Main Bearing Case Side Marks

[sdcassel]

I am a little rusty searching this forum, so this may have already been addressed somewhere. I am reassembling a D950 from a B7200HST, and the service manual says "install the main bearing case with their side marks toward the flywheel." And then "Be sure to install main bearing 1 with its oil groove facing outward.' My mechanic friend and I cannot for the life of us figure out either of these steps; there is only one way to install the rear main bearing case, and that puts any "side marks" there may be facing away from the flywheel. And what is the "oil groove" on main bearing 1, and which direction is outward?

 

[Mark15]

Looking at my WSM for the B20, which also has a D950.

Could you be confusing the "Bearing Case Cover" which is bolted to the back of the engine (just under the flywheel), with the "Main Bearing Case Assembly" which are located along the crank, which have two halves and clamp to the crank? Those slide into the engine with the crank.

The latter look like they could be reversed, and I see the comment you mention in my manual as well to face the marks toward the flywheel.

The "Bearing Case Cover" can only face one way like you say, but it only has a comment to rotate the Top Mark to the top when bolting it back onto the engine.

 

[sdcassel]

Actually, I think I've got it! First, I believe the side marks are the casting marks? They are on the opposite side of stamped numbers the match the split case correctly. And that is the way it works for the rear bearing case to have the mounting holes for the end flange facing the flywheel.
And it's easy to tell which bearing case (of the other two) is forward and which is aft; the oil passages are slightly smaller for the forward case, and match the one in the block (not sure why there are two in the case and only one in the block, though). And the oil grooves to which it is referring are on the side (thrust) metal for the rear bearing case; there are two pieces for each side (forward and aft), each has a tang, so orientation is easy; the other side has an indent (oil groove) in the middle; they should be place where they will be away (out) from the bearing case. These are only on the rear (closest to the flywheel) bearing case, and hold the crankshaft from moving axially. Whew! That's not exactly clear in the shop manual!