Over the last few days, I've been fitting rod bearings to a crankshaft. This is a lot of installing the caps on and off. I've finished today and am happy with the fit, but through the process a number of the rod bolt threads failed, making me decide to purchase all new rod hardware. So, my question is, how many times can old rod hardware be used or how long will they last? Mike
It all depends on how they were treated over the years. To me, if the threads still have a good form and are not buttressed and do not appear stretched, I'll use them. Doesn't matter how old they are. Just matters what the condition is today.
I agree with Jerry. I will add though that it only takes ONE good over-torquing to wreck a bolt. Which is the concern I have with cotter pins. It is so easy to go from under torqued to over torqued. Yes I use Loktite. Have for many years. AND a torque wrench. I like 30 ft lbs for rod nuts
350 or other small block Chevy bolts and nuts work very nicely. Around here, most engine shops will just about give them to you.
Chevy 3/8 rod bolts and nuts, torque to 45 pounds. Clean, dry thread of course. This brings up the question; what effect dose Locktite have on the torque value? Should you reduce the ft lbs if Locktite is used? It's no longer a dry thread.
Well..... they seem to torque just fine for the first few times that the cap is torqued. But the fitting process requires the cap to come off quite a few times. And then some of the bolts start to yield as they are torqued, the first sign of striping. A total of 11 bolts and or nuts failed in this engine, which is something new to me. I've assembled a number of engines over the last umpty squat years and have never had a rod bolt problem. Enough belly aching about that. Chevy bolts, which I have a bunch in the garage don't have cotter pin holes in them, so I suppose lock-tite would be the way to go. I'll try that. Thanks for the info. Mike
"Chevy bolts, which I have a bunch in the garage don't have cotter pin holes in them"
Just use the self-locking nuts that the Chev bolts are paired with.
Mike, what torque value are you using? You may be over-torquing the rods. Model Ts don't require the higher torque values used on modern engines; the bolts can't take them!
If the bolts and nuts were oily you may be pulling them too tight to reach 30-35 FP's. Or the threads were marginal to began with. If you are not using a torque wrench remember, the longer the handle the more tightness is achieved to the point where you feel the nuts are tight. The Ford rod wrench is in the ball park of something like about 8+ inches long. That length will allow the average person to only be able to pull in the range of 30-35 FP.
They don't need to be terribly tight. Foot-pounds schmoot-pounds... I never use a torque wrench on rod bolts. If you're using cotter pins, as I do, concentrating on a torque value only confuses the matter since you never get the torque you want anyway, due to pin alignment.