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Old 03-05-2009, 11:29 PM   #1
Max Umbarger
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Default Tuning shops still recommend OEM head gaskets.

Of course we are not limited too as we know there are other options, but 3 local tuning shops to me have recommended that in the 300 WHP range (my 06FXT) OEM head gaskets are sufficient. I don't want to have them fail 45,000 miles again later.

My question is what is making them better the 2nd time around? As far as I know for the 06's there have not been a revision. Did the factory do a crappy job installing them, torquing them improperly? OEM material failure? What gives. If it's workmanship I'm assuming a tuning shop will install HG's better to specs than at the factory right? In that case I'd consider going with another OEM set.

I will go with ARP studs this time around to negate any movement, but I've been considering Tomei HG's.

Thanks
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Old 03-06-2009, 01:37 AM   #2
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OEM's are fine as long as both the block and heads are decked ( flat surface machined ) and the ARP's are torqued correctly in the correct sequence. I believe its 40 ft lbs the first go around then 60 ft lbs then the final which could be 82 - 90 ft lbs.
I'm no engine builder but thats what I've gathered.
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Old 03-06-2009, 02:14 AM   #3
Max Umbarger
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Thanks for the info. I'm certain they will use the revised torquing directions.
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Old 03-06-2009, 12:37 PM   #4
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Here is a link about the product description...

http://www.tokyoseven.com/T7/product...roducts_id=499
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Old 03-06-2009, 12:45 PM   #5
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And it's better than stock because of...what exactly? I'd take OEM parts over aftermarket 99% of the time. I think it's more important that they use the correct head torquing technique than who made head gaskets. I always wondered if the arps stretched the same as the OEM bolts? It's the stretch of the bolt that keeps them tight.
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Old 03-06-2009, 12:47 PM   #6
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OEM head gaskets work just fine even at significantly higher power levels. We use ARP head studs torqued in 4 steps to 85 ft/lbs and retorqued the next day and have never experienced a head gasket failure. Of course we also deck both the head and block mating surface to the correct surface finish as well.
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Old 03-06-2009, 02:29 PM   #7
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Okay thanks for the info.
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Old 03-06-2009, 02:42 PM   #8
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605whp Stock gaskets. Not common for them to fail. I know one Friend/customer that lost one but that was 36 psi on Race fuel.

Clark
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Old 03-06-2009, 03:56 PM   #9
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Yeah, I think I'm going OEM. I'm thinking the install is important and a safe/reliable yet powerful tune can save the head gaskets.
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Old 03-06-2009, 04:55 PM   #10
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det will kill headgaskets if the pistons dont go first
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Old 03-06-2009, 05:16 PM   #11
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OEM + ARP HEADSTUDDS = STOUT

300 whp is nothing these days
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Old 03-07-2009, 11:18 AM   #12
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We use all OEM head gaskets and ARP head studs and have never had any HG issues. We also use copper spray on all of our headgasket prior to installation to help promote a good seal.

Tony
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Old 03-07-2009, 03:20 PM   #13
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Quote:
Originally Posted by socalLGT View Post
...We use ARP head studs torqued in 4 steps to 85 ft/lbs and retorqued the next day...
When you retorque the next day, do you usually find they've backed off a little due to stretch? If so, approx. how much?
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Old 03-07-2009, 03:29 PM   #14
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You guys don't polish the threads? When I did the HG on my Type-R motor, I believe it was arp that suggested loosening them 90 degrees and tightening them again several times to polish the threads and get a more accurate torque reading. I know for the same torque, the stopping point on the torque wrench kept moving as I did this.

I assume you're using ARP stud lubricant when you do this (I think it's just assembly lube).
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Old 03-07-2009, 08:38 PM   #15
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Old 03-08-2009, 04:41 AM   #16
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OK. I went with OEM. Like I said tho... ARP studs. I need to check my tune and make sure it isn't total chaos since I came from 6500' altitude 91 octane high output tune, into a low altitude 93 octane insanity tune (when I actually want a good reliable tune). I'm gonna check all of this. I don't want detonation to be a problem, granted I've never heard it on my FXT with an STi exhaust minus cats. Funny that I hear detonation on almost all American cars while I borrow them and they have quiet exhausts like my Forester...Who knows I only drive 'em while the FXT is down tho.

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Old 03-08-2009, 05:45 AM   #17
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Quote:
Originally Posted by cpunlamd View Post
C O M E T I C
Just to through it out there on my personal build i am running OEM head gasket. The engine is built to handle 1000whp and i have over 15grand into it.

all the true experts will recomend the stock head gaskets.

I am running a 74mm turbo with well over 40psi of boost.
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Old 03-08-2009, 11:48 PM   #18
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Dang! What's the problem with the failures then. At the assembly line?
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Old 03-09-2009, 11:05 AM   #19
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Quote:
Originally Posted by Max Umbarger View Post
Dang! What's the problem with the failures then. At the assembly line?
I won't pretend to know the exact equipment or procedure in the Subaru plant, but I know what they do when building the engines where I work (off road OEM).

An operator takes prepped (lubricated) studs and puts them in place by hand. He then activates the automotied assembly which comes down with independantly mointored and torque controlled sockets which run down the studs overtorquing them to yield, then backing off 2 turns, then resetting proper torque on all studs simultaniosly.

Obviously, it is still possible to have some issues, but if Subaru runs an similar process, then I doubt they can be accused of just sloppy manufacturing. Is there a tiem period where head gaskets are suspect? Usually, issues like that show up in batches.

Anyone's favorite name brand gasket can fail given the right circumstance. I see cometic mentioned above, and its a good brand...but a friend blew 2 cometic head gastkets while doing a light break-in cycle on a motor built to handle 1200+hp.
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Old 03-09-2009, 02:41 PM   #20
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I understand. Tuning plays a big role as well. Granted there are many EJ25's around with no mods and the gaskets are failing.
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Old 03-12-2009, 10:09 PM   #21
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Old 03-12-2009, 10:09 PM   #22
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Quote:
Originally Posted by Max Umbarger View Post
I understand. Tuning plays a big role as well. Granted there are many EJ25's around with no mods and the gaskets are failing.
Do it right the 1st time and remove all doubt.
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Old 03-12-2009, 10:35 PM   #23
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(Comment held because I am not a "factory" 2.5L turbo powerplant)

(And no, the mods didn't insert that)
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Old 03-13-2009, 12:45 AM   #24
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HaHa! STImedic. I've party'd it up in Fayettenam! I think the place was called Jumpers.
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Old 03-13-2009, 12:00 PM   #25
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Quote:
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You offer no redeeming value to this thread.
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