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  1. #51
    I should add that a TTY or torque to yield bolt, by definition has yielded or is in the plastic deformation zone and should be replaced. Permanently stretched. Guess it could be reused, but I definitely think it would be risky and more likely to fail.


  2. #52
    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by davus View Post
    No, we’re working towards understanding the overall characteristic of a TTY bolt.

    It’s useful information I think. Not necessarily because it confirms whether we should or shouldn’t reuse Seadoo headbolts, but because it provides additional context to the questions I asked.
    From your first post:

    "Then, after 2005, for some reason, the manuals changed to specifically state that the bolts had to be changed."

    The 215 chargers made about 7 psi. boost (150kPa, the 185 charger made less boost, but more cylinder pressure than N/A). The X chargers (2008...produce about 10 psi boost (170 kPa) at 8040 rpm. Increased engine speeds via reflash, increases boost, placing additional stress on stretch bolts, sometimes exceeding the design limits.....blown head gasket.

  3. #53
    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by Team Bilford View Post
    I don't know the answer, but I want you to know that is the most articulate well asked question that I have seen in many years.

    I have limited experience with stretch bolts. There seems to be an appreciation for them in Europe. Torqueing and then turning X degrees seems so weird. Maule and some of the OEM head gasket folks say that it is necessary to use them on multi sheet head gasket designs.

    Interesting to see that BRP says that you can reuse them if within spec. I have never seen a spec used on stretch bolts in the automotive field, used? Replace. If the ARP bolts are not of the stretch design, have they caused any head gasket failures??
    Riva Racing's instructions for ARP head studs currently state to use 80 ft/lbs using the ARP lube, 85 ft/lbs if using 30W oil. That is sufficient torque for an X charger. That said, more boost will require a higher torque setting.

  4. #54

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    Quote Originally Posted by RobJ View Post
    I should add that a TTY or torque to yield bolt, by definition has yielded or is in the plastic deformation zone and should be replaced. Permanently stretched. Guess it could be reused, but I definitely think it would be risky and more likely to fail.
    "TTY" is a misnomer. Torque angle is engineered to be in the elastic region of yield curve, just below the plastic region, so unless overstressed it will return to length. That's why they have an uncanny ability to reseal when used with MLS gaskets and you lift the head with too much cylinder pressure after "burping" some coolant out. Been there a lot, lol. On the 6G72, the fat stock bolts will always outperform ARP bolts due to this. You can push them way harder because they will reseal even at 1300 WHP. On BMW I6's though, the opposite is true, where the smaller diameter TTY bolts are already right up to the plastic region at factory specs and you can't cheat them up. On the 1503, I've never had issues with head gaskets yet even at 25 psi on my 3076, so I've had no reason to play with it and find the limit and try things like pyramid rings or cut rings and get some real cylinder pressure numbers going.

  5. #55
    I tried to copy a torque to yield graph but was unsuccessful.

    When a bolt is in the elastic zone, the increase in clamping force with rotation is quite linear. Once in the plastic zone, the clamping force does not change much with rotation until it fails. The change in clamp force in the plastic zone does not change at the same rate as in the elastic zone. Having a head bolt in this area is desirable when different materials are used, such as an aluminum head on an iron block. The bolts can accommodate the different rates of thermal expansion while still maintaining the desired clamping force.

    So to answer the OP’s question, if a bolt was in the yield zone, it will have plastic deformation or elongation and I would not re use it. Lots of good info out there. Spend a few minutes on Google and you can decide for yourself.

  6. #56
    88-jac's Avatar
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    The fact of the matter is......

    There are hundreds, if not thousands of cases / examples of the shite stretch bolts failing.......

    There are no examples / cases of ARP studs in these engines failing....


    So why is this even a question? Why would you fit anything other than ARP studs? There isn't even much of a price difference between new stretch bolts and ARP studs..

    ARP STUDS - EVERY TIME!!

  7. #57

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    Quote Originally Posted by 88-jac View Post
    The fact of the matter is......

    There are hundreds, if not thousands of cases / examples of the shite stretch bolts failing.......

    There are no examples / cases of ARP studs in these engines failing....


    So why is this even a question? Why would you fit anything other than ARP studs? There isn't even much of a price difference between new stretch bolts and ARP studs..

    ARP STUDS - EVERY TIME!!
    Dude I appreciate your angle, but again this is not all about “what bolts should in use”.....this is largely about increasing my education in why there is so much debate around reusing head bolts.

    I agree that ARP studs have their place......and rightly so......but again just claiming “go with arp studs and screw the rest” was not the purpose of why I started this thread.

    Cheers!


  8. #58
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    The thread is pointless ��������

    The stretch bolts are junk...
    Used ones, junk! - bin em!
    Buy brand new ones, hit and miss, some are junk! Bin em!
    Just get ARP studs and be done with it ��������

  9. #59
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    And all this about measuring them is a load of crap an all..

    Been there, done that.. They measure within spec and then when you install them, theyre JUNK!

  10. #60
    88-jac's Avatar
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    And people bringing aeroplane bolts into it ������ let's compare a 90 cent BRP bolt to a 1000 dollar plus aero bolt ��������

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