[GRN69CHV]

Decided to pull 2 pistons, noticed a vertical line in 2 cylinders. A I suspected there was a sharp edge on two rings left over form filing. Probably no big deal, but no sense in scoring fresh cylinders. While I had things apart, went back over all the rods and the mains - this time with a fresh tube of ARP lube that I picked up. Previous had torqued with 30 wt oil as a lube. Interestingly, at the rated torque values of 50# for rods, 100# for the mains, with the correct lube as soon as I got to the required torque values, sure enough, the nuts / bolts got tight, I could tell imediately, I had gotten to the point of bolt stretch. Torque with oil, the bolts still felt loose. In the case of the rods, I had them up to 55# with oil and they still hadn't tightened. Just goes to show how well this works and what happens when you do it with the recommended assembly lube.

PS- let me tell you what a relief it is to finally have a well prepped short block - ready to go.

 

[Bob West]

I've never used ARP lube, built 3 motors and none of them came apart Maybe the initial torque, then loosening, then retorque helped?

 

[GRN69CHV]

I typically just use oil, unless I have a new bolt set that has the lube with it. I was just surprised that with the lube, the bolts came to a distinct holt at the rated torque values, rather than progressively pulling tight. I think the underlying issue is, the lube takes the guesswork out of whether you actually got to the point of bolt stretch or not. When I used to do this regularly (long time ago) , it got to be second nature that I could almost torque down a main without a torque wrench and be darn close. Like anything else, you loose your feel for it.

 

[JIM]

Were you using a bolt stretch gauge on the rods? That pretty much takes any guess work out regardless of what type of lube is on the threads.

 

[GRN69CHV]

Don't have a gauge, I just measured with a dial caliper before / after tightening.

 

[1968 hot rod]

a good set of calipers are good for +/-.001 usually,rod bolts buy a stretch gauge or try to use mics