Hey guys, i just had a question about the timing on my car...
i just got done putting in a used 350, pre 86. i have an HEI distributor with vac. advance. when i first installed the dizzy, the car started up ok, so i put a timing light on it to fine tune it. when i did i noticed the mark on the balancer was about 2-3 inches to the left of the timing tab, at about 12 o'clock. The car ran good in this position except for overheating on me. so i took my light and turned the dizzy until the mark on the balancer lined up with the 10 degree timing mark. the car runs good here also with a little hesitation, but i think thats because of carburation. does any one know why the car would run good with the mark wayyy off the tab and also when its on the tab? maybe the dist is off a tooth or somethin, and i was also thinking it was a different timing tab, because when i bought the engine there was a chrome TC cover. thanks in advance...

 

Disconnect and cap the vacuum advance while you set the timing.

Being off a tooth doesn't "affect" the timing. It is where it is when you adjust the housing, regardless of what "tooth" it is on.

What harmonic damper and timing cover did you use?

 

There's your problem right there. The timing tab is in the wrong place, as always with one of those. Whoever orders all of those stooopid things from the factory in China, should consider updating their drawing; SBCs haven't used that kind of timing tab since the late 70s.

Get the right timing cover. In the meantime, set it to where the car runs right, and ignore the mark, because it's wrong.

 

you said those tabs are from the late 70's. when i looked up my casting number, it said it was like a 69-80somethin block. could this be the right tab. I just didnt know why it would run in two different positions that are about 3 inches away from each other on the balancer, or does the timing have this big of a span, where it CAN run but still needs to be fine tuned. if my tab is correct, whats the stock degree. Right now i have about 10* advance. also, how would i be able to tell how much vacuum advance and mechanical advance i have? if i know i have 10* inital timing then how would i figure out the total timing degree? thanks alot for the replies.

 

The right timing tab has nothing to do with what block you use.

It's dependent on the harmonic balancer. So if you used your late-model balancer, you need the late-model timing tab to match.

In reality, you don't know that you have 10° of initial timing. Instead, you actually don't have the foggiest idea what your initial timing is, even though when you look at your mark it says 10°, because your mark is in the wrong place. About all you know is that if that combination of marks says you have 10° of initial timing, then you DON'T have 10° of initial timing, you have some other amount. It's somewhere about 25 or 30 degrees off. So if it says you have 10°, you really have about -15 or -20°, but I'm not sure what the exact error is.

So, the problem is, your tab is absolutely NOT correct, and its indcation is meaningless.

Set your timing to where your car runs right, and ignore the mark. If you are really concerned about the mark, or if you have to have it for emissions inspection, then either: go get the right timing cover; or get a balancer with a timing mark that matches whatever mark your timing cover has, which there's no way of predicting; or find TDC by observing the #1 piston's motion, and make your own mark on the balancer.

 

okay, thanks. i just asked that question because i thought it was weird that when i first fired the car up it ran good, but then when i got the light on it and i moved the mark about 3 inches it still ran good. the car seems to start better where i lined the mark up on the tab so i think ill leave it where it is, i must have gotten it close.

 

How are you guys seeing that mark or the tab - I can't see anything except the water pump and power steering pump....

 

take a white out pen and fill in the groove in the balancer, then you should see it. if you can do it somewhere dark like a garage or in the evening so its easier to see. ive done mine in the day but somtimes its a PITA so see it.

 

if you stand at the drivers side corner and look down inbetween the water pump and PS pump. right behind the pully thats on the crank. the tab should be located right above it or slightly to the right, mounted on the timing chain cover.