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Banned
Join Date: Apr 2004
Location: Portugal
Posts: 1,513
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Got some weird results while checking my timing
Finally went to check the timing today and I got mixed results...
Max advance never goes beyond 36deg which I think is ok. On other hand at idle with the vacuum hose off I get around 17deg (between the marks of 5 and 30) and I'm at the limit of the dizzy adjustment. If I plug the hose back, I get 5deg at idle (which is right). Any pointers ... ? |
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09-26-2010, 09:06 AM
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Senior Advisor
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Leave-the-hose-pluged-in..... Sounds right, without the vacuum advance/retard (depending what car you have) it is just mechanical and (not knowing year/model) that could be fine. How much change in the engine (sound, rpm, roughness) from when you unplug the vacuum to having the vacuum plugged in?
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08 Cayenne Turbo |
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09-26-2010, 09:12 AM
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Banned
Join Date: Apr 2004
Location: Portugal
Posts: 1,513
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The only difference I can find / hear is with vacuum plugged in, idle goes down...
Anyway, the confusion was that in the porsche workshop manual they mention that you should take the reading with vacuum unplugged, elsewhere I've read that the hose should stay in... So I guess it's right, nothing to do ... |
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09-26-2010, 09:38 AM
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Registered
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timing
The hose should be connected to the vacuum and then check the timing at idle. My 2.7L CIS is 5 ATDC. (after top dead center)
Then unplug the hose (plug it) and then check the timing at 6000 rpm my 2.7 is spec'd to be 35 BTDC +=3. some builders leave the vacuum line off and plug the advance and they set the timing at 32 at 6000. mine is that way.
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1975 911S Targa Silver Anniversary Edition |
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09-26-2010, 01:24 PM
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Banned
Join Date: Apr 2004
Location: Portugal
Posts: 1,513
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Ok, then my car is behaving according to spec.
But what would be the advantage of setting the timing at 32 ?? |
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09-27-2010, 12:50 AM
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Registered
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timing
the 32 btdc is what the engine builder recommended for my 2.7l. I would use the factory timing (my 2.7 factory is 35 BTDC. This is to be done at 6000 rpm.
Put on some ear guards and set it up. Get a haynes manual and waynes 2 books for your car.
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1975 911S Targa Silver Anniversary Edition |
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09-27-2010, 05:01 AM
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