Timing cover replacement

Discussion in 'Small Block Tech' started by Richard Buckett, Apr 14, 2021.

  1. Richard Buckett

    Richard Buckett Active Member

    First thanks for helping me!

    I’m replacing my timing cover on my 70 350 gs ....before pulling the distributor I rotated engine by hand till rotor was pointing towards cylinder 1 on cap and harmonic balancer mark was on 0.
    I then removed timing cover expecting to see the dots lining up on the timing gears but the crank was at about 12 and the cam about 12 .....am I on tdc on exhaust stroke?
     
  2. 72gs4spd

    72gs4spd Well-Known Member

    You are correct.
     
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  3. sean Buick 76

    sean Buick 76 Buick Nut

    Next time remove the number one plug and stick a wine cork in there. Then you will know when it pops that you are on the compression stroke.
     
    Last edited: Apr 14, 2021
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  4. Richard Buckett

    Richard Buckett Active Member

  5. Richard Buckett

    Richard Buckett Active Member

    should I line them up to reinstall distributor?
     
  6. sean Buick 76

    sean Buick 76 Buick Nut

    I would still confirm TDC on number one by using the cork. Unless you don’t plan to take the timing set apart (or rotate the engine) in which case you can simply re instal the distributor as it came out, ensuring the rotor points the same way.
     
  7. Richard Buckett

    Richard Buckett Active Member

    great! thanks again
     
  8. Mark Demko

    Mark Demko Well-Known Member

    Incase it gets over looked, be sure to properly set oil pump gear end clearance to .002 AND pack it with Vaseline to ensue the pump primes.
     
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  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    If the engine was running at the time, and you lined up the firing end of the rotor with the #1 tower of the cap, then you are on the compression stroke. Valve timing and ignition timing are two different things.
     
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  10. 1973gs

    1973gs Well-Known Member

    Any GM that I worked on, both timing marks at 12 and 12 was on cylinder 1 compression. Both marks together means it's on cylinder 1's running mate, which on an 8 cylinder, is cylinder 6.
     
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