3.0 ignition timing adjust

[poorshe911]

I have a '83 SC with a stock 3.0 motor. I checked the timing and it's at 5 deg BTDC with both the advance and retard lines plugged in.
If I un-plug the lines, per the manual, the idle goes up to around 1500 rpm's so I turned the idle down to 900 and the timing reads well over 5 deg BTDC (approx 15 deg).
Is my timing way off or are the lines really suppose to be plugged in for that year?

Thanks for any help.

Michael
'83 SC
'99 323
'06 530xi

[rgmrgm]

if your mechanical advance is working you probably have way too much advance at 5k rpm. should be 5 degrees advanced with both lines disconnected and plugged (i use golf tees). if you live at high altitude you can dial in a little more advance. 1-2 degrees for each 1000 ft above the first 1000 ft

[poorshe911]

rgmrgm,
THANKS! I'll use that process to set it and see how it runs.
I'll post my results.

[poorshe911]

I reset the timing to 5 deg BTDC @ 900 rpm's and it runs fine. I'm wondering why it was set the way it was. The PO was very particular about this car so I wonder if the distributor was re-curved and adjusted accordingly. Maybe I'll send him a note but I've had the car for 10 years so I'm not sure he would remember it.
The reason I was questioning the timing was a rattle noise at around 2800 rpm's during acceleration. My mechanic looked at it and said it may be a rod bearing so in disbelief I'm looking at other things until he can get at it to verify it.
Thanks again for your response.

[rgmrgm]

if you had too much advance the rattle could have been pre-ignition (pinging)

[poorshe911]

that's what I thought but (I forgot to mention in my post) the rattle noise is still there.
I'm absolutely sick about the thought of a rod bearing. The car has been meticulously maintained all it's life and has only 81K miles on it. I'm having a hard time believing it's a rod.

[Flat6pac]

You do need better than regular gas in the tank. You need to look at the vacuum hoses connection to the throttle body and make sure they are open and sucking. The vacuum retard side will vacuum at idle, put it on your tongue and you ll feel it suck. The other side you need several thousand RPMs to feel it suck.
The hose connections on the throttle body can be cleaned out with burning torch tips cleaner.
You should check the distributor to see youre getting all the movement you require.
Bruce

[poorshe911]

yep .. checked the hoses for vacuum and the advance retard seem to be fine.
I added an octane boost too.
The noise sounds like a high pressure exhaust leak or loose baffle. I can also hear it by just revving the engine quickly up around 2800 rpm's.. It won't do it with #4 plug wire removed.
There's a post from johnb911 with a similar problem.

[Johnb911]

Poorshe911

Had any luck.

I have been trying to track down for a while.

Spent three hours Saturday with a 10MM on every bolt around.
Found my drivers heat exchanger to be rattling when I hit it. Passenger does not.

That did not take it all away.

Paranoid is the word around hear.





Good luck.

[pete3799]

Head studs alright?

[Johnb911]

How d you check the head studs?

[pete3799]

Originally Posted by Johnb911

How d you check the head studs?

Pull the valve covers and take a look.