Camshaft bearings improper or installed wrong?

[jerry598]

Just got my 929 bare block shipped back from the machine shop (magnafluxed and full-torque L&S inserts installed in those 6 inner-outer main bolt holes.

Had them install new camshaft bearings also, but wonder now if that was a mistake and a waste of money since the old bearings were in good shape.

When I first took the camshaft out during disassembly, I only made a mental note that each of the cam bearings seemed to have at least one very large oil feed hole in them, and I'm not sure now which way the oil holes were oriented.

The new bearings have only one small hole in them at the 6:00 oclock position, except for the #1 bearing which also has a hole at the 2:00 oclock position. The holes definitely seem smaller than the holes in the old bearings, which are now in the shop's scrap heap.

In the new bearings, the 6:00 oclock holes in the first 4 bearings go directly through to the main crank bearing. The #5 bearing hole is also at 6:00 oclock, but there is no corresponding passage going down to the crankshaft.

Are these bearings installed properly? I can't find any technical information on the subject.

I've got a few other questions about the machine shop work too, but don't want to clutter up this post with them yet. Thanks for any reply.

[jerry598]

Looked up a photo of the bearings for my '95 6.5 in the Rockauto catalog. The bearings in my block match the bearings in the catalog photo. So........they might be the right ones.

I just can't see how the oil is fed into the bearings without a hole coming in from the oil gallery, which the front cam bearing does have at the 2:00 oclock position, but the rest of them do not. It just bugs me when I can't understand how something works. All I can figure is that the oil comes from the lifters or thereabouts and simply splashes onto them enough to lube them properly.

[DmaxMaverick]

There should be a relief channel on the bearing outer surface. The holes don't have to be lined up. While there could a lubrication efficiency gain with the holes lined up, there's no proof of it I've ever seen. The bearings aren't dynamically lubed, and if too much oil passed them, other downstream components would be starved. Cam bearings can walk around over time, so if the holes being lined up were critical, we'd see a bunch more boat anchors out there.

[jerry598]

Thanks. I think I get it now. Also found one other post by Robyn where she describes an annulus groove (probably the same thing as your relief channel) behind each cam bearing that flows oil from the oil gallery. Oil must flow around the bearing through that groove to the feed hole at the 6:00 oclock position and then also down to the the main crank bearings through that passageway.