Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec Bearing opinions

These cranks are quite hard, much harder than old school cast cranks with standard nitriding.

I was going to mention it before, but forgot. You will be sanding all day with that setup before you make a serious dent. That polishing info you put up is good, but it isn't for getting out the journals. That is just for very light stuff.
IMO you will spend a lot of time on it, then either give up and have it polished or just run it the way it is.
That's kind of the lead-in to my last post.

I wondered if you could really polish the gouges out of a crank by hand as hard as they are. I guess I'll just have to pull all the caps and take a look.

I don't know a whole lot about bearing dynamics. But I can see two things happening with throwing on a new set of bearings over a grooved crank.

1. The groove traps oil and makes no difference.

2. The groove allows for a release of pressure on that point, creating higher pressure on either side.

Those are my guesses, any advice from the experts?

A rod bearings main purpose of existance is to trap particles and prevent damage to the rod journal. That being said, these bearings have lived their life harshly and it's evident on the crank's rod journals. Unfortunately, just inspecting the crank's main journals involves all new TTY bolts for the block, so regardless, might as well spend the extra $50 and replace the bearings. Judging by the rod journals, I would care to put money on the mains being scored as well. As for regrinding the crank ... if you can feel it with your fingernail, time to machine off .25mm and move up to the next sized bearing ... but that's just my opinion. Remember, you can only do it right once

Yeah, well the polishing with Crocus cloth did nothing for my journals. I dropped off the crank this past week at a local reputable speed shop. They were running a race engine on the dyno as I was leaving and it was like music

Just waiting to hear how much material they removed so I can pick up the correct oversized bearings. In the mean time, with the warmer weather I plan on starting the head porting and injector relocation.

Scott took his back to LQK and exchanged for one with 15000 miles. Paid an extra $100. I'll tear it down tonight to have a look. If this one is scored I'm going to flip.