The Saga Continues: Head Stud and Gasket Discussion

Anyone know the conclusion to this whole story? Any chance we could get the three recommended installation methods for OEM or APR studs?

 

ARP has revised their instructions now, to an oem torque sequence I think

 

I'd like to see it.

Last week I had an 06 STi come in for a new block and such, customer said the head gaskets blew on it.

It had ARP's in it. Dunno what they were TQ'd to but they were tighter than the OE bolts.

It did have OE headgaskets as well and it was very clear to see the combustion leaks on both sides.

 

My block is gonna have OEM head studs after reading all of this.

 

Amen...I have read too many bad reviews on the ARP/Cometic combo.

 

Will, didn't you say that the ARPs were ok if the factory torquing specs were followed? I would think that with sti gaskets and ARP studs torqued with the factory sequence it might be ok?

 

I dont know what specs were used on this engine, it was assembled elsewhere.

However, there was ONE that I know of for a fact that was assembled using the ARP's and stock gasket and TQ'd per FSM specs...something else let go in the engine before the headgaskets/ARP's failed.

I would speculate....that I dont know for sure...but that it might turn out ok.

 

I mean there is no arguing that they are indeed stronger. It just seems that there is an issue with them backing out and loosening. I would think there has got to be some method that would allow them to stay in there...I mean the factory ones stay in there, lol.

 

Weld them.

 

Red Locktite in the block

 

We could invent some nanomachines to weld the head to the block....

 

Why get ARP's when the stockers are fine? The stockers don't stretch. That's why a lot of people get ARP's. For example the 4g63....stock head studs are really only good for one tightening. Then the stretch and you can't really safely reuse them. Subaru isn't the case there.

 

I would not reuse Subaru Head Bolts

 

Why not....they don't stretch at all so no problem.

 

Every bolt stretchs

The torque sequence of Subaru Bolts sure sounds like every other TTY fastner I have ever used.

 

Yeah it does. I'm just going by what WJM told me...unless he meant 'new' head studs.

 

SUBARU does not recommend replacement of the head bolts during engine overhaul/head gasket replacement.

There are lots of SUBARUs making power (stage2 to over 500whp) that have 2 or more TQ sequences on their head bolts with zero problems.

 

I have ARP's along with stock head gaskets on my TopSpeed RR1 using Doug's method. No problems here.

 

Matt, what was your method of getting the ARP's to work correctly?

 

Basically Dougs Method