Main Bearing

[Shade_Tree]

Need some help please!

I have a 4.2l crank with 3727 casting.

I am having trouble with the 7th main bearing. 1 thru 6 are fine but the 7th rear main bearing lip is too wide for the crankshaft. Between the rear main seal and rear main bearing there is a lip that goes between them on the crank.

The lips are so wide it would require a lot of shaving to make it fit and that cannot be right.

The bearings are for the 4.0L they are Sealed Power 7211 M40.

20130921_121345.jpg

[Shade_Tree]

I just verified the Sealed Power PN 7211M is for the Jeep 4.0 the 40 at the end of mine is for undersizing since the crank is ground.

[SilverXJ]

That is the thrust bearing. It goes on the #3 position. Not a Chevy.

[Shade_Tree]

Silver, ...oops thanks....

[SilverXJ]

Common mistake. I've seen it happen on other engines to where some have gotten so far as to have the main caps bolted down then wonder why the crankshaft won't rotate.

[Shade_Tree]

I owe you a beer anyhow! I got all the caps down, working my way from the middle out stepping up the torque, rotating the crank and then stepping up the thrust bearing. I have now found that I have 0.015" play where the manual calls out 0.0015 - 0.0065" play. I didn't "tinker" with the bearings...I need to find a shim kit.

[SilverXJ]

That is a lot of play. I don't think there is a shim kit for the thrust bearing and I also haven't found a thicker bearing either. You might need to talk to whom ever the crankshaft came from.

[Shade_Tree]

Uh-oh...it was purchased from Advance Autoparts. The crank had 0.040" ground off the mains...do you think they went too far and that has something to do with this?

I have clearly found this is not good, but haven't been able to find a solution.

[SilverXJ]

The mains don't concern me as much as the .015" end play.

[Shade_Tree]

Gotcha, I was making a mental connection that the amount ground off has altered the way the crank sets...causing that amount of end play. Thoughts?

[SilverXJ]

The .040" of the crank journals should not have effected the thrust surface. Typically the grinder will just be touched to the thrust surfaces to clean them up slightly. In your case the thrust probably had severe wear and they had to do more than just touch it a bit to get it to clean up.

[Shade_Tree]

That is certainly how it seems at this point. I removed it last night and took it to Advance for replacement, hopefully I'll hear something on that today.

Now I need to find the specifications for the crank so I can take a caliper with me when I pick up, try at least to prevent picking up another bad part.

[SilverXJ]

The FSM gives 1.271 to 1.273 in for the #3 journal width. I would also measure the bearing, thrust face to thrust face, with the main cap installed and compare to what you are getting.

[Shade_Tree]

Well, Advance was great about giving my a refund...but they have my core.

Does anybody have a crank for sale? ...I have a nice set of 0.040" over Sealed Power bearings to trade....