jim2527

My timimg is set to 8 degrees initial with a digital timimg light. I change the timing light to 36 degrees to check mechanical advance and rev it slowly. The timing mark on the balancer is all over the place in relation to the tab. It will go from very advanced to retarded and back to advanced and all over. Its bouncing all over the place.

Right now I can only think of two things that will cause this:

1. Misfire
2. I'm not steady with the throttle and as the RPM varies the mechanical weights are opening and closing. The only problem with this theory is the timing mark should never cross '0' but it does.


BTW...I set the points with a feeler gauge and my dwell reads 43. I cant get the dwell within range.

Thanks,
Jim

sethjohnson71

What about the end play of your distributor shaft?

CA-Legal-Vette

Are you sure that the balancer isn't the cause? For the longest time I thought that my problem was with the distributor but then pulled off the old harmonic damper and found that the rubber had completely rotted away. The outer ring was almost spinning free.

jim2527

I guess I'll make that 3 things. How do I check that? Should I pull the distributor and wiggle the end by hand?

77BuffaloVet

first make sure that the timing light is only on the #1 plug wire or cap of the distributor and that is not touching any other plug wire or terminal on the cap. If it does it will read from both and it will bounce all over the place.

If that is not the issue then see the other posts so far (i.e. distributor)..

Good luck
Chris

Hvymtlc5

Make sure the plug wire is good... switch to another wire and see if the flash is steady (of course you can't take a reading like that) if it is you have a bad wire / plug. You may have a bad pickup on the light. After that it becomes mechanical.

lars

You gotta' fix this before you try setting the timing. Why can't you get the dwell in range - will the screw not turn..? You have to get 30-31 degrees dwell before ever attempting to set timing.

jim2527

Lars, when I turn on the meter it reads 45. After grounding it and touching the negative coil post it reads 43-ish. The screw turns (the point gap changes as well, verified with cap off) but the dwell reading doesnt change as I turn it.

jim2527

The wires are touching. I'll isolate the #1 wire.

7T1vette

If that doesn't fix your problem, you might suspect the timing light being defective....especially if the engine doesn't sound all that bad. If Timing was jumping around as much as you indicate, it should be running really rough. Borrow a light from a neighbor/friend and see what it shows.

jim2527

It runs rough. My distributor endplay is .045. Time to order some shims.

jim2527

A little update. I re-shimmed my distributor and the timing mark is steady as I rev the engine.

Thanks for the help,
Jim

lars

Then your meter has an internal; ground and is no good. Set the point gap to .016" when wide open and let it go - this will produce just about 30 degrees of dwell. Once set, re-verify timing since a change in dwell produces an equal change in timing.

jim2527

Lars, I'm using an Actron digital meter. Is there a meter you could recommend for very occasional use?

Thanks,
Jim

Donald #31176

Go on Ebay. Since point ignitions are obsolete there are lots a dwell meters there for cheap. Got a Snap On MT816 for $15 last year.