Stripped manifold bolt holes

[coach]

Rule of thumb is...as long as you have the same amount of threads deep as the diameter of the fastener...it's not going to be stronger by going deeper.
There are exceptions based on pressures or shear strength, but your just holding your plenum. The med or even short will work.


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[ikle]

Rule of thumb is...as long as you have the same amount of threads deep as the diameter of the fastener...it's not going to be stronger by going deeper.
There are exceptions based on pressures or shear strength, but your just holding your plenum. The med or even short will work.


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Ok thanks for the info.

 

[haywire4130]

I'm a machinist, sometimes when we make frequently disassembled parts out of aluminum we helicoil them right from day one... a correctly installed helicoil should never back out, and if you doubt their strength, tap a pair of 3/8-16 holes in a piece of 3/8 thick aluminum. helicoil one of them. Now take a grade 5 or weaker bolt, thread it into the aluminum side and tighten the hell out of it till it strips. Take same bolt in the helicoiled side and repeat. Guarantee the bolt snaps, done it tons of times. Helicoils have been around for ages for a reason: theyre awesome! You're not trying to seal any fluid, and its only 12 ft lbs-

 

[ikle]

Well today I finally had time to Helicoil the two stripped bolt holes in my intake manifold, it went so well I did all five. I used longer Allen head bolts for the two front and the rear center and used studs for the left and right rear holes, torqued them all down to 12 ft.lbs. I would like to thank everyone for all the help, you guys rock. Thanks again, Kyle.

 

[coach]

Well today I finally had time to Helicoil the two stripped bolt holes in my intake manifold, it went so well I did all five. I used longer Allen head bolts for the two front and the rear center and used studs for the left and right rear holes, torqued them all down to 12 ft.lbs. I would like to thank everyone for all the help, you guys rock. Thanks again, Kyle.

I did the fuel rail holes too. I have swapped out injectors 3 times ( stock to 42's, the 42's to 80's and then I stepped back to 60's) The threads were getting weak. Aluminum threads get weak. The only way to help them at all is to install studs so when tightening, the twist is on the stud and not the weak threads.