought it was at first but it happens when there is no road debris at all. It goes away at higher revs. The car is driving normally otherwise. I don't think this is detonation (I don't really know what that really sounds like though) and it doesnt sound shut-the-motor-off-right-now bad, but I don't want to do any damage if it is an early sign of something - any suggestions? TIA.
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65 356C, 78 928 5 spd, 79 911SC Targa, 89 964 C4, 99 996 Turbo, 03 Cayenne S |
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01-13-2020, 04:11 AM
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Slippery Slope Expert
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That sure sounds like pre-ignition to me. Maybe you got a batch of sub-standard fuel?
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“As new technologies become indistinguishable from magic, and I can no longer tinker, the magic goes away for me.” |
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01-13-2020, 04:48 AM
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Registered
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As Steam Driver suggested, maybe substandard fuel. I assume you are using the highest octane fuel available in your area? That's what your 911 needs to prevent Pinging.
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01-13-2020, 05:42 AM
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Get off my lawn!
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Detonation is a very bad thing.
The 911 3.0 and 3.2 engines (and the earlier engines) don't have any knock sensors. It is easy burn a hole in a piston with pinging. Check your timing advance but even more important, be sure to have good premium fuel in the tank. Running regular is a way to destroy the engine trying to save a few bucks on a tank of gas.
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Glen 49 Year member of the Porsche Club of America 1985 911 Carrera; 2017 Macan 1986 El Camino with Fuel Injected 350 Crate Engine My Motto: I will never be too old to have a happy childhood! Last edited by GH85Carrera; 01-13-2020 at 05:54 AM.. |
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01-13-2020, 05:52 AM
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Registered
Join Date: Jan 2015
Posts: 98
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That's exactly what my motorcycle sounded like when I got gas from a certain station. I assumed they were doing something fishy with their premium fuel, like not actually having any on hand...
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01-13-2020, 06:10 AM
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Registered User
Join Date: Apr 2015
Location: Fife, Scotland
Posts: 42
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Thanks for the responses. It could well have all been on the same tank of gas thinking back. I'm going to re-check timing and switch to better fuel, I'll report back - it may be a while as the salt is really going down here after a mild winter so far.
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65 356C, 78 928 5 spd, 79 911SC Targa, 89 964 C4, 99 996 Turbo, 03 Cayenne S |
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01-13-2020, 11:02 AM
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Freddy
BEE
Carrera
