The object to check all 8 is to see if the shaft is tweaked.
Bouncing timing mark
- Thread starter JG1966
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JG1966
Well-Known Member
Thanks Dave. That's the first thing I'm going to do tomorrow (I'm done for today) is check it again and make sure my timing light connector on wire No. 1 is free and clear of wire No. 3. I kind of doubt it's causing it, but I appreciate every suggestion.
That's happened to me before...gave the timing light clip good separation and the flutter was gone...I hope that's all it is!
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Checking 4 is sufficient unless a discrepancy is found and if there is, no need checking any the reluctor any further.....
And JG, what kind of timing light do you have?
Yes I should have said every other one.
JG1966
Well-Known Member
Thanks Cranky. I have an Innova 3555 dial back timing light. Barely three months old. I thought I might have a bad light but it works perfectly at idle. Only at higher RPMs do I have timing mark bounce. I pulled distributor, and shaft and bushings are fine, reluctor gaps are good. The blade drive at the end of distributor and cam drive "slot" all look good. I switched out the stock "medium" spring for a light spring, checked all plug wires at cap and plugs, I separated the wires a little bit more and put it back together. Something I did helped. Timing mark still bounces at higher rpm but not nearly as bad as before. Next job is borrow a dial back timing light I know works and then, if needed, check timing chain for excessive slack. But I think I just need a new distributor (and maybe new wires). Distributor is stock from 1972, so I'm probably due for a new one anyway.
Last edited:
Shorthorse
Well-Known Member
Also check your harmonic balancer. Sometimes the elastamor layer can separate/fail and cause issues like you are describing. Sometimes you can just move it by hand or you can put a socket on the crank bolt and turn it. If the outer piece does not move exactly with the inner piece, the balancer is bad.
JG1966
Well-Known Member
Thanks Shorthorse. When I check timing chain, I'll double check harmonic balancer. I already tried to move it by hand and it wouldn't budge.
Daves69
Well-Known Member
While your at it, you might verify TDC and mark both the inner ring and outer for quick visual of slip.
JG1966
Well-Known Member
I wanted to post an update and thank everyone who helped out. It was the spark plug wires. I put in a new set (fortunately before I took time to check timing chain (which I was fairly certain wasn't the culprit) and timing mark is rock solid at all RPMs. Thanks again.
dave69's got it. Check the simple stuff.
Cornpatch MO
Well-Known Member
Bad timing light was what I was going to suggest..........................MO
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