Exhaust manifold broken bolts

[Rawze]

(07-18-2021 )Lead_sled Wrote:  So, I’ve found while searching that this seems to be a common occurrence.

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cummins had an old TSB for this issue.. it is a common problem with older manifolds that are not drilled out quite far enough for proper heat expansion. here is the thread that talks about this and I posted the the proper reemer to use...
http://rawze.com/forums/showthread.php?t...9#pid39699

Also the #1 or #6 likes to snap exhaust bolts if the expansion joint gets severely rusted up and cannot slip in and out under heat loads. That is another common issue.

YES, the manifold is 3 pieces so that it can expand/contract under heal loads, and indirectly therefore prevent bolts from snapping ...
As well, After-garbage branded manifolds are often build as one piece and this is very bad, as there are no expansion joints.


WHATEVER YOU DO >>>!!!! The best way to prevent exhaust bolts from snapping ... NEVER EVER EVER EVER EVER EVER INSTALL THEM WITHOUT A TORQUE WRENCH!!... Always torque them exactly to spec so that they can expand according to specifications.

Personally, I also use a very light coating of anti-sieze on the bolt threads and shanks too, although the procedure does not recommend/call for it. I have always had good luck with them this way, and have not seen one break by doing this. I also use a very light coat of anti-sieze on the gaskets (both sides) too, to help them seal better. When I say "light coating", I mean "very light" coatings... like wiped a tiny bit on, coating everything, .. then off again with your fingers, no excess at all.