Engine Bearing Trouble

[Jason84NA2T]

Are you saying the thrust bearing has effectively no thrust surface clearance, so there is zero crankshaft endplay? This is with the main girdle in place and torqued down so the crush of the bearing is not playing a part? How does the bearing fit to the crankshaft when it is not installed in the cradle or girdle?

That's very strange and I have not seen it before, but I will admit I've only ever replaced bearings with Nissan or Clevite 77 STD replacements.

[craZed]

Just go get the needed bearing from nissan. Problem solved.

[Evil Z31]

^^^^Because Nissan doesn't sell oversize bearings.


I got my Clevites from my local shop. $40.

[Jason84NA2T]

Speedtech wrote: The bearings fit between the thrust surfaces on the crank when in their free (uninstalled) state.

My current belief is that the thrust bearings from Federal Mogul are machined with insufficient dimension on the backside of the bearings in the space between the thrust surfaces.

I have ordered bearings from another manufacturer (Toga) to see if the same problem exists. If the problem persists with the Toga set then there is a problem with the block & girdle .... which is highly unlikely as this was a perfectly running motor not long ago. If the problem disappears with the Toga bearings then the problem is with the Federal Mogul bearings.

Where did you order your clevite bearings from?
Yes, I agree the bearings must have been machined incorrectly. There's some perfect use of logic, not something you always see on forums :-)

Isn't another option to take your t-gage and measure the inside distance of the thurst bearing and compare it to the stock one you removed? Then measure the journal width for kickers and you'll find roughly how much side clearance is being lost.

I bought my Clevite bearings from NAPA on a shop acocunt. My local store is attached to the warehouse, so they actually had them in stock.

craZed wrote: Just go get the needed bearing from nissan. Problem solved.

True, as long as the others plastigage out alright then you could just buy a new thrust bearing from nissan and be done with it.

[james]

did the crank get machined correctly ? might pay to check with a dial gauge. One engine shop we used to use couldn't find a 3 thou bend in a crankshaft for my sisters car.

might not be worth checking unless all else fails

[defrag010]

You might try champfering the outside lip of the thrust main bearing housing, because I've seen lips on the outer edge of the bearing housing cause alot of problems during assembly.