I have to change the bolts on my bellhouse?

Discussion in 'Mustang Chit Chat' started by Midlife Crises, Feb 19, 2020.

  1. Midlife Crises

    Midlife Crises Member

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    Looking through the 2020 IHRA rule book for little things that might get me dinged this summer and I find the part about not being allowed to use Allen head bolts to attach the bellhouse to the engine. The T56 mag. kit I installed in my 2010 GT came with a SFI approved steel bellhouse and Allen head mounting bolts. Not enough room to use a standard hex head fastener without some sort of spacer. Anybody else had to solve this dilemma?
     
  2. 86GT351

    86GT351 forum member

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    When you are dealing with NHRA tech just get your specific thread pitch on the Allen Bolt and change it to what they require. Not worth getting flagged in Tech.
     
  3. stkjock

    stkjock ---- Madmin ---- Staff Member Administrator Super Moderator S197 Team Member

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    are you racing in sanctioned events? or just test and tune fun runs?

    FWIW - i've been to NHRA tracks to race maybe 20-25 times, never saw a tech guy get under a car or over the top enough to look at the bellhousing
     
  4. 86GT351

    86GT351 forum member

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    True
     
  5. jewc75

    jewc75 forum member

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    We get checked for diapers now at our local track. They have gotten much stricter.
     
  6. Midlife Crises

    Midlife Crises Member

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    I have not been on a track in many years so test and tune is my focus. If it feels good I’ll run brackets. I have to trailer the car 350 miles one way so failing tech would suck.
     
  7. MrBhp

    MrBhp Member

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    Are you running true slicks? If not they are not going to be concerned about the bellhousing or the bolts that hold it on. At least not in my experience. But my local track techs are at times lax. Only if you run sub 11.50's will they begin to really check what they should. Even then it's laughable. When you go sub 10s they wake up. Bunch of hillbillies. All that being said, they are an IHRA sanctioned track.
     
  8. Midlife Crises

    Midlife Crises Member

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    I will be running 28x10.5x15 MT, ET Drags. I think the facility in Palmer operates under IHRA rules. I don’t know how picky they will be. This is a street able vehicle. I could put cats and DOT tires on it and run street legal. I just don’t want to travel 350 miles and not be allowed on the track.
    With all the T56 Magnum XL conversions I have seen mentioned I am surprised nobody else has crossed this bridge. It looks to me like a M10,12pt flanged grade 10.9 bolt the correct length will do the job. I’ll give that a shot.
     
    Last edited: Feb 20, 2020
    MrBhp likes this.
  9. Midlife Crises

    Midlife Crises Member

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    Received a set of grade 12.9, M10-1.5X40 bolts in the mail yesterday. 12 point small pattern flanged heads fit perfectly where an Allen head bolt would fit. Now we know.
     
    eighty6gt likes this.
  10. Norm Peterson

    Norm Peterson corner barstool sitter

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    Was any reason for not allowing the Allen head bolts ever located?


    Norm
     
  11. Midlife Crises

    Midlife Crises Member

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    I did not pursue an explanation. I suspect the keyhole in the Allen fastener reduces the strength in some way.
     
  12. eighty6gt

    eighty6gt forum member

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    no, it's dead material.

    idiots....

    at worst, use a hardened washer.
     
  13. Midlife Crises

    Midlife Crises Member

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    I’m confused!
     
  14. eighty6gt

    eighty6gt forum member

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    means on a bolt that size the tool pocket is probably inboard of the shear area for the head of the bolt. And if they don't like the contact area for a reduced diameter bolt head you could put a hardened washer under it.

    just frustrating is all. Maybe there's something I'm not considering. I'll ask some smarter friends.
     
  15. Midlife Crises

    Midlife Crises Member

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    I used grade 8 split washers on all the bell house bolts. Seemed to work just fine.
     
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