Packard Forum Index » Post-War (1946-54)

coal oil = Kerosene = lamp oil.

First things first. plastigauge the rods. we want to determine the source of the knock. Had it never knocked we wouldn't have gone this far yet.

Check that UPPER rod bearing to see if it has spun too or if it is locked in good. Very important.

I like to jack the crank on both sides of the main (or near ends of crank) that i am plastigauging. It pushes crank up against ALL of the upper bearings. So clearence is measured at the bottom.

Gotcha. And i have both the upper and lower halves of that rod bearing out, both sides are beat up and scored. I'm glad that the other ones look so good, but i wonder why this one bit the dust. I believe it is the source of the knocking for sure, a lot of the metal is missing off of it in some places (sharp edges, locator "tang" missing)

oh. ok. So the only disassembly u've done is ONE MAIN bearing cap???? Just make sure to check the upper main bearing shell to see if it is locked into the notch in the block. If it's not locked in it should move pretty easy.

And to plastiauge the rod do you have to do anything special?

I've always done this on the engine stand, i don't recall doing anything special, but then again, i've always been working on random GM v8s, etc.

Locator tang missing from BOTH upper AND lower?????

Need to check crank and maybe bock oil gallery to be sure they are clear of debris. pump some air pressure or oil or something thru it. Gotta make sure oil is getting the bearings.

Plastigauging mains on an engine stand is differnt because the engine is upside down when plastigauging. When plastigauging rods just be sure the upper rod and piston assembly is down against the crank all of the way anmd plastigauge on the CAP bearing. Make sure that the crank does not turn any at all.

"oh. ok. So the only disassembly u've done is ONE MAIN bearing cap???? Just make sure to check the upper main bearing shell to see if it is locked into the notch in the block. If it's not locked in it should move pretty easy."

Taken 2 whole rods apart (4 bearing shells)...the beat up one and one good one to get some numbers off of.

One main cap down but only the cap bearing half out, the upper part of that main bearing is still locked up in there pretty good.

After getting the rod back on the motor with the upper shell, i'll put air pressure to the spark plug hole to be sure that the rod is seated on the crank, then plastigauge it. That should handle the 2 rods reinstallation.

I may do a third rod to see if i can read the size better.

What to do with the main that had the shimming, well, i'm not sure yet.