Evo case assembly

Discussion in 'Engine, Fuel and Exhaust' started by karlsbike, Feb 3, 2011.

  1. karlsbike

    karlsbike Active Member

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    Hi all
    I am assembling an S&S 96 cuin engine for my Evo. Got the crankshaft & all main bearings in, the sprocket shaft seal is now in place and I've just closed the case halves. It all looks good so far!

    I've been following the S&S instructions carefully, but one question has come up: In other parts of the assembly instructions they are quite specific to note which type of threadlocker to use where, but for the case studs & bolts nothing is mentioned?
    This did not feel right, plus I wanted protection against galvanic corrosion (for the bolts). I therefore used blue threadlocker, as sort of a middle ground thing.
    What do you use - only anti-seize, or?

    Thinking about it, the bolts are really not stressed and the pre-tensioning torque is low (15-18 lbft). My concern is the vibrations as I do not want these to come loose. Maybe the cases act as 'springs' sort of like a massive spring washer?
     
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    My '91 Dyna manual does NOT call for any thread-lock either. But it does call for not hardening sealant between the halves. I assume the S&S does too.

    TQ
     
  3. HDDon

    HDDon Experienced Member Contributor Retired Moderators

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    I have rebuilt and built from scratch many automotive and motorcycle engines. I have never seen a requirement for any threadlocker on the studs or head bolts. The heat from the engine will cause the threadlocker to loosen and the torque will not remain constant. It is very important to follow the manufactures torgue requirements and this will be sufficient to keep the cylinders and heads to remain tight. If you have a question reguarding assembly I'm sure S&S tech support will be happy to guide you thru the assembly process.
     
  4. karlsbike

    karlsbike Active Member

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    Hi TQ
    Yes, S&S also calls for non-hardening sealant between the case halves.

    I really enjoy assembling a motor btw - since my wife reluctantly accepted that I build it in the basement (it beats freezing my fingers off in the garage).

    My argument was that it's only brand new parts going in - no oily stuff (almost true;)

    ================================================

    HDDon: I think we posted at the same time...
    So, are you saying that I should remove the threadlocker? I did follow the torque specs and the tightening sequence to the letter (the S&S cases have 3 interference studs that are going in first for accurate alignment of the halves).

    What about the bolts threaded into the cases - do you use anything to prevent galvanic corrosion?

    .
     
    Last edited by a moderator: Feb 3, 2011
  5. HDDon

    HDDon Experienced Member Contributor Retired Moderators

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    I'm sure some engine builders will say to use a nickel compound on the studs, but I only use some 30W motoroil. I have not seen any galvanic reaction at the stud/case interface. I would say a call to S&S to make sure, but I would not use a threadlocker on the studs or head bolts.
     
  6. karlsbike

    karlsbike Active Member

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    Thanks for the input.
    Since S&S calls for threadlocker on the cylinder studs (pre-installed by S&S on my set-up), I assume that given the right (heat resistant) compound is used it should be ok also for the case studs & bolts.
    The question is then more if it is of any use, and it sounds like the answer is no.
    The S&S case studs (3 of them) are interference fit, and for them I assume the ass'y lube I used for fitting provide corrosion protection as well.
    I was/am more concerned about the bolts that are threaded into the cases, and your tip about clean 30W engine oil is much appreciated.