Tapping in the engine

Discussion in 'The Bench' started by Paul A, Aug 15, 2019.

  1. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    Ur4 or 5 on any iron head will never hit the piston. Not even with domed or anything. Either your firing order was off, and had a lot of pinging . Or plug got messed up on install. Its all good whatever happened , weve all been there and worse probably.
  2. Paul A

    Paul A Active Member

    This entire situation has been a mystery to me from the beginning. I never heard of pistons hitting the spark plugs before but when I looked at the plugs after they were removed by the shop it was obvious something had compressed the plug gap to the point where there was no gap on 4 of the 8 plugs. I am 99% sure the plugs did not get messed up on install since I put them in myself. I gapped them to .045 and they all went in smoothly with no binding or any other resistance. However, now I am getting smelly white smoke from the right exhaust and I have the car back in the shop with them checking for a blown head gasket. It will be interesting to see what they find. Thanks for your comments. I appreciate it.
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I have heard of extreme detonation closing plug gaps. That will also blow a head gasket if you are lucky.
    Last edited: Aug 27, 2019
  4. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    It would be nice to know what holes the bent gaps were in. I would have looked for marks on those pistons. The bent plugs would have carbon cramed in them if it was from carbon crud. 45 is i bit big. But still would not hit. I prefer any gap straight accross not bent up or down. I would do a radiator pressure check that will let u know if you got head gasget leaking.
  5. telriv

    telriv Well-Known Member

    Pressure testing the cooling system lots of times will NOT pin point a head gasket or other cooling system leaks as max you can only go to about 20pds. except normally for hoses, radiator, heater core & hoses. To be certain you would have to shop air pressure each hole with the piston at TDC compression stroke. This will at least put 125-175lbs. in each hole. Been through this MANY times.

    Tom T.

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