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  1. #21
    88-jac's Avatar
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    Quote Originally Posted by Sea Dood View Post
    You are not following the rules by the OP, which clearly say "no uneducated opinions"
    😂😂😂😂😂🤡


  2. #22

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    I reuse them, you can feel when they are bad and I have had new ones go bad. My snap on torque wrench shows me the final torque achieved after the stretch and you can see in the numbers a bad bolt and you'll feel it. Anything other than stock and I would step up to a stud kit.

  3. #23

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    Head Bolt reuse. Sick of conflicting stories and uneducated "Opinions"

    Quote Originally Posted by Sea Dood View Post
    This topic comes up quite often, maybe it has been 5 years since it last came up. You all are forgetting the purpose of the head bolts, as well as forgetting about expansion and contraction of aluminum. So let me educate you, again....

    The purpose of of using Torque To Yield (TTY) bolts is to provide a uniform clamping pressure over the range of operation temperature cycling, and over time.

    Here is how this works:

    - When you reach the yield point of the bolt (the angle setting), the bolt has its limit of clamping pressure.
    - This yield range stays relatively stable as expansion of head and block occur over temperature
    - This yield range stays relatively stable over time

    ARP and other aftermarket studs don't work the same way. Yes, you can achieve much higher clamping pressures, which are good for higher horsepower, modded applications. But these are not stable over temperature and time. The clamping pressure can vary over temp range and over time. This is why you need to retorque these studs. For performance, and if you maintain your ski to include retorque, sure studs are great. But they are terrible for the average user, and terrible to use if you are not going to be managing them over time.

    The TTY head bolts that BRP uses are reusable, just like the ones that Mercedes and other high end manufacturers use. Why did BRP change the specs later on? I suspect that they got a lot of shade tree mechanics that didn't understand how these work, and many never measured the bolts and simply reused them. (it is kind of like the warning stickers they put on the skis "NEVER CHARGE OR BOOST BATTERIES WHEN IN THE SKI!" It is perfectly fine to charge or boost your battery in the ski. They put this warning because of all the idiots that hook up the charger or jumper cables backwards...)

    FWIW, I have personally found a number of head bolts that reach a yield point less than others. (when you have been wrenching for almost 50 years, you can tell by feel) I have found this with brand new bolts as well. I don't know if it is a quality issue or what. When I have come across these, I simply toss them. (BTW, they came out with TTY bolts during WWII for aircraft engines. They taught the mechanics how to determine the proper yield point by feel, not by torque.)
    Thatís an awesome reply. Thanks very much for taking the time to provide input to the thread.

    Iím intrigued as to how you can feel when a bolt has reached its yield point? Iíve been working on car engines for many years, but have only rebuild half a dozen or so Seadoo engines. This is my first introduction to TTY bolts.

    I can understand how youíd see it if you were torquing to a number.......I guess youíd just never get there, but when using a degree wheel for the second and third steps Iím not sure.

    The last engine I put together had head gasket issues from the word go. Iím wondering if it had a bad headbolt or two, and I just didnít realize.

    Dave

  4. #24
    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by Sea Dood View Post
    They taught the mechanics how to determine the proper yield point by feel, not by torque.)
    If I were flying an aircraft in WWII and a mechanic did that I'd have his ass......and I highly doubt this is truth. Not saying it didn't happen.

  5. #25
    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by davus View Post

    The last engine I put together had head gasket issues from the word go. I’m wondering if it had a bad headbolt or two, and I just didn’t realize.

    Dave
    That's exactly why stretch bolts should NOT be reused!

  6. #26
    ptscon's Avatar
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    This thread is way too long.

    Service manual has been saying NOT to reuse head bolts for the past 10+ years, that's a pretty good sign it should not be done.

    If you're modding for higher RPM/boost get ARP studs, if you're just doing a stock build get new OEM bolts.


  7. #27
    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by ptscon View Post
    This thread is way too long.

    Service manual has been saying NOT to reuse head bolts for the past 10+ years, that's a pretty good sign it should not be done.

    If you're modding for higher RPM/boost get ARP studs, if you're just doing a stock build get new OEM bolts.

    Correct! But some people will continue to cut corners to make a buck, or are simply cheap!

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  9. #28

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    Quote Originally Posted by 1tommygunner1927 View Post
    That's exactly why stretch bolts should NOT be reused!
    Mate, they were new bolts. Iíve never once said I re-used old bolts.

  10. #29

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    Quote Originally Posted by ptscon View Post
    This thread is way too long.

    Service manual has been saying NOT to reuse head bolts for the past 10+ years, that's a pretty good sign it should not be done.

    If you're modding for higher RPM/boost get ARP studs, if you're just doing a stock build get new OEM bolts.
    Youíre missing the point. Iím not saying itís right or wrong to use new head bolts, Iím looking for educated responses.

    One of the questions was why BRP changed their stance on it. This may not intrigue you, but it does intrigue me.

  11. #30
    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by davus View Post
    Mate, they were new bolts. I’ve never once said I re-used old bolts.

    See post 10......It too was a new stretch head bolt. It broke mid way through the torque sequence at 65 ft/lbs (88 Nm).

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