Std Head Bolts Limits?

Discussion in 'Turbo' started by pxr5, Dec 31, 2016.


  1. pxr5

    pxr5 Registered

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    Just been reading about stock busa head bolts being ok on a 400bhp streetmotor? sure good surfaces, gaskets & installation is key, what will the stockers handle? ( I thought up to 300? )
     
  2. turbojonny

    turbojonny Registered

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    Just making sure it wasn't my thread you were reading. If so, the motor was using APE at 400 before the rebuild and will now use ARP. I would fully expect stock studs to let go well before 400hp.
     
  3. shade

    shade Registered

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    ARP is the way to go. Super strong
     
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  4. Boosted Cycle Perf

    Boosted Cycle Perf Site Sponsor Donating Member Registered

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    If you've gone through the hassle and expense of building a motor, why skimp on good head studs at that point?

    I never reuse factory head or main bolts. I've had way too many stretch and not torque properly. If you start pushing head gaskets all the time and you're using stock bolts, you'll know why.
     
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  5. turbojonny

    turbojonny Registered

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    I had a Busa with stock rods that made about 290. The problem is that when rods arent up to the jobs you'll lose the head gasket. Big pain in ths butt to swap those out. Or, it will lose coolant and you might warp a head.
     
  6. hendrixgr

    hendrixgr Registered

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    I can tell with a great degree of confidence that stock bolts will stretch at 270-280 rwp given enough time (under 1 year) or with a hint of pre ignition (detonation at high rpm) and then the head gasket will go and the head itself will warp.
    I know from experience.
    Chris
     
  7. turbojonny

    turbojonny Registered

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    I know the frustration. You think all is good and then you smell coolant, and then its time to tear down the motor, then the head is warped.
     
  8. busakiller

    busakiller Registered

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    Don't you have pull the cams out to change swap out head studs?
     
  9. OZBooster

    OZBooster Registered

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    Yes , its not a straightforward swap one bolt for one stud and put the cover back on
     
  10. Boosted Cycle Perf

    Boosted Cycle Perf Site Sponsor Donating Member Registered

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    We had 20k mikes on our shop bike with stock pistons and rods marking 320hp with a RCC stage 2 ultra. Pump gas all the time.
     
  11. hendrixgr

    hendrixgr Registered

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    It can be done but not all gas station sell the same stuff especially outside US.
    What i am saying is that the stock head bolts will not tolerate any abuse especially on a hot 40+ degree Celsius day with the ambient air even higher.
    Chris
     

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