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The BEST exhaust manifold bolts?

Discussion in 'Engine & Drivetrain' started by Derick, Jun 27, 2020.

  1. Derick

    Derick Full Access Member

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    Back in wintry 2018 I replaced both exhaust manifolds and all the associated bolts. Well a year and a half later and I have an exhaust leak again. 2 bolts have sheered off again. What is the best option for these damn bolts? Also had anyone use the thick graphite based exhaust gaskets that watchjrgo used on the old ford pickup?
     
  2. drakon543

    drakon543 Full Access Member

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    arp makes some good bolts.
     
  3. iamdub

    iamdub Full Access Member

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    What bolts did you use? Torque to spec?
     
  4. Derick

    Derick Full Access Member

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    If you're talkin to me....it was an exhaust shop that did the work so I can't say for certain.
     
  5. iamdub

    iamdub Full Access Member

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    Ah. Too many variables in that situation. Other than specialty applications (headers on high HP cars, etc.), I've always used the bolt kit from Dorman and never had a problem. I use the copper anti-sieze that I use on spark plugs and I torque to factory spec. I even used them on my 5.3 with the headers I just installed. It's possible that they over-tightened the bolts and the two different metals (aluminum heads and cast iron manifolds) expanding and contracting at different rates exceeded their elasticity. Hardware has engineered torque specs for a reason!
     
    ivin74 likes this.
  6. Derick

    Derick Full Access Member

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    Yeah I was figuring the same.

    These are the gaskets I was talking about. Since they are soft, I think they only torque to like 25 ft/lb

    http://catalog.remflex.com/
     
  7. iamdub

    iamdub Full Access Member

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    Factory spec for the manifold bolts is 18 lb/ft. Of course, that's with the cast manifolds, MLS gasket and factory bolts. 18lb/ft isn't much, so it's easy for someone doing it by hand to just crank down on 'em really tight. Tighter isn't always better, especially when you have lots of movement such as the expanding and contracting of dissimilar metals. It's why these engines have MLS head gaskets as well. IMO, if you have all factory stuff- manifolds, gaskets, bolts... then there's no need for fancy gaskets and hardware since the OEM stuff lasts well over 100K miles. I think your quick failure was from over-tightened bolts.
     
  8. Derick

    Derick Full Access Member

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    That's the one.. I knew there was an acronym.... But couldn't remember to save my life...
     
  9. Derick

    Derick Full Access Member

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    Yeah I know... But at the same time I acknowledge that tolerances weakened over the 13 years of its life..... So I figure these allow some 'error'.... I figure 50 bucks for a full set of these gaskets and some proper bolts, I feel like it should be good for quite a long time.
     
  10. Rocket Man

    Rocket Man Build It Better Supporting Member

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    I won’t use anything other than ARP. I never want to see another broken exhaust manifold bolt, and those will never ever ever break.
     
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