Stupid cometic head gasket!!!

[RacethisTSI]

Alright heres my story...a decked block and a fresh milled head(Two Brand New Mating surfaces). ARP head studs torqed to 90 ft/lb(also torqed from the middle out), and a cometic head gasket. Should be safe to run 20 PSI wright....nope. 2500 miles later after i built a fresh motor(from the crank up)... the head gasket blows....what im asking..is why?

 

[ddavisaf]

Did you retorque the studs after 500 miles?

 

[FullyBuiltDSM]

whenever your working with aluminum weather its a head or a wheel or anything you must check and re-check that what you tightened is still tight.

 

[92awddsm]

Did you torque to 90 psi using the moly lube supplied? If you just use oil to lubricate the threads, you need to torque them to 110-120ft/lbs. Also make sure you lube the washers also.

 

[RacethisTSI]

Yes i retorqed after 500 miles and yes i bought and used ARP moly lube

 

[ddavisaf]

I would say you've got excessive crankcase pressure then.
It sounds like you assembled everything perfectly, but something else went wrong.
Boost leak etc...

 

[RacethisTSI]

Wut else could have gone wrong to blow the head gasket

 

[poorboyj]

Wut else could have gone wrong to blow the head gasket

Too aggressive timing advance?

 

[RacethisTSI]

Timing was retarded all the way on my CAS

 

[badas93tsi]

I thought you had to have the block o-ringed and use copper o-rings to run a cometic gasket? Ive been having sorta the same problem.

 

[RacethisTSI]

Ive never that..i know you can o ring the block but with the cometic high pressure you souldnt have to. I did my research before percasing and spoke to the boys at busher, and they said the high presure was fine for a 20 psi set up so i dont know.