ARP Main Studs

[tmsbuic]

I'm about to put my crank back in my engine and I need to know what the proper torque is for these studs(with ARP lube and with 30w oil). It's been about a year since I orginally installed them and I can't remember off hand. Also, are the studs themselves just screwed in hand tight and all the torquing is done with the nuts and washers? It would be great if someone had the exact instruction sheet handy by chance. Thanks for anyones help.

Tom

 

[Sam Colalillo]

Installtion method for ARP main stud kit per the instruction sheet:

Clean and retap all threads in block

Clean and inspect all hardware

Screw studs into block "HAND TIGHT ONLY"
Note: LOCTITE MAY BE USED IF A PERMANENT MOUNTING OF THE STUDS IS PREFFERED. THE FASTENERS, HOWEVER MUST BE TORQUED PRIOR TO THE LOCTITE SETING UP.

Install main caps and check for binding or misalignment

Torque the nuts to 90 ft lbs using ARP moly lubicant. or torque to 130 ft lbs with 30wt motor oil

 

[Blown&Injected]

130 seems high as the bolts are only 100 ft lbs and studs should take less.

HOWEVER, the proper torque specs are what the machine shop used when doing the line bore. They should have provided that info to you - call them before going any further!

 

[Lee Thompson]

torque

IMO, 130 ft. lbs. is WAY TOO much. Ever stop to think what effects higher torque values have on the rest of the block, such as oblonging the 2 center cam bearing bores===spun cam bearings. Those instructions in the box are not specific for a small V-6 Buick, they are general instructions. Admit it is is a small block Chevy world out there. I have always used 85 ft. lbs with ARP lube and that comes out to a higher value than factory. I believe ARP says when using their lube to use 75 percent of what the value would be with 30 weight oil.

 

[Sam Colalillo]

I was just copying verbatim what the ARP tech sheet stated, that is what he was asking for. I would agree with calling the machine shop and finding out what you should torque them to.

Yes, these engines stretch and move around when they are fastened together. This why no one should ever bore one of these engines with out using a honing plate to simulate the heads being bolted to the engine. Some people even claim that the main bearing clearance changes when the heads are bolted up to the block. The machine shop and I confirmed that they did not change on my engine before I assembled it. I have .0015 clearances on my main and rod bearings. When I picked my engine components up from the machine shop they had one tag tied to a connecting rod, and one wrapped around one of the main studs. These tags had the torque values they used when performing the machine work. They were the same as what ARP recommended. The machine shop also gave me the small moly lube packets that came with my ARP fasteners.

I am not going to argue how much more or less friction is created by different lubricants. These fasteners have a 190,000 psi yield strength. That has got to be higher than the factory bolts. These are ½ diameter studs they are going to distribute the load way better than the factory bolts with out distorting the block. Engineers use studs and accountants use bolts.

Lets talk about the torque wrench being used to fasten this assembly together. How accurate is it? When was the last time it was calibrated?

I am not going to argue with anyone, I am just going to say I agree with what ARP recommends. I know others will have different opinions, but this is mine.

 

[HellOnWheels]

I'm reading off the sheet that came with the studs.....

Torque the NUTS to 70 ft lbs using ARP MOLY ASSEMBLY LUBRICANT (or ARP THREAD SEALER) or torque to 85 ft lbs using 30w motor oil.

Install studs hand tight into block.

ARP also recommends that the studs/nuts be cycled (torque to specs, then loosen) at least 5 time before final torque is applied.

Use factor torque sequence.

HTH

HOW

 

[S10xGN]

How strange! I remember doing my ARP main studs (with their moly lube) at 105#... Wonder why all the different numbers?

 

[Sam Colalillo]

I'm reading off the sheet that came with the studs.....

Torque the NUTS to 70 ft lbs using ARP MOLY ASSEMBLY LUBRICANT (or ARP THREAD SEALER) or torque to 85 ft lbs using 30w motor oil.

Install studs hand tight into block.

ARP also recommends that the studs/nuts be cycled (torque to specs, then loosen) at least 5 time before final torque is applied.

Use factor torque sequence.

HTH

HOW

That is the torque values for an ARP 7/16 inch diameter head stud kit.

 

[HellOnWheels]

That is the torque values for an ARP 7/16 inch diameter head stud kit.

WHOA, my bad Sam, YOU ARE RIGHT!!! the 70# torque are for the head studs.
The main cap studs are torqued to 90 ft.lbs.

Sorry for the goof.

HOW

 

[tmsbuic]

I'm going with 90 ft/lbs., it finally dawned on me that is what I originally installed them at before. Thanks everyone for your help.

Tom