mlm0

I'm still chasing down a miss at idle. Without going through the whole list of things I have done, I can assure you I have done all the normal things and adjustments

I am down to egr issue, balancer issue, or internal leaking valve. Is there a way to determine if my balancer has slipped so that my timing adjustment is not correct. I have read several messages on this forum that this fixed the very same idle miss I have

1989 stock L98 with auto trans, 50,000 miles

ex-x-fire

Turn your engine over till the mark lines up on the timing tab large V notch, pop off the dist cap. The rotor should be pointed at #1 or 180 out.

BOOT77

I use a marked damper cover to check, but they cost about the same as a new damper. Is the rubber all cracked?

mlm0

Thanks, I'll give that a try, but how accurate is that, or will it be close enough?

mlm0

Have not looked that close yet. Is it just the outer part of the balancer that slips. I guess the complete balancer can't slip because its keyed?

Tom400CFI

That isn't very accurate, and if it's slipped, not accurate at all. You wouldn't know if the timing (distributor) was off (since you have a problem) or if the DAMPER had slipped.

Make a "J" shaped piston stop out of a coat hangar. Stick it in #1 cyl, bring piston up till hits. Mark damper. Turn backward until it hits again, mark damper again. TDC is dead center between your marks. Is that where you OEM mark is?

ex-x-fire

The ones that I've seen that have slipped were like 50 or more degrees out. Finding tdc through the spark plug hole on a sbc is a pain.
Another way to check it is to remove the crank pulley, line up the mark to the v notch & feel or look if the crank key is at the 1:30 position.

Cliff Harris

You can check your harmonic balancer by lining up a straightedge with the side of one of the spokes:



It's advanced from the groove by a slight amount. I don't remember the exact number, but it's something like 6°.