Head studs or head bolts??

[trbodon21]

I need a new set of head studs or bolts on my 4.1 considering I just blew head gaskets and the guy who built the motor put stock used head bolts in. With my set up and I plan on running around 20-25 psi with a set of cometic head gaskets what should I go with, studs or bolts. The thing is I still have AC in the car and don't plan on removing it so if I ever take the heads off again I would either have to pull the motor out first or remove AC system or can you get away without any interference?

 

[jastrckl]

studs and ac doesn't work out too well. some people do it, but I think you'll just be fine w/ some cometics and some new bolts. fire your engine builder. Your goals don't seem to require studs in my view.

 

[Race Jace]

the new ARP studs have an allen head recess in the end of them for easy removal to allow you to change head gaskets in the car if needed. I don't see any reason to use bolts now that they have done this.

 

[Ormand]

fire your engine builder

I second the motion. The stock TTY bolts are NOT meant to be reused, and will not reliably take adequate torque the second time. They will provide a definite safety margin, because they will let the heads lift at fairly low boost, thus protecting the internal parts. So, if you like to change head gaskets... reuse the stock bolts.

 

[Race Jace]

The reason i like the studs is this.

The production buick v-6 head bolt holes are counterbored to keep deck surface deflection to a minimum. sometimes these counterbore depths are not the same from one block to another. The weakest part of this connection is the threads in the block. With the stock bolts this does not make any difference because they have 2" or so of thread. ARP bolts and studs have 1" of thread to engage into the block threads. With the bolts you can't use up all of that 1" of thread on the bolt for risk of bottoming on the end of the threads before the load is distributed on the head of the bolt.

What we do to ensure we are not running out of thread before the bolt is tight is we install the bolt without a washer hand tight and make sure the head of the bolt seats against the cylinder head in each hole. since the washers are usually 1/8" thick this will allow at least 1/8" leeway. Also, when doing your check pay attention to when the thread starts to engage and note the distance between the bottom of the bolt head and the surface of the cylinder head it tightens against. this must be at least 5/8" or you can risk yanking the threads out of the block.

you don't have to do any of this checking with the studs. that is why we prefer them.

 

[Nick Micale]

The 4.1 uses different length bolts/studs than the '86-7 3.8 blocks. They may not have provision for allen wrench removal?

Normally, only the top row of studs on the pass side need to be taken out to remove the heads w/AC.