Anyone used ARP main studs?

[ssdurango]

Has anyone used ARP main studs? I heard the extra clamping force could egg shape your main bores. Is this true? Arp's site dosen't say anything about this.


Thanks,
Tom

[34blazer]

install studs and then line bore

[sprucegagt]

Has anyone used ARP main studs? I heard the extra clamping force could egg shape your main bores. Is this true? Arp's site dosen't say anything about this.


Thanks,
Tom

Yes. If you get the studs from WOT-TECH, it states that you must line bore the block.

[ssdurango]

Crap, I all ready put the whole engine together! Maybe I can plasti gage one of the mains to see if they did distort...

[pocket-rocket]

I wouldn't think you would clamp them down any more the stock and thought ARP was only for added strength anyways?

[34blazer]

on one of the engines i built i torqued the heads on and measured the mains. iirc there was anywhere from .003 - .005 distortion. ever since then i have the heads torqued on when i have it line bored.

[MidnightriderZ24]

like every1 said, a line bore will do the trick. its not like your torquing any more than factory, the arps wont stretch with higher hp and rpms.

[ssdurango]

I talked to my machinist, he says main bolts apply torque to the block which can distort the block to create the proper main bore size. Where studs apply torque to the stud nut area. He also said he almost never sees any distorted main bores when studs are used. Studs also have a higher clamping force compared to a bolt installed at the same torque.

>34blazer...What engine did you see this distortion on? If my mains distorted that much the clearance would have been taken up the crank would of be hard to turn over.

[z284pwr]

My GenII 3.1 has ARP head studs. They are actually Iron Head head studs so they have the notches cut into the heads so the bolts could be clamped down. Machine Shop didn't realize the difference until they were installed so they just "fixed" the problem, haha. No issues with them on the engine thus far either.

[SappySE107]

what do you mean by iron head head studs? The 2.8 iron head studs won't work on aluminum heads. The studs themselves don't care what material the block and heads are.

[34blazer]

I talked to my machinist, he says main bolts apply torque to the block which can distort the block to create the proper main bore size. Where studs apply torque to the stud nut area. He also said he almost never sees any distorted main bores when studs are used. Studs also have a higher clamping force compared to a bolt installed at the same torque.

>34blazer...What engine did you see this distortion on? If my mains distorted that much the clearance would have been taken up the crank would of be hard to turn over.

it was on a '109' buick 3.8 block. thats why i said iirc. its been almost 6 years since i had the machine work done.

[z284pwr]

what do you mean by iron head head studs? The 2.8 iron head studs won't work on aluminum heads. The studs themselves don't care what material the block and heads are.

I never did a whole lot of research on it so I may be wrong. I know the studs don't care what material the heads/block is.

I thought I had read somewhere that Gen 1 engine studs were shorter than Gen 2 head studs which prevented the Gen 1 studs from working on Gen 2 engines? The engine build sheet doesn't have a part number so I don't know for sure, I just know the edges of the heads have notches/cut outs so they nuts could be tightened down. Do the Aluminum head studs still require this and I just never knew about it?

[SappySE107]

The aluminum heads require no modification. The iron head main studs are shorter because they don't have a windage tray to deal with. You can use them on the newer stuff without using a windage tray if you really wanted to. The tray needs to have the holes opened up for the stud size if you use the windage tray with the longer studs.