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Rod & Main bearings, plus other questions.


Probationary Member
Aug 6, 2003
Hey there guys,

I'm about to try and ressurect my engine form the dead here.
waaaaaaaay back I spun a rod bearing (and turns out mains too) but being stupid and looking for a quick fix, I only changed hte rod bearings without checking the crankshaft properly.

Now, the car started after that. and sounded good. but there was a hollow knocking sound. I had to give it up for awhile after that since I moved away and couldn't work on the car again until now.

I have the engine completely out now, and upside down, with the crankshaft out as well as all of the bearings. Now that I can see properly, the main bearings looked pretty bad, as well as the crankshaft itself. Infact, the newer rod bearings I'd put in were already showing wear.

SO here I sit, with a new crankshaft and new sets of rod and main bearings, and this time I want to do the job right. ofcourse I have concerns now.

First of all. what is the proper way to lubricate the bearings, and do I lubricate both sides, or just the side that touches the crankshaft. Also, is oil the proper lube, or is there something else more specific I should use.

Second question, kind of the scary one. that hollow knocking really freaked me out. I'm really hoping that it was just the main bearings that were shot causing it. But they didn't look as bad as the rod bearings so I'm worried it's something more.
I did notice that the pistons had some back and fourth play, (not much) when I move the rods, is this normal?

I know this is vague, but if anyone can lend me some info it would be greatly appreciated, if you need anymore info I'll try my best.

Thanks a lot.


DSM Wiseman
Jan 17, 2004
Chesterfield, Virginia
Before you put it back together, take all 4 rods to a machine shop and have them check the big end for roundness. If it spun a bearing before, chances are that rod needs to be reconditioned. If you try to put it back together with a rod that is out of round, you will be redoing it very soon.

Now, lube only the surface that touches the crank. Make sure the back side of the bearings are dry and clean. Also do the same with the main saddles, main caps, rods, and rod caps. I stress the clean part. A little oil on the backside of the bearing wont affect anything.

As far as lube, find a good quality assembly lube. Some lubes are just a extreme pressure lube where others are a moly lube. Both will work fine but if the moly lube is used, make sure you do an oil change after about 15 minutes run time on the new engine. The moly will clog the oil filter and cause all of the oil to bypass and not get filtered at all. Even if just an ep lube is used, its still a good idea to change the oil after the engine has been run at operating temp for a few minutes.
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