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over torked head bolts

Discussion in 'Mechanic and Repair' started by jlslavey, Aug 3, 2007.

  1. jlslavey

    jlslavey LawnSite Member
    Messages: 9

    Started putting my Kohler engine back together, used my torque wrench for head bolts only to find out my wrench was broken and did not stop and recommended torque. My question is this, if I loosen head bolts up and re torque using a new wrench will the head gaskets be damaged to over torque? I did not try and start anything just found out my wrench was broken and I very sure I over tightened them. What shall I do, buy new gaskets and start over or loosen bolts and re torque?
  2. ffighter624

    ffighter624 LawnSite Member
    Messages: 4

    im not sure bout head gaskets on a lawnmower motor but the one i used when i rebuilt my truck flattened out after torquing so if they are the same then i say yes new gaskets and start over, but if it wasn't allot over torqued i wouldn't worry about it
  3. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 963

    I think the question is HOW MUCH?
    If I didn't exceed by 10%, I'd give it a try.
  4. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Use your new torque wrench and adjust it a little at a time until it stops clicking, This will tell you where they are now then verify how far over you went then use the 10% as Bill mentioned.

    Never loosen then re-torque to less than before.
  5. jlslavey

    jlslavey LawnSite Member
    Messages: 9

    thanks for the info, but sad to say I think I way over , was using a large torque wrench then I made the mistake of loosing all up then snuging down. Think I'll just go buy 2 new and start over, feel much more safer that way. If you do a leakdown test can you totally keep air from coming out around a valve? I lapped them and they look pretty good , but still getting air at 30 lbs pressure blowing out the intake ports and exhaust ports, haven't attached carb or muffler on yet> just curious if you can seal metal to metal air tight?
  6. P.Services

    P.Services LawnSite Fanatic
    Messages: 6,319

    i would recommend using new bolts if you don't plan on it, trust me the extra 20 bucks is worth it i just spent 4 hours trying to drill out an old one ez out snapped off in it now im royally f ed. bolts stretch dont reuse them
  7. jlslavey

    jlslavey LawnSite Member
    Messages: 9

    thanks, the kit I bought containded all new bolts for the heads.
  8. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Messages: 2,613

    Compression release?
  9. ed2150

    ed2150 LawnSite Member
    Messages: 174

    Even if you used new head bolts, they're "stretched" if you seriously over-torqued them. Don't use them, you're asking for trouble.

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