A rod bearings and other questions

Mike(NEOhio)

Well-known Member
Location
Newbury, Ohio
The rods seemed a bit loose so while doing other repairs I pulled the pistons. The crank journals miked 2.9985-2.9990 and very clean all around. I didn't have much luck with plastigage but checking the bores I got 3.000 to 3.003 and one had a scored line in the babbitt but there was no corresponding line on the journal and the shim packs were intact. This thing is in great shape. Belonged to my FIL but he was the third owner. He took good care and used UNICO oil, changed twice a year and never sat in the weather. The mains are a bit loose and I'll get to those in warmer weather.
A couple of questions:

I don't think it will need rings. Is it OK to move the rings around to stagger the gaps or should I leave them as they came out? Do they rotate around in the grooves or remail sationary.

The shim packs have one steel .062 and one brass .032 and six .003 brass in between. Does it matter which outer shim goes toward the cap?
 
The only 2cyl crankshaft problem I've ever had was due to a faulty auto gas shut off, the bearings seem way over designed.
I normally put the shims back exactly the way they were. Have you measured the cylinder bores or looked for a ridge near the head end? It seems unusual to go to all that work and not do a hone at least and new rings.
 
I have seen A crank shaft ruined running with broken oil pump coupling. Rings turn when running just as tappets, push rods and valves even without rotors and freefloating wrist pins.
 
For the rings they should be free in the grooves and able to rotate on the piston. If not they rings/grooves need cleaned up. You can try to offset them when you put them back in, but things will move to where they want to live when it runs anyway.

When you put the rods back in use those 0.003 shims to set your clearance (sounds like you might be close with your measurements). Remove one 0.003 shim on each side of the rod, install and tighten the rod bolts. Check the rotation of the crank, if the bearing binds or provides any resistance at all, disassemble and reinstall the shims you just took out and put it back together. If the crank rotates freely, remove another set of shims until it does drag. Repeat as needed. Then do the other rod. No measurement tools required. It shouldn't matter what order they are in, as long as long as the shims match on each side of either given rod (top and bottom of 1 should match, top and bottom of 2 should match, 1 and 2 don't need to have to match each other.
 
(quoted from post at 14:54:09 01/25/23) For the rings they should be free in the grooves and able to rotate on the piston. If not they rings/grooves need cleaned up. You can try to offset them when you put them back in, but things will move to where they want to live when it runs anyway.

When you put the rods back in use those 0.003 shims to set your clearance (sounds like you might be close with your measurements). Remove one 0.003 shim on each side of the rod, install and tighten the rod bolts. Check the rotation of the crank, if the bearing binds or provides any resistance at all, disassemble and reinstall the shims you just took out and put it back together. If the crank rotates freely, remove another set of shims until it does drag. Repeat as needed. Then do the other rod. No measurement tools required. It shouldn't matter what order they are in, as long as long as the shims match on each side of either given rod (top and bottom of 1 should match, top and bottom of 2 should match, 1 and 2 don't need to have to match each other.

If you were to adjust the gap, make sure ypu have the minimum gap measured with plastigage. Otherwise you loose the oil film. I learned that the hard way, but was able to polish the crank and move on....
 

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