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2002 2.5 RS-T
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3,814 Posts
round 2 of comparison - what are the pros and cons of each head gasket, what one do you feel is better, and what would you recommend for an ej251/ej257 build
the cometic is a bit thicker....so it will lower your compression slightly....

as for which on is better.....they both do their job well :)
 

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overdeveloped beater
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9,088 Posts
I've used Cometic exclusively in the last 4 builds I've done. The only issue I encountered was using the OEM STi thickness gasket on a phase I bottom end. It was too thin and allowed the pistons to kiss the heads. They came out in exchange for proper thickness gaskets and all has been well.

The Cosworth gasket is virtually identical to the Cometic, so take that into consideration when choosing.
 

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2001 RS Emerald Green Racekor
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2,095 Posts
Make sure you are installing and using the proper installation method for the arp's or they will fail.


"KIT # 260-4701 HAS 11MM STUDS IN IT. SO THE TORQUE WITH ARP MOLY LUBE
WILL BE 85 FT LBS. DO THIS IN 3 EQUAL STEPS, YOU WANT THE FINAL TO BE AT
LEAST 25 TO 30 FT LBS OF TORQUE. YOU DO NOT USE ANY TORQUE ANGLE WITH
OUR FASTENERS. IF YOU ADD AN EXTRA 90 DEG TORQUE TO THE STUD AFTER TORQUING IT TO 85 FT LBS YOU WILL MOST LIKELY FAIL THE FASTENER.

NOW THE STUDS WILL GO IN THE BLOCK HAND TIGHT ONLY NO MORE THAN 1 OR 2
FT LBS OF TORQUE. IF THEY GO INTO WATER YOU NEED TO USE A THREAD SEALER,
IF DRY HOLES THEN USE THE MOLY.
WITH A NEW STUD YOU NEED TO RUN IT THRU THE TORQUE CYCLE 3 TIMES TO
BREAK THE THREADS IN. WITH THE 4th TIME THE FINAL TORQUE.

THE KIT YOU HAVE IS A HIGHER GRADE MATERIAL THAN OUR REGULAR STUDS. REGULAR
STUD = 200,000 PSI KIT # 260-4701 = 220,000 PSI.
 

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MY99 GF4 EJ227 JDM 6spd
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5,278 Posts
round 2 of comparison - what are the pros and cons of each head gasket, what one do you feel is better, and what would you recommend for an ej251/ej257 build
For those engines, the STi HG works well no doubt. When you start pushing 500whp++ you begin to worry about the heads lifting. The STOCK HG seems to work very well. For my EJ22T build I use the '97-'98 EJ22E, which is a 3layer HG just like the STi HG. I have no problems with it, but I am only pushing about 300whp.
 

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2015 STI Crystal White Pearl
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1,931 Posts
I got a good question for you arp stud users: do you re-torque your studs every 1000 miles like some users do/claim?

I feel there's no need to, imo. I think by doing that, you're just weakening the head gasket. I mean c'mon, if arp studs are supposed to be 220,000psi strong, and proven to hold more pressure than oem, why would they need re-torquing after so many miles? we don't have to do it with oem bolts, yet with the arp's? I don't get it. thoughts?
 
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