I just started piecing a 3 cyl diesel back together. The main bearings are confusing me. There are 3 that have oil slots and 3 without. Do the unslotted halves go to the bottom or visa versa?
Main bearings
- Thread starter rentthis
- Start date
Hey, RT.........
The slotted main bearing halves should be located in the radius of the Crankshaft Bulkheads (the cast webs that the bearings and crankshaft are bedded into before putting the caps on). The intent is to feed the half that is located within the cap with oil that is delivered through the oil galley (passage) hole that is drilled in the ground radius of each bulkhead, with oil flowing through the slot. If a solid bearing shell were placed in the bulkhead (crank support web), the oil could not flood the bearing because it would be blocking the lube feed hole. Just remember that the caps get solid bearing halves.
The slotted main bearing halves should be located in the radius of the Crankshaft Bulkheads (the cast webs that the bearings and crankshaft are bedded into before putting the caps on). The intent is to feed the half that is located within the cap with oil that is delivered through the oil galley (passage) hole that is drilled in the ground radius of each bulkhead, with oil flowing through the slot. If a solid bearing shell were placed in the bulkhead (crank support web), the oil could not flood the bearing because it would be blocking the lube feed hole. Just remember that the caps get solid bearing halves.
This engine has internal, removable main bearing cases. based on you reply, I'm understanding you to say that the unslotted bearing goes down. Both halves have drilled oil ports.
North Idaho Wolfman
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It's a little bitty Perkins 400 series. The main bearings came as described. The engine has internal bearing carriers. After thinking about nzzshl info, it makes sense. I have spoken to some of my diesel gurus. They all agree with nzzshl. My problem was deciding which was up and which was down in the round carriers. I put them with the oil ports to the slotted halves of the bearings.
North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Normally it is best to keep the oil galley hole in the bearing case / holder lined up with the oil galley port in the bearing.
If there is no physical stops on the bearing holder or bearings, then the bearing most likely has a grove all around it so no matter how you put it in oil will get to the hole and thus get to the crank.
If there is no physical stops on the bearing holder or bearings, then the bearing most likely has a grove all around it so no matter how you put it in oil will get to the hole and thus get to the crank.
I find it strange that this bearing set only has the oil groove in one half of the bearing. I lined it to where all oil ports are aligned with the groove at the top.Thanks for your input. Mike