Thread: Rotating assemblie problem

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I have no problems rotating crank pistons until I install number eight piston then in rotation it catches or binds in one spot. I have checked rods bearings crank journal it appears nothing is hitting.

Well first, welcome, as I just joined CHR also. I don't normally assemble my own rotating assembly, but the last time I did, I ended up with about the same problem. Just a different number piston and rod assembly. So off to the machine shop I went, to find out I had an out of round rod cap, caused by me ! ! Not to say that is your problem, but something to consider. I guess when I went to assemble the bearing slightly turned and ...... Well things didn't go well from there.

thanks for the suggestion I did find the problem finally there was a burr on the face of the rod where it contacts the other rod I did some light filing now its smooth as butter

if you have a burr on the side of a rod-most likely you have the rods/caps mixed up and /or some caps backwards--------

Originally Posted by jerry clayton

if you have a burr on the side of a rod-most likely you have the rods/caps mixed up and /or some caps backwards--------

yup on bbc and sbc. rod caps and tang to tang and go to the out side of oil pan rail most rods are number on tang side

On disassembly, I always use a punch to number the caps, on the cap side to front of motor. Makes one less problem on reassembly.

if rods are stock they should be number if billet rods use a etch pen do not stamp them. if rods are just stock use a number stamps you can buy them cheap .if you have better rods they may not be numbered as to fire order they many times have a code number so no need to number them do not punch them with a punch not the way to do it and really piss.s off the guy at the machine shop if they need to be reworked

makes 8 less problems

thanks for the advice I am 90% sure that I had the caps and rods right. I believe I hit the crank with the rod when I set the piston. for the record I am popping my cherry on this engine, my father and I wanted to restore a 80s chevy k20 and never got to because he past away a year ago at 58. so now I have got the truck and have been building it from the ground up. when it came to the engine I was gonna go crate but fuck it I decided wanted to learn how to build an engine so any input is appreciated im sure I will have more questions