Why did thas cometic head gasket fail? (N/A KA24DE)

[krustindumm]

Torqued ARP studs to factory specs (62lb/ft), but it had a massive failure w/in 400 miles.

It was reused, got it from a friend because I needed one fast. (According to my friend) Cometic says you can reuse them if you use copper spray.

This was the first time i've had a head gasket fail after I installed it, and I've done more than I can count.

[neilsan]

man if you needed a head gasket fast i'd have gone to autozone to get a FelPro.

Looks like the whole thing is wet which would indicate it didnt seal properly. not that it blew out.

My guess is the ARP studs needed to heat cycle and then be re-torqued.

[janko]

Originally Posted by neilsan

man if you needed a head gasket fast i'd have gone to autozone to get a FelPro.

Looks like the whole thing is wet which would indicate it didnt seal properly. not that it blew out.

My guess is the ARP studs needed to heat cycle and then be re-torqued.

What is heat cycling and why/how do you do it?

[krustindumm]

ARP's had previously been heat cycled. Autoparts store was a week out on a head gasket.

My guess, was that it had been crushed too much already, the compression rings are nearly flat.

[krustindumm]

run the car to operating temperature, let it cool down, and that is a heat cycle.

Really, I see no point in it. The studs are installed lubed and torqued to preload the stud. There should be no change after a heat cycle.

[neilsan]

i was confused, i remember the fsm says to torque the bolts to a certain spec to stretch them then torque to full spec. Were the ARP's brand new?

fwiw im reusing the original head studs, did NOT retorque them, but used a felpro and its been fine for nearly a year of dd. Did you really even damage anything? or did it start making bad exhaust leak sounds and overheat?

[krustindumm]

Originally Posted by neilsan

i was confused, i remember the fsm says to torque the bolts to a certain spec to stretch them then torque to full spec. Were the ARP's brand new?

fwiw im reusing the original head studs, did NOT retorque them, but used a felpro and its been fine for nearly a year of dd. Did you really even damage anything? or did it start making bad exhaust leak sounds and overheat?

FSM states a TQ for use when tq angle gauge is not available

didn't really do anything. Just parked it one night, and the next morning it was blown. No power loss, odd sounds, or temp increase.

[wootwoot]

Was the gasket surface checked for flatness? Could have just been that

[ryan hagen]

for the cometics your block and head must be resurfaced to a fine surface, not a coarse one like many machine shops do, those cometics have very little crush so its gotta be perfect, no gasket residue, or scratches or it will leak.

[krustindumm]

Originally Posted by ryan hagen

for the cometics your block and head must be resurfaced to a fine surface, not a coarse one like many machine shops do, those cometics have very little crush so its gotta be perfect, no gasket residue, or scratches or it will leak.

hmm, factory surface, checked it (and it was w/in flatness spec. Cleaned it with a 3M gasket remover wheel, just like I always do. No way to check finish, but there were no scratches.

[NemeGuero]

what are your ARP studs? saturn mains? thats what the guy from ARP said I needed for my KA.

And probably just wasnt a good idea to re-use the gasket.