Erattic and retarding timing when held at rpm

Electrical & Ignition

  1. CrazyRalph

    CrazyRalph Member

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    Have not used a dial back. I have tried two different regular timing lights though. And they both give the same result.
    I have not checked chain yet. Only changed the diffrent ignition components as I wrote in my original post.

    The chain is only a few years old and does not have many miles on it. But I will get it checked once distributor is ruled out. Gonna check advance plate and springs first I think.

    Should there be a little up and downward movement when pulling on reluctor? Cause I can pull the top shaft (witch the reluctor wheel is attached to) up and down some.

    I am a newbie in trying to fiddle around with this stuff
     
  2. Fran Blacker

    Fran Blacker FBBO Gold Member FBBO Gold Member

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    Check distributor shaft wobble. Remove rotor and wiggle the shaft. Point distributor .006 max electronic ones not sure.
     
  3. JG1966

    JG1966 FBBO Gold Member FBBO Gold Member

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    I had a similar issue with my 340. I changed the spark plug wires and that fixed it. If that's not it, I agree with those who suspect the advance springs are the culprit.
     
  4. HALIFAXHOPS

    HALIFAXHOPS MSGT(ret) and MOPAR only distributor rebuilder! FBBO Gold Member

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    Yes there is a bit, not more than lets say .050 Watch that clip under the felt in the advance shaft if you go that far, they can fly away from you and not available anywhere new. It is seriously time to check the timing chain it is easy. Take the cap off and by hand turn the motor one way until you see the rotor move then go the other way and when it starts to move you can tell it should not be a ton of lets call it slop in the chain.
     
  5. Nevada dan

    Nevada dan Well-Known Member

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    BF0503D6-1537-49D3-A347-7DBD46F29CE2.png It may sound silly but did you lube the contact heel and cam
    Sometimes it’s just the little things
     
  6. HALIFAXHOPS

    HALIFAXHOPS MSGT(ret) and MOPAR only distributor rebuilder! FBBO Gold Member

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    Good call but his is electronic. Yes spring tension on points is important so is cam lube.
     
  7. Shorthorse

    Shorthorse Well-Known Member

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    As long as we're throwing stuff out there, what harmonic balancer are you running? The elastomer in an old harmonic balancer can fatigue over time causing erratic timing. Sometimes you can attempt to rotate a tightened belt and the outer portion of the balancer will rotate slightly or put a wrench on the crank and turn the motor while watching the crank pulley closely. Those aren't perfect tests but sometimes it's obvious.
     
  8. Beep!Beep!

    Beep!Beep! FBBO Gold Member FBBO Gold Member

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    Hughes sent this with the cam kit i I bought for the reason you're describing, I called to check what its purpose was for, maybe is the reason why you have the problem of the shaft moving and fluctuating timing

    16135258700178644640630820614350.jpg
     
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    • hunt2elk

      hunt2elk FBBO Gold Member FBBO Gold Member

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      Had that exact problem on a new big block build last year. The guy who built the motor had me ship it back to him in California. He tore it apart, changed parts to lower the compression because he thought that was the problem. Put it in the dyno, and it still detonated above 2500 rpm. That is when they found out the dist shaft was riding up and adding 10 degrees of timing. He put one of those collars in and solved the problem. Expensive education for him.....
       
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      • CrazyRalph

        CrazyRalph Member

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        I’m not sure but I’s deffinitely not anything new. Looks like it could be original to the block or there about. So I guess that could be potential cause of my problems
         
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