Rod Cap Measurements / Installation

Cape Codder

Cape Codder

Well-known member
I am in the process of tightening the caps on mains / rods with the motor in the car.
I have read in Les Andrews book to torque the Rod nuts to 35 ft. lbs. while Brattons catalog says 45 ft. lbs. Which is correct? ALSO when torqueing the the nuts which way do you go if the holes don't line up for the cotter pin, loosen or tighten? By the way Les Andrews book does not say anything about installing cotter pins after the cap is installed and torqued.
Thanks for your time.
Cape Codder
 
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The book I used says that the mains are torqued 80-100 ft. lbs. and the rod caps are torqued 40-50 ft. lbs. I'll have to do more "chart comparisons" as I find them. As for the cotter not aligning, you should be able to find the key hole by the variation in the torque values I listed, or try changing nuts. It has worked for me in the past when torque has to be "right on the button".
 
I try to get the rod nuts to 35 to 45 lbs, torque, and it depends on where the cotter hole lines up. Sometimes switching the nuts around helps. I try to shoot for about 40 to 45, but if I have to settle for 35 to have the cotter line up, I'm OK with that.
 
Pull Rods nuts to 40, then the key hole, never back a nut down to a key hole, if you missed it, back the nut down two turns, and retorque. Main bolts torque to 80 FT. Pounds, and pull the Key hole, any more you can have problems. Herm.
 
If you are not sure the torque of a fastener, there are many torque charts that will get you close enough so you never have trouble. I have filed the bottom of a nut to get it to line up with a cotter pin hole. It may not be correct but I never have had any trouble doing it. Also, for information only, torque by itself is not important. The amount of stretch on a bolt is what matters. Its just that torque is the easy way to measure the correct tension on the bolt. When I worked on Nordberg diesels, we used a micrometer type device that had a dial indicator head on it to measure the length of con rod bolts static and after they were tightened. They were large bolts that stretched about .090" when tight.
 
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