rebuild or replace engine?

[since95]

Originally Posted by gabedrummin

If I might ask a question about re-building these engines. I was told that the cranks are reused and polished and run standard bearings . I have an engine that has low oil pressure at idle when motor is at operational temp.If I run the motor hard and come to a stop it will trigger a low oil pressure warning light while stopped till I drive again.Once idle come up light goes out.I did the oil pressure bypass update. And this did nothing for the problem. So the problem must be to much clearance between the bearings and crank journals.So the polishing of the stock crank will remove at least .0005 a half thou to a thou .001 so any rebuilt motor will have a low oil pressure a lot sooner than a motor with a new crank. Can the crank be welded and ground to stock dims.

So are you saying you have a used or polished crank in your car? I tried to read up on what I could do to salvage my crank, and what I found was only a few people had luck welding and re-grinding, or plating and regrinding. At this point my thought is a good used crank that I was told was checked and polished was better option.

I just measured all my rod journals this morning with calipers (not perfect, but my micrometers are at work) to see if anything happened to the burnt journal, and all six measured exactly 52.98mm. I will measure both the original crank - main and rod journals, and the polished one I receive and post the results. I will then polish my original crank to see how much they change - plus I can see it becoming some form of furniture like an end table, so shiny journals will look better .

[gabedrummin]

From what I know my motors inside is stock with 125k miles on it. The question is how long before a crank that is polished will start to have oil pressure issues. I cant understand why no one makes bearings that allow you to grind of .010 to fix any problems , If you look at the surface were the bearing spun under a microscope you will see a very bad surface, It is actually peaks any valleys ,to get it polished removes all this .In the process it reduces the pin diameter.This will at some point have an effect on oil pressure. What is the tolerance on main and rod pin diameters?