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Thread: Proof torque for 11mm head bolts?

  1. #1
    boostaholic Turbo Mopar Contributor
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    Proof torque for 11mm head bolts?

    What is the proof torque for 11mm head bolts? 90 ft lbs? If one fails, should I just replace that one bolt or loosen all the bolts and go through the whole head tightening sequence again?
    Last edited by John B; 05-08-2013 at 07:01 AM.
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  2. #2
    turbo addict
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    I just re-used mine for the 5th or so time all went past 90 ft /lbs. I wouldn't worry but as for re-tourqing all of them it probably isn't a bad idea

  3. #3
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    Re: Proof torque for 10mm head bolts?

    Saying you re-useed them for the "5th" time tells us you should not re-use them. !!!!!!
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  4. #4
    Supporting Member Turbo Mopar Contributor zin's Avatar
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    Re: Proof torque for 10mm head bolts?

    Don't cut corners, re-torque all. Doesn't take much time and will give you peace of mind.

    Mike
    "The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry

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  5. #5
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    Re: Proof torque for 10mm head bolts?

    Quote Originally Posted by Johnny View Post
    Saying you re-useed them for the "5th" time tells us you should not re-use them. !!!!!!
    Why? If they hit the torque number needed they will hold just as good as new ones, I have never had a problem with them so until i do i am saving the $$ and re-using them

  6. #6
    Supporting Member Turbo Mopar Contributor zin's Avatar
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    Re: Proof torque for 10mm head bolts?

    If they AREN'T being torqued to their yield point, which they are supposed to be, they'll be fine, but other than measuring their length (and/or "necking" under the head) before and after torquing, you're taking it "on faith" that they'll be OK.

    In the end, what it comes down to is what you're willing to risk. Save a few dollars on new bolts, or risk needing a new gasket and bolts, as well as the time to change it all, assuming no other damage occurs when the gasket goes.

    Personally, I don't like taking chances, it's something that eats at me, I tend to worry about the potential "weak link"...

    I know folks "get away" with it, but personally I'd rather not take the chance...

    Mike
    "The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry

    Bad laws are the worst sort of tyranny.
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  7. #7

    Re: Proof torque for 10mm head bolts?

    ^^Yea like on a long trip....imagine what its GOING to cost you when it fails, not if it fails.

  8. #8
    turbo addict
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    I would like to know how many people have had failed bolts. And what happens? I assume headgasket blows?

    I never have had a head gasket fail I was running 24 psi my engine. Other things have failed after 3-4 years of beating on it, but not my gasket. On the flip side if people think the aftermarket bolts are just as good for 1/3 the price. I might buy a set more often

  9. #9
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    Re: Proof torque for 10mm head bolts?

    I've had an 11mm bolt break due to reusing them too many times. I've got away with 5 and on the 6th, it broke on the way home. The head lifts up and combustion pressures blow away the fire ring and get into a coolant passage (or whatever's closest) and it acts just like a bad head gasket, but much worse.

    No personal experience with the 10mm head bolts.

  10. #10

    Re: Proof torque for 10mm head bolts?

    Not being a smarta$$ but what has failed that you need to reuse bolts six times? Could save some money fixing that right then spend a little on bolts...lol....I dont like spending what I dont NEED to as well, I feel your pain over being nickel and dimed to death.

  11. #11
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    Re: Proof torque for 10mm head bolts?

    Two headbolts stretched in the bucket that I have 20 or so headbolts. No history on them.

  12. #12
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    Quote Originally Posted by trannybuster View Post
    Not being a smarta$$ but what has failed that you need to reuse bolts six times? Could save some money fixing that right then spend a little on bolts...lol....I dont like spending what I dont NEED to as well, I feel your pain over being nickel and dimed to death.
    Only had one failure the ring land cracked. All the other re-uses were changing heads or manifolds or turbos for performance changes not due to failure. Idk which cars have the 10 or 11 mm bolts. I think I will change them next time but so far i guess I have been lucky.

  13. #13
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    Re: Proof torque for 10mm head bolts?

    Not sure what year manual this is but it says you can reuse them
    Click image for larger version. 

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  14. #14
    turbo addict
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    Re: Proof torque for 10mm head bolts?

    I was having troubles and changing pieces pretty often, so I wanted to see how far I could push my luck. Even now the head bolts in my car are on the 4th use.
    Last edited by shadow88; 05-10-2013 at 07:54 PM. Reason: spelling

  15. #15
    Hybrid booster
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    Re: Proof torque for 10mm head bolts?

    Man,

    You guys have great luck.

    Try this on for size...

    Brand new box of Felpro's tonight. 4 bolts necked threads before torquing to yield/test torque.

    Decided it must be a bad box, pulled them all. Opened another box. 3 more out of that box necked instead of torquing.

    WTH kinda quality is that!

    CG

  16. #16
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    Re: Proof torque for 10mm head bolts?

    What do you mean by "necked threads"?

    Do you mean the bolts stretched?

  17. #17
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    Re: Proof torque for 10mm head bolts?

    Why are we testing new bolts? 11mm bolts should be torqued to 65lbs and turned 90* ... done. Since bolt stretch and angular torque are two different things, I never understood the reasoning behind this.

  18. #18
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    Re: Proof torque for 10mm head bolts?

    Yes, correct, the bolts never torqued. they just stretched. Never came close...as I applied the 1/4 turn they didn't seem to get tighter, just stayed the same. I then began double checking, removing, and observing the obviously "necked" threads.


    I always finish test all head bolt installations. You don't?
    I was torquing the bolts and they didn't feel correct at finish of yield. When you do enough of this stuff, you get a feel for it. Third 2.2-2.5 engine this year.

    I've found that if you set your torque wrench to 90-95 ft lbs, your in that neighborhood when you give the bolts the "angular torque" of one 1/4 turn. Actually last night, 95 flbs was just a hair short of a full 1/4 turn.

    Yes I chased and cleaned the threads in the block...extensivly...always. I always make sure the bolt holes are clean and clear.

    Yes, the bolts and washers were oiled lightly.

    No, I did not have this problem with the other 2 boxes of head bolts I used this summer.

    This was merely a "heads-up" to double check your new Felpro bolts...

    CG
    Last edited by chryguy; 10-03-2015 at 11:41 AM.

  19. #19
    Super Moderator Turbo Mopar Staff 135sohc's Avatar
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    Re: Proof torque for 10mm head bolts?

    Quote Originally Posted by puppet View Post
    Why are we testing new bolts? 11mm bolts should be torqued to 65lbs and turned 90* ... done. Since bolt stretch and angular torque are two different things, I never understood the reasoning behind this.
    Chryslers own service manual tells you to check them for 90ft-lbs minimum after the final torque + 1/4 turn… Not that I put all the weight in the world on those directions.

    I run mine down in smaller increments and torque directly to 90ft-lbs. recheck the next day after the gasket compresses and its usually dropped a few so I crank them all back to 90ft-lbs and call it done.
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  20. #20
    Supporting Member Turbo Mopar Contributor mopar-tech's Avatar
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    Re: Proof torque for 10mm head bolts?

    Quote Originally Posted by chryguy View Post

    I always finish test all head bolt installations. You don't?
    I always do, when installing 11 mm bolts I set the torque wrench to 105-110 ft/lbs. If they don't hit the number on the quarter turn I throw them out.


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