Crank Bearings Worn--Suggestions?

[JesterTac]

When I replaced my rear main seal I saw that the crank bearings were severely worn--down to the copper or bronze material. Not good! :!:

I didn't do anything about it, but after about a week the rear main started leaking again. I'm guessing this is from crank thrust issues. There must be a bit of play down there.

Should I replace the bearings? My initail thought is that they will also quickly self-destruct like the originals because the crank is walking. I'm also guessing that the crank should be machined. What do you think?

I am planning on upgrading to a 360 in the next year or two, so a rebuild is not what I'm looking for. This Jeep is only driven on some of the weekends and occasionally to work (5 miles).

How tough is it to do this? I've never messed around with a bottom end (on a motor), but I have rebuilt a couple of three-speed manuals, and replaced several head gaskets along with other assorted mechanical work.....I know my way around a toolbox--I've just have'nt ran into this problem before now.

I think my Jeep drives me.................to :razz:

[Rogue Racer]

1) Should the crank be machined? 80% probability, yes. Bearings that are worn that much indicate the crank and bearings are getting together (the oil separation film has been removed). Bearings wear quicker than cranks, but cranks are not impervious.
2) Likely the wear is due to oil starvation of some degree.
3) How tough is it to do? Not hard, just time consuming. The engine will have to be removed, oil pan - harmonic balancer - timing cover - camshaft timing gears and chain, just to get the crankshaft out of the block.
4) The leaking rear seal is likely caused by the slop in the bearings allowing the crank to move around so much the seal cannot keep rubbing against the sealing surface on the crank.

Maybe it's time for the 360 transplant a little sooner than planned.

[JesterTac]

1)
Maybe it's time for the 360 transplant a little sooner than planned.

Thats about what I was thinking. Believe me, I would love to speed up the process but although I don't have a wife, I do have a very jealous wallet. #-o

[caionneach]

Maybe it's time for the 360 transplant a little sooner than planned.

This is basically my situation with a 1982 Cherokee I'm restoring, except that I'm going to replace the 258 and T-5 tranny with an AMC 401 V8 and either a manual or auto overdrive transmission.

I've just begun tearing down the 401, but the 258, in which I have just replaced the rear main seal, shows extreme bearing wear on the rod bearings. Not sure about the main bearings yet. The inside of the engine shows signs of oil starvation and high heat. The engine has about 150K on it.

Kenneth