ARP Head studs

[valheru]

For those of you who worked with ARP head studs on our Subies, any tips and/or tricks for someone who never did.

Thanks

Denis

[STeveD]

Just because your new studs can handle higher torque doesn't mean that your block can. Overtorque the ARP's, and you'll strip the threads right out of the block.

[valheru]

Thanks Steve.

Maybe I should've been a bit more specific, any tips/tricks on installing the studs in the engine block (i.e. hand tight the studs, locktite, thread sealer, etc.).

[JoeT]

installing the studs into the block:

make sure the threads are clean in the block, (even though it doesn't say to do it) put a bit of loctite blue on the threads and finger tighten them into the block.

Note: ARP does not say to loctite the studs into the block, but from experience there has been some "backing out" of the studs so it's not a bad thing to do.

USE OEM HEAD GASKETS!!! NOT COMETIC, you don't want to retourque them after 1000 KM, it's a pain in the ass.

Torquing them down:
Use the factory torque sequence but "DO NOT USE THEIR BOLT STRETCH METHOD" of securing the heads. You will pull them out of the block.

use copius amounts of moly lube on the studs
Thread all the nuts on the heads hand tight at first (using factory sequence)
Torque them all down to 25 ft lba. again using factory sequence
Torque them all down to 50 ft. lbs
Then torque them all down to 78 ft. lbs.

Do the same to the other side, then let it sit over night.

The next day, check the torque of the head studs and retourque back to 78 ft. lbs.

Letting it sit for 24 hours allows the HG to compress and relax into it's final shape.

Hope this helps.

[Chris_Martin]

I think the biggest misconception is "finger tight".

Do they actually mean thread them in with your fingers? or toss the allen key in the top of them, and tighten them down "snug".

IMHO i'd go "snug", as that is generally the practice with all studs.



I agree with Joe on the HG recommendation...however only if you are using a 2.5L or WRX block.

The OLD headgaskets...like ones for the 2.2L are not yet MLS gaskets, and have not gotten all the improvements, superceeds, etc.

Cometics are fine, as long as you use them properly, apply some sealant, and have the heads AND block resurfaced.

[JoeT]

Yeah, Finger tights is kind of open ended.. Let's put it this way..

When installing the head studs, use a small torque wrench and tighten them down to 5 lbs ft.. That's more like finger tight quantified.. LOL

[valheru]

My only issue is that, as per the OE service manual, the final tightening is done in degrees from a torqued starting point, not in ft/lbs, so how do I re-torque after 24 hours?

My engine is a 2005 EJ253, SOHC, n/a.

[JoeT]

Retorqing after 24 hours = back off 1/4 turn, then torque them back up to 78 Lbs ft.

[valheru]

So I go by 78 Lbs and not by degrees as stated in the service manual?

[Chris_Martin]

If it really is just a 2.5L n/a...that won't be pushed.

Use OEM Head bolts.

[STeveD]

He does track days, and I believe that it was his first leaky head gasket that prompted this rebuild.

I have used head studs if you want them. They've been torqued once.

[valheru]

Thanks for the offer Steve, but I already have a used set of ARP studs from Joe.

In two weeks time, my engine should be on my workbench having surgery for cams, HG, springs/retainers, timing belt, etc.

All the goodies for this season of Solo2, track and maybe some solosprint/ATTS.

[Chris_Martin]

If you got them...use them.

still though...even with those mods, and some track driving.

You aren't going to see anywhere near the cylinder pressures of even a Stock STi, so stock bolts would work and be more reliable.

The problem with the gaskets isn't the bolts/studs fault. It's the inherent problems with an open deck block...