blown head gasket on new build questions

[fastblueufo]

So I blew a head gasket at 2500 miles on new build.
ej22t with 5857 turbo at 25psi on cometic. 027 thick gaskets. Using Arp head studds tq 30/60/90 ft/lbs.

The block was decked and heads surface cut. Are cometic gaskets not that great or something? What are you big power guys using for head gaskets and studds?

Car busted a heater hose so I repaird that. Filled with coolant only to have the car idle rough and spit coolant out the exhaust. Damn thing... kinda figured the gasket blew when the hose busted.

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[stu]

Just use the stock head gaskets, they seem to work the best. I like to use the copper head gasket spray and add a few extra ft lb on the two center studs.

[eg33GC]

your surface finish may not have been as smooth per cometic's tolerances

the gaskets aren't bad, they're so good that shoddy machine shops/idiot psuedo-builders here just bitch when their shortcomings result in failure.

[fastblueufo]

Originally Posted by eg33GC

your surface finish may not have been as smooth per cometic's tolerances

the gaskets aren't bad, they're so good that shoddy machine shops/idiot psuedo-builders here just bitch when their shortcomings result in failure.

I assure you it wasn't anything to do with the build process or mchining. I doubled checked the surfaces with a mac straight edge and was WAY within spec. Also used a digital snap on tq wrench. I was told by quiet a few peeple not to use cometic due to not holding boost past 25 psi.

[alcoolaid]

Built a few engines using oem gaskets, 29 psi no problems. Went cometic on most recent build and pushing coolant at 25psi. I'm not the only one too. Going with cosworth gaskets now. There's an article on motoiq comparing actual clamping load on oem vs cometic vs cosworth.

[fastblueufo]

Originally Posted by alcoolaid

Built a few engines using oem gaskets, 29 psi no problems. Went cometic on most recent build and pushing coolant at 25psi. I'm not the only one too. Going with cosworth gaskets now. There's an article on motoiq comparing actual clamping load on oem vs cometic vs cosworth.

I saw that article recently and the pics of clamping force between the three. Looked like cometic had the least clamping force on the clamp ring around the cylinder. I thought I read that cosworth was just coated cometics or is that wrong? I have used cosworth in the past with no issue at high boost. Guess ill be giving them a call.

Let's talk studds. Is there a better option than the standard ARP? One that doesn't need to be tq higher than 90 ft/lbs as that is what I had the tq plates at when it was honed.

[berdugo]

Originally Posted by fastblueufo

I saw that article recently and the pics of clamping force between the three. Looked like cometic had the least clamping force on the clamp ring around the cylinder. I thought I read that cosworth was just coated cometics or is that wrong? I have used cosworth in the past with no issue at high boost. Guess ill be giving them a call.

Let's talk studds. Is there a better option than the standard ARP? One that doesn't need to be tq higher than 90 ft/lbs as that is what I had the tq plates at when it was honed.

Check this out

http://forums.nasioc.com/forums/show...2313586&page=3

[fastblueufo]

While were on the subject, what about the spray sealants like copper sealant and hylomar? How many of you actually remove the rivet on the mls gaskets and clean between them before applying a sealant?

[Crystal_Imprezav]

Cometics are very picky when it comes to the RA finish of the decks.