machining/undersizing crankshaft...good or bad idea?

[lil4x4dsm]

Hey guys, well last I posted I was trying to diagnose a knock in the bottom end, I believe I found the problem. My oilpan was dented into my oil pickup, you can see where the screen actually rubbed against the botom of the pan. Bad news!!!!! I pulled the motor and completly tore it down and today I pulled the rod and crank bearings out one at a time to see if they had suffered from any oil starvation. #1 and #3 showed some scoring and heat build-up #2 had some scoring you could almost feel with your fingernail,#4 looked good. Crank bearings looked good except for the rear girdle bearing that had a nice big score in it you could easily feel in the bearing, but crank appeared to have little damage that I could feel. Since i have it this far apart I want to replace the bearings and I need to know if micropolishing would be enough or would i actually have to turn/undersize journals? Also any idea as to how much micropolishing removes? It says in the shop manual that the crank has a "special surface treatment" and not to machine the crank. I know people have used undersized bearings, but what kind of luck do they have, and how crucial is that "surface treatment". This was supposed to be a simple clutch and flywheel replacement that has gone horribly wrong!!! It has now turned into a engine rebuild, and I need to get cracking, I borrowed a car for my "2-3 day clutch job" that has turned into a two week ordeal already

Thanks for the help
Greg

 

[Defiant]

Your machinist will know better than any of the rest of us. Polishing cranks is routine.

 

[gen1runner]

From my own experience I've never had any problem with my crank, i got it from slowboy im pretty sure the journals were turned down .025, the quality of the journals was great, perfect finish, but yes as defiant said check with a good machinist in your area about it, they would be able to tell by looking at it whether or not it needs to be turned down or polished.