Stray Bearing Shim

D

DBSHELTON

Senior Member
Oh Crap! Cleaning the block gasket surface so I can re-install the pan and I look on the floor under the engine and there is a connecting rod bearing shim lying on the floor!!! It just showed up! Now I have to figure out where it came from! It is .004" thickness and is in perfect shape. I have not done anything with the bearings. WTF!!!
 
Kurt in NJ said:
If it fell out the rod nut should be loose,
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Ditto this. Check the rod nuts. If they are all snug, then my guess is that whoever built your engine let a stray shim fall into the oil pan, and it's been there all along until you dropped the pan to clean it. If you find a loose rod cap, you know where to replace the the shim.
 
All the nuts seem to be tight with cotter pins installed very nicely. I guess I should remove the cotter pins and put a socket on the rod nuts to be sure.
What are the rod nut torque specs?
 
If one fell out check all four rod caps.One more reason why cotterpins were all they had,but not good for this application,they dont hold torque.

35 pounds..I would plastgage and reset all rod bearings
 
katy said:
Perhaps a "friend" put it there to confuse you.
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I know a guy that would do just that! And then sit there and watch you check all your rod clearances.

I can't see a shim just "falling" out. If that is the case, what happens when the engine is running?
 
I would test the rods for loose side to side motion, If they are all the same I wouldn't disturb the rod nuts other than to check for 35# torque, unless it is time to check bearing clearances. That shim could have been stuck on the pan flange or block surface after the last time the bearings were tightened, or as a joke that some people might play.
 
Working on a fiends Model T , the #4 rod cap was not seated but was torqued tight. It had a slight knock. Reset it and lightly tapped all rod caps for the same sound. T runs great.
Good Luck
 
I'd check the tension on all of the big end bolts. Any loose one would be the culprit (if there is one). Once you have done that, try turning the engine over with the crank handle. If a shim has fallen out, that big end would be so tight after tightening it that you would not be able to turn the crank.
 
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