Arp head studs

SO it looks like the head gasket / cracked head issue as raised it's ugly head in my garage. Disappearing coolant, dead cylinder at start up that goes away after a few min, etc. Could be a lot of things but my luck will include pulling the heads.

So if that becomes the case, what is everyone's opinion of the arp head studs in our engines?

Yes I have a Kennedy chip and GM8 turbo, cooling upgrades, main stud girdle, etc.

It had head gaskets replaced under warranty and prior to the mods just before 100k. Has 215k on it now.

Big Green

If you plan to keep things at stock levels the TTY bolts are the way to go, and you need to use a new set..

Now if you plan to up the boost and fuel studs MAY be needed, but beware, if you use the sealer ARP recommends they will leak water through the threads and water down your oil...

I do use them in customer builds but I take several steps to ensure they stay sealed and don't leak water...

The recommended Fel-Pro head gaskets were engineered to work in conjunction with the Fel-Pro TTY (Torque-to-Yield) head bolts. These bolts provide for a somewhat elastic clamping load that automatically compensates for thermal expansion and the effects of time. Studs work great for a performance engine that is seeing extreme combustion pressures, but they aren't necessary for even a performance 6.5L turbo diesel because of the limited fueling capability of the DS/DB fuel injection pump. As a way of reinforcing that fact, we know that even the Duramax uses TTY head bolts.

Our 6.5TD Power Project engine (18:1 pistons, marine fuel injection system and all the rest) was assembled using Fel-Pro head gaskets and Fel-Pro TTY head bolts using Fel-Pro's and our own recommended procedure. That engine delivered perfect service approaching nearly 300,000 miles before it was sold to an out-of-state buyer. During that 7 year period and all those miles, the head gaskets were never a problem.

So, studs are not necessary on a 6.5. Personally, I'd put that stud money into a Holset turbocharger, for a much better return on investment... Jim

From everything I've read (no personal experience), using head studs on a 6.5L are very, very tricky to seal up and prevent coolant from leaking. I personally would stick with new TTY bolts.

Casey

I've built several engines with studs and never had one leak...

The only reason for a coolant leak would generally be up the threads on the studs.

Using a good sealer on the threads and the studs should be just as good as far as keeping coolant where it belongs as the TTY bolts are....The bolts get the threads coated with sealer as well...

Quote:

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Originally Posted by Big Green

SO it looks like the head gasket / cracked head issue as raised it's ugly head in my garage. Disappearing coolant, dead cylinder at start up that goes away after a few min, etc. Could be a lot of things but my luck will include pulling the heads.

So if that becomes the case, what is everyone's opinion of the arp head studs in our engines?

Yes I have a Kennedy chip and GM8 turbo, cooling upgrades, main stud girdle, etc.

It had head gaskets replaced under warranty and prior to the mods just before 100k. Has 215k on it now.

Big Green

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What year engine....

The late GM blocks did have an issue with some ...cracking the #8 cylinder at the rear near the head deck.
These would cause coolant loss and such but once the engine was warmed up things were so so...
Different than a blown head gasket.......

Get the heads off and look at the #8 hole for a stained gray area near the rear/top of the cylinder.

ARP studs are good stuff....but they will not fix the issue at hand.
The TTY bolts will hold well as Jim mentioned.

Also look at the area on the deck where the stainless fire ring of the gaskets sit against the deck.

The end cylinders are notorious for getting an etched groove in the deck near the end coolant passage....

If the deck has a groove worn in it......The only fix is to machine the deck and use the thicker gasket.......

Felpro offers a .010" thicker gasket for such a task.

I have machined the decks to .015" without issue......

This is not what you wanted to hear I'm sure.....But these areas need to be looked at.

Front and rear cylinders by the large end coolant ports need to be looked at carefully.....number 8 cylinder at the rear about 3/4" down from the deck (Just below the thickness of the deck)


Good luck

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