Timing Help, Please

[5String43]

I just set the timing on my car, an '82 SC. Thought I'd better - it's very hot and dry here today and I noticed that on full throttle, it's pinging like an SOB.

So I did the job, working only to setting the advance at idle. Found it considerably advance. I dialed it back.

But should the vacuum lines remaining connected when I check idle setting? Or should they be disconnected?

I'd be very grateful for the group's wisdom. I'd like to get this right. (Did a quick search, did not find the answer to be immediatly evident.)

Thanks - Jon

[Walter_Middie]

[James Brown]

^^^^^^See above and copy it ^^^^^put the copied page in your BENTLEY 911SC REPAIR MANUAL.

[5String43]

Thanks very much, gents. I presume that means BOTH vacuum lines disconnected.

[James Brown]

yes,

[5String43]

OK, redid the job, the settings were correct in the first place, which means that with the vacuum lines both disconnected and connected, the timing marks line up right where they are supposed to/right where they did before I started fiddling around.

Which leaves this question: Why is it pinging so badly? It's got to be running way lean, I figure.

Thoughts?

[Steve@Rennsport]

Originally Posted by 5String43

Which leaves this question: Why is it pinging so badly? It's got to be running way lean, I figure.

Thoughts?

Several reasons are possible and those include:

1) Insufficient octane: mis-fueling is not uncommon and this occurs when a gas station's tanks are mis-fueled with the wrong product. You should be using 91 octane fuel.

2) Sticking advance mechanism resulting in too much mid-range advance.

3) Incorrect fuel mixture.

4) Incorrect spark plug heat range.

[5String43]

Thanks, Steve. I'll check on all.