Torque spec
Thread Starter
Instructor
Joined: Dec 2005
Posts: 121
Likes: 2
From: Middletown Delaware
Torque spec
I was assembling a stock 350 bottom end (mains and rods) and instead of oiling the stock bolts I grabbed the ARP lube instead put just a little on each bolt and proceeded to torque them to stock specs 45 lb for rods and 75 lb for the mains. Have I over stretched the bolts? Should I re torque or replace the bolts? Thanks
Thread Starter
Instructor
Joined: Dec 2005
Posts: 121
Likes: 2
From: Middletown Delaware
Your right a stretch gauge is better for the rods but unfortunately I do not have one available. what I am looking for is if there is anyone on the forum who may understand the consequences of over tightening the bolts which is the net result of using stock torque specs with ARP lube.
Racer
Joined: Mar 2008
Posts: 428
Likes: 0
Did you torque the bolts to spec's just once? I usually cycle them through at least 3 times with the first cycle having the most friction. From the ARP web site I see that they recommend 5 cycles. Usually I torque using the lube the manufacturer recommended. Since you used the ARP lube, give them a call for a torque spec. If your going to be building engines in the future, buy a stretch gauge so I can borrow it 
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http://www.arp-bolts.com/Tech/TechInstall.html
.http://www.arp-bolts.com/Tech/TechInstall.html
Burning Brakes
Joined: Oct 2009
Posts: 787
Likes: 28
From: Fort Wayne Indiana
To measure stretch you can actually use a pair of micrometers instead of the fancy gauges available. In my experience using a stretch gage and comparing stretch versus torque using oil on stock rod bolts it almost always required more torque than was called for to obtain the proper stretch. If and when you exceed the yield strength of a fastener it becomes obvious because the shank diameter of the bolt will neck down and you will become unable to maintain the torque setting and of course it will eventually break. IMO you don't have a problem.
