Replace or Re-use the Connecting rod bolts

[Misdemeanor]

I am in the process of rebuilding my L134. Got it back from the machinist and I'm getting ready to put it back together. I am debating if the Connecting Rod bolts, nuts and lock nuts should be replaced. I am thinking there is no need. These are low compression over built engines but I thought I would ask some of the more experienced rebuilders out there and see what the standard practice is.

I noticed the threads on the piston pin lock bolts are distorted after take out. I will replace those. I'm not sure how they got chewed up but the eternal treads on the rod seem fine. Maybe that should be a separate post. Has anyone had that same experience when backing out the pin locking bolts?

 

[maddawg308]

I would replace them, even if they look okay. Old engine bolts that have any strain on them for decades, regardless of how nice they look, have internal stress that may not be evident by eyeballing them. Plus, your engine is apart now - wouldn't it be easiest to replace these fairly inexpensive parts now, while it's all apart?

 

[saddamsnightmare]

February 2nd, 2015.



No use risking a rebuilt engine to save a couple of bucks on bolts, which if they fail, will tear your engine apart!

 

[steelandcanvas]

I agree with Mike and Kyle. The insignificant cost of new nuts and bolts should definitely set your mind at ease.

 

[steelypip]

The only gotcha I'd add to using new rod bolts is to is either a) make sure that you source your new bolts from a source known (not just reputed - everybody offshores these days or has flirted with it in the past) to have good QC, or b) measure bolt stretch on each rod bolt as you tighten to spec torque. The most common problem with counterfeit or poor QC rod bolts is inadequate or inconsistent hardening, and this is easily identified with excessive bolt stretch.

 

[Tow4]

Replace the rod bolts. You will also need to get the rods resized when you install new rod bolts.