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Old 02-06-2013, 10:40 AM
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Originally Posted by vaughn bros View Post
Hello everyone. Me, Andy and Cory, my brother. We share the duties of keeping a 327 running for daily transportation. We have a small garage behind my house here in Hickory, NC. This problem 327 is in a 63 C10, 3 speed. My questions are, what should my idle timing be? I have engine at 820 rpms, manifold vac is steady at 15, holley 600 vac port capped, has a HEI, 350 heads and headers turbo mufflers.
I read on others threads anywhere from 8 to 12 BTDC. Our engine runs bad at 10 and is hard to get restarted after hot. Am I doing this right. 10 degrees on my digital timing light puts my balancer mark at Zero on chain cover tab? Thanks. Andy.
When you say it runs "bad" at 10 BTDC, exactly what do you mean? Are you talking about the performance on the road is bad or it's bad because it's hard to start, or ?

Does it run better at a lower or higher idle timing (idle timing is called initial timing)?

Besides the timing at idle you need to know the total timing (total timing is idle timing plus mechanical advance, but not counting vacuum advance), and at what rpm the total timing is all in by. To check the timing, you first have to remove the vacuum hose to the advance canister and plug the line so there's no vacuum leak. Only then can you get a reliable timing reading.

The vacuum advance should cause the idle speed to increase along with the timing seen with the timing light when you hook it up to a full-time vacuum source at the carb. A full-time vacuum is called "manifold" vacuum. Hooking the vacuum advance to manifold vacuum is usually preferred over ported vacuum. Ported vacuum is not there at idle, only there when the throttle blades are opened some.

With the valve adjustment on the lifter that you can push down, you want to set the preload with the lifter all the way at the top of its travel. If there's noise from that lifter after it's adjusted correctly, you may need to go into this deeper.

Last edited by cobalt327; 02-06-2013 at 11:05 AM.
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