Play in rods on SH

Anonymous-0

Well-known Member
I put the flywheel on the SH engine last night and noticed a small amount of play when turning it back and forth. What I was feeling was the clearance between the crank journals and rod bearings. I then reached under and grabbed the rods and could feel a slight movement in each when I wiggled it laterally. Some history, the engine ran fine before the rebuild with good oil pressure. I took the crank to my machinist, it had .010” bearings from a previous rebuild. The journals were nice and clean and round and he recommended new .010” under bearings and nothing else. I used Plastigage at assembly and all four rods were right at the outside edge but in spec. I’ve done 9 previous Farmall rebuilds and never had a problem but I’ve never noticed this kind of
“play”. Could just be that I never noticed it before. Any comments on what I should do before I install the motor? I’d like to think that I’m just feeling the .0035 clearance, all four rods feel virtually the same. Comments??
 
Hmmmmm, something's wrong.

Really doubt if you could feel three and a half thousandths oil gap laterial movement. Especially so, if you used an assembly lube of some sort.

I'd be for rechecking those rascals to make sure they gave you the right inserts. It almost sounds like you've got the standard sized inserts to be able to "feel" any laterial movement.

Very hard for human "perception" to pick up anything smaller than about .010".

Allan
 
Lateral means side to side, what you are feeling is the rod end clearance. Push the rod to one side and then using a feeler gauge measure the gap between the side of the rod and the crank, spec. is 8 to 12 thousandths. Since you used plastigauge on all the rod bearings then it should be fine.
 
zLets get this straight. Do you mean movement parallel to the crank, or perpendicular?

Gordo
 
Pull those inserts and have them measured. The bearing books should show the specs for maximum wall thickness at crown. Better now than when it may be too late.
 
90 degrees to the crank. The Plastigage showed within spec at the center of the rod cap. I suspect I need to have the rods reconditioned. The only thing I can think of is that the rod with cap on is egg shaped.
 

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