River1

I'm getting ready to put a Coyote in to a 10th gen and I want to replace the bolts with studs. I was wondering is it really necessary to pull the heads to put the studs on? Why not just properly loosen all the bolts and then replace the bolts with the studs one at a time? Since I've never seen this done before I contacted ARP and thought I'd share their response:





we recommend cleaning the threads with a thread chaser and using new gaskets when replacing the bolts to studs. we see a lot of issues replacing the studs 1 x 1.


Best regards,
Art Venegas


Technical Support
Automotive Racing Products, Inc.
800-826-3045
ARP-bolts.com


It is the last comment of "we see a lot of issues replacing the studs 1 x 1," that I thought warranted being shared. I posted this here because these years cover the start of the use of the Coyote.

SALEEN961

iTrader: (1)

What are you planning for this engine that makes you want to replace the head bolts with studs but not replace the head gasket?

Replacing the bolts one by one without removing the heads can be problematic because you won't be able to clean or chase the threads easily. In a worst case scenario you might tighten the studs and hyrdrolock a few of them in their holes before they bottom out or overlook damage that would have been obvious had the heads been off. ARP doesn't want to warranty studs that weren't properly installed following their directions, it's that simple.

River1

It's a new engine. Zero miles on it. It's common practice in competition to back off head bolt torque to retorque the heads. This is what led me to wonder about switching bolts to studs without taking it all apart. I've dealt with enough head removals I'm not concerned about hydrolocking the studs. I can't blame ARP for not wanting to warranty their products improperly installed or used. I really wasn't concerned about warranty issues but I don't think contacting ARP for their opinion about doing this was out of line. I do think their answer was worth sharing though. I'm sure I'm not the first person to think about the efficacy of doing this.

Skwerl

If the engine has never been heat cycled then I feel it's fine to reuse the head gaskets. Same as bolting a head on then removing it again before the engine is completely assembled. You don't buy new head gaskets every time you want to double check something before the engine is ever cranked.

RLXXI

The reason why you can't tighten them, loosen them and then tighten them again because when you apply final torque to those bolts, you're actually stretching it. From the shop manual.

Cylinder head bolts must be discarded and new bolts installed. They are a tighten-to-yield design and cannot be reused.

The amount of pressure applied to the head gasket is a one time deal. Once you set it you leave it or replace it.
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River1

Exactly. One of the reasons for replacing the bolts with studs. ARP studs are re-useable.

EDIT: Forgot this, Not re-using a head gasket is not a hard rule. No OEM gasket can be re-used though.

RLXXI

How many engines have you built? I lost count 30 years ago.
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River1

Not again!

Please read this:

https://cdn.arp-bolts.com/instructions/256-4301.pdf

https://www.raceenginesnz.com/High-P...ad-Gasket.html

Of course most don't buy $500+ head gaskets or $600+ studs. If you or anyone else prefers to not accept what some people do everyday that's fine with me.