Author Topic: Fel Pro - gray bolt prep..  (Read 310 times)

dutch

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Fel Pro - gray bolt prep..
« on: May 06, 2015, 01:57:31 AM »
I assembled an engine a few years ago using Fel Pro gray bolt prep on the head bolts and never retorqued the bolts - although the head gaskets (also Fel Pro) were a type that specified as not needing it to be done.
Question - does anyone know if gray bolt prep remains flexible and useful enough to allow bolts to be retorqued at any point.
I do recall that it did specify that head bolts could be retightened after the first heat /cool cycle using it - but does anyone know if it would be possible even after a couple of years of moderate use - or will it have hardened up to a point where any additional tightening will just create more problems than it might fix?
Thanks - my understanding is that it is no longer available, if so are there any best alternatives to it? - Randy
 

JohnZ

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Re: Fel Pro - gray bolt prep..
« Reply #1 on: May 06, 2015, 04:16:27 PM »
I assembled an engine a few years ago using Fel Pro gray bolt prep on the head bolts and never retorqued the bolts - although the head gaskets (also Fel Pro) were a type that specified as not needing it to be done.
Question - does anyone know if gray bolt prep remains flexible and useful enough to allow bolts to be retorqued at any point.
I do recall that it did specify that head bolts could be retightened after the first heat /cool cycle using it - but does anyone know if it would be possible even after a couple of years of moderate use - or will it have hardened up to a point where any additional tightening will just create more problems than it might fix?
Thanks - my understanding is that it is no longer available, if so are there any best alternatives to it? - Randy
 

I don't know for sure, but I've built enough SB Chevy engines with Permatex #2 on the head bolt threads to learn to leave them alone. Why fiddle with them after all that time and risk breaking the thread seal in the deck?
'69 Z/28
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L78 steve

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Re: Fel Pro - gray bolt prep..
« Reply #2 on: May 08, 2015, 04:45:22 PM »
I agree. If it ain't broke. I use #2 or ARP sealant.
69 Z/28 Dover White X33,ZL2,PS,M20,Std.int.04C
67 SS/RS Mt. Green 1W,2LGSR,3SL,4K,5BY,07C
70 Nova L78 Blk. Cherry,Sandalwood,M21,02B