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Registered User
Join Date: Mar 2013
Posts: 173
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Kind of noise when I accelerating???
Hi friends,
I have a weird noises From the back of the car ( knocking noise) on my 1983 911sc when I'm accelerating only after I pass 4000 rpm, Anybody have any idea what this is??? I thought maybe it from one of the Axle Shaft  thanks tom 
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03-07-2014, 11:50 PM
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RaketeRot
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Passing 4000 rpm while in what gears. 1, 2 , 3? All? Neutral? If your basing this on an accelerating engine speed (especially only under a load) and not a drive train speed then what's your octane level? Bump it up or retard your ignition.
Your advance is full in at that point. Does the knocking taper off if you decrease load but maintain speed? Do you have the stock vacuum advance type distributor installed? If so vacuum should retard under load and if broken well. Timing is off. Does it look like this?
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1967 911R hybrid clone 1973 911 RSR - coilovers, 2.8L twin plug RSR cam engine. butt welded metal RSR flares and metal frame ducktail If it were easy, it would not require people of our caliber. Last edited by Draden; 03-08-2014 at 02:10 AM.. |
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03-08-2014, 12:48 AM
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RaketeRot
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1967 911R hybrid clone 1973 911 RSR - coilovers, 2.8L twin plug RSR cam engine. butt welded metal RSR flares and metal frame ducktail If it were easy, it would not require people of our caliber. |
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03-08-2014, 02:09 AM
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Registered
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I had a similar noise over 3500rpm and it was head stud but it could be your axle and agree whith DRADEN these distributor the advance are prone to seize or vacuum
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03-08-2014, 03:39 AM
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Registered User
Join Date: Mar 2013
Posts: 173
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Thank you friends
 Draden the Vacuum tubes of distributor are new, I have two pipes that connect to it, i try to get photo of the distributor , retard my ignition is done by Rotate the distributor on its axis and tune the ignition? I'll drive the car later today and check like you recommended exactly when I have the noise and I'll update you , pors1968 about the head stud that you say , its Should only strengthen them? I mean, to close them??? thanks tom Last edited by tom1975; 03-08-2014 at 04:14 AM.. |
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03-08-2014, 03:59 AM
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Registered
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The two thing you can do is compression test and take off your exaust valve cover and check if twelve studs are there.First do you have any oïl leak near cylinder barrel.
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03-08-2014, 04:06 AM
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Registered User
Join Date: Mar 2013
Posts: 173
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Quote:
I'll check again now that the noise started yesterday, maybe i have anew leak, i hope you are wrong 
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03-08-2014, 04:20 AM
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Registered
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No leaks it good news i am probably wrong.
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03-08-2014, 04:24 AM
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Registered User
Join Date: Mar 2013
Posts: 173
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ok
i look and my engine dry with no leaks this is my distributor |
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03-08-2014, 04:44 AM
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03-08-2014, 04:46 AM
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Registered User
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Posts: 173
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03-08-2014, 04:47 AM
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Registered User
Join Date: Mar 2013
Posts: 173
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03-08-2014, 04:48 AM
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Mo money = mo parts
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I doubt that it has anything to do with an oil leak. Pors1968 was suggesting you look at the base of the cylinder near the case to see if you had any oily residue on the case. It is not going to be dripping, just black residue on the case. This would be my top vote too, but you really need to look above the heat exchangers to see.
The compression test would confirm, or just pull the valve covers off to look for a broken stud.
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Greg 86 Coupe (stock - pretty much like Butzi designed it) 65 Ducati Monza 250 & 66 Monza Junior (project) "if you are lucky enough to own a Porsche, you are lucky enough" |
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03-08-2014, 04:54 AM
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Registered User
Join Date: Mar 2013
Posts: 173
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I will check that , thanks,
I remember now that the noise I had yesterday was when I drive on 2 or 3 gear and was very similar to the noise that apear when you start driving on second gear , I will do drive test later and update ... I thinking maybe one of my piston don't get spark ???? Or something like that ... I hope I don't have broken stud , If I opend the valve cover , do I need to buy new seal ? I never deal with porsche engines before. Thanks Tom |
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03-08-2014, 05:10 AM
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Registered User
Join Date: Mar 2013
Posts: 173
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Hi Friends, Yesterday I played some ignition wires before I did a test drive and everything is fine, the noise disappeared...
I was almost out of gas, the lamp came on and I went to the gas station (I use 95 octane). I have no idea if this is what solved my problem of noise, but anyway thanks everyone for the help... I hope noises will not return
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03-08-2014, 10:54 PM
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1986 Porsche 911
