BBC Head stud torque?

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by JMatt, Apr 7, 2014.

  1. JMatt

    JMatt New Member

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    How high can I torque my head studs to try to keep from pushing out gaskets, etc?

    Merlin Iron block. Dart Aluminum heads. ARP studs. 7/16ths diameter.
    .081" thick copper gaskets. Block o-ringed. Heads grooved.

    Dart says 70 ft-lbs.
    ARP says 80 ft-lbs.
    World Products doesn't say.

    I'd like to go as high as possible without over-fatiguing anything.
     
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    Last edited: Apr 7, 2014
  2. buzillamini

    buzillamini Member

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    If you get the tune up right it wont detonate and push the gasket out. don't go past the 80 that arp recommended or you will stretch the stud and it will be junk.
     
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  3. WIZBANG

    WIZBANG Member

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    I've always used 70 ft lbs, never had any problem w/ 25 lbs boost ?
     
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  4. Bjs344

    Bjs344 Member

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    I've gone to 76 the last couple years without problem. Went 76 and 70 on the short ones this year because I read it on the internet somewhere. The studs have been around awhile. Mine was trying to eat cometics when I was spraying it, but I know I was rattling it because I even knocked the intake bolts out of it once or twice.
     
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  5. Wildcatracing

    Wildcatracing Member

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    head stud torque

    always run about 75 on a BBC with .060 copper gaskets upto 38 lb boost, no issues
     
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  6. GregM784

    GregM784 Member

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    The 7/16 stud has a max torque. I run mine at 75. This is a case of more is less. Stretching the stud beyond elastic will ruin it.

    More torque is a band-aid for something else. Possible tune issue.
     
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  7. Policy Peddler

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    O-Ring

    If you are having problems with the head gasket, can not find a tune up issue. O-ring in head receiver groove in block will hold more. I have seen it where I had to pry the gasket out of the receiver groove.
    If you still have problems, put o-rings in both head and block, a little different diameter.
     
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  8. ITS IN MY BLOOD

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    Might also be an issue that for the BBC a .080 copper gasket and thicker wont allow for the proper clamping and flatness for a compressed seal it needs with the o-ring and receiver groove.

    I would take a little off the domes or less compression height piston or a shorter rod and go to a thinner head gasket, These blocks are not a Chrysler hemi.


    :)
     
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  9. Policy Peddler

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    I have never had a problem with gaskets all the way down to .031, except when i had a head with out valley bolts, I have also found that the thicker head gaskets do not appear to "crush" as well when i remove them.
     
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  10. ITS IN MY BLOOD

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    Re read what I typed,.lol....

    Like I said .080 and thicker bad,.. the thinner the gasket the better (no problems)..!!!!


    :cool:
     
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  11. Policy Peddler

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    if you are talking to me, i did, and was agreeing with you!
     
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  12. TAF 316

    TAF 316 Member

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    just checking, but on your new gaskets are you torqueing them then backing them off and re-torqueing them?
    I know you are not torqueing them like I do on a fuel motor but a little peanut butter couldn't hurt if you have access to some
     
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    Last edited: Apr 10, 2014
  13. JMatt

    JMatt New Member

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    My process is to torque in steps to 70 ft-lbs. Then one at a time I loosen, then re-torque to 70 ft-lbs each stud, one at a time. I find I get about an extra 1/4 to 1/3 of a revolution when doing that. I believe it's the process of crushing the copper gasket down onto the o-ring. After I've done all of the studs that way I will do the whole process of loosening an retorqueing them one at a time, and again I might get another 1/4 turn. Since I'm not normally removing heads between rounds I may even let them set overnight and do the process a third time. I will loosen and retorque until I hit 70 ft-lbs without much additional turn of the wrench.

    My last gaskets were .072. I need to check total piston to head clearance (I just don't recall what it was at the moment) and maybe I'll drop down to a .062 gasket or even a .052 as my compression isn't that high to start with. Also, based on talking to ARP directly, I'm going to torque to 85 ft-lbs instead of 70. 70 is what Dart says. 80 is what ARP "officially" says. They thought 85 was reasonable but not 90.

    And while I don't use Peanut Butter like you guys, I do use the ARP Ultra stuff that's thick as anything and suitable for my much lower torque settings than you guys. I think I'm getting to the limit of a 7/16" head stud's ability to clamp.
     
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    Last edited: Apr 11, 2014
  14. TAFC 5 81

    TAFC 5 81 Member

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    Head studs

    Long ago I had a Rodeck 481 and a iron BBC spare. We converted the iron block to 1/2 in studs to fit the same heads used on the Rodeck, and it seemed to give it a better seal.
     
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