torque values

Lee Thompson

New Member
Joined
May 24, 2001
What is the prefered torque for mains?
Studs and splayed bolts. I wonder what values they were torqued @ when line bored from the factory.
All opinions or guesses are welcomed.
 
Lee,

I torque my main studs at 100 ft lbs and the splayed bolts at 60ft lbs. I've heard of people using more but I try to duplicate what my machinist uses. These values are with ARP moly lube.

Merry Christmas

Neal
 
I actually used 100 on the studs and 40 on the splayed bolts..duplicated what we used when align honing the block.
 
!!!!

40-- on the splayed? Isn/t that a little weak for a 7/16 bolt.
I was thinking more along the lines of 90-70 with ARP lube.
I don/t have the Buick Motorsports book. Was hopeing someone on here did.
 
Re: !!!!

Originally posted by Lee Thompson
40-- on the splayed? Isn/t that a little weak for a 7/16 bolt.
I was thinking more along the lines of 90-70 with ARP lube.
I don/t have the Buick Motorsports book. Was hopeing someone on here did.

Well, I'm looking at the BMS book, and even it's not all that clear back in the blue print section.

Says 100 for main studs and 70 for bolts. But it's not clear if they mean main bolts or splayed? It also doesn't differentiate between any of the blocks (stock/stage).
 
There are many factors that come into play regardind torque values. The fastener needs to operate in the correct range of stretch recommended by your fastener manufacturer. The tough part is to install the fastener in this means. Thread engagement, fastener finish[black oxide verses polished,etc.], type of lubricant used,and number of torqe cycles, all create variables. Torque wrenches need to be checked against a master guage. I find very few that are acurate. All of this needs to start before the final line hone. This will ensure repeatability with both the torque value and the proper concentricity of the main saddles upon final assembly.
 
Re: !!!!

Originally posted by Lee Thompson
40-- on the splayed? Isn/t that a little weak for a 7/16 bolt.
I was thinking more along the lines of 90-70 with ARP lube.
I don/t have the Buick Motorsports book. Was hopeing someone on here did.

Lee, you made me go back and read my notes...it was 50. :) The machinist who helped me do the align bore picked the value as we didn't have a definitive source either.

Dave, I wish I had a calibration standard for my torque wrench. I spent a few days calibrating them when I was in the AF..man, that was a boring job! ;)
 
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