.100 bae block cracked main caps

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by blownapex, Aug 7, 2018.

  1. blownapex

    blownapex Member

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    .100 bae block cracked main caps
    why do main caps crack up the bolt holes
    seems like side bolts are trying to pull it apart and they crack
    i have a cracked center main (thrust bearing main )
    all bearings look good

    do they need to all be replaced liken rods after so many runs
    thanks
     
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  2. blownapex

    blownapex Member

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    ok did a search and found most my answers i needed

    someone did say they dont torque side bolts to recommended 80lbs
    what should i torque to then
     
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  3. jay70cuda

    jay70cuda Member

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    75 runs those caps should be replaced. Depending on the tune up. If your hard on parts and squishing bearings id do it sooner.
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    You most likey are suffering from detonation.
     
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  5. sean70ss

    sean70ss Member

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    Anytime I have seen the caps crack is because of bad tune up. Its trying to hammer the crank out of the block. I would check the crankshaft as well . That is the 1st to go when the mains are cracking.
     
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  6. blownapex

    blownapex Member

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    75%od c screw 9600 rpm
    12.3 compression/41 psi boost/3.79
    brand new crank
    cadium still 3/4 around
    all bearings like new
    may have been from previous 128 od
    ive had them crack before
    they must have a life like rods

    do i replace all of them or just the 3 center ones
     
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  7. Randy G.

    Randy G. Top Alcohol

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    If you have an older block BAE updated their main caps. Call Jeremy and ask him about it. Best to get it from the horse's mouth. Not that Jeremy is a horse or anything. And I certainly mean no disrespect to actual horses. :)
     
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  8. sean70ss

    sean70ss Member

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    After 50-60 runs new caps and line hone. I have not seen any on the new billet blocks or cn blocks or nre. The older blocks are more porous. Me I want to leave no doubts ALL of them.
     
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