2F rebuild help! Main (thrust) bearing size issue (1 Viewer)

[Bluegrass40]

I was assembling my 2F rebuild today using a set of .25mm undersized mains from cevite . I put the bearings in the block and when I lowered the crank in the #3 bearing was tight (would not fit at all). Upon removing the crank I realized the issue was the side walls of the bearing (thrust side) were wider than the journal. Here is a picture of the bearing and the packaging.

When I looked at the box I realized there was little note in it stating that the bearing had a wider width flange.

Looks like this bearing set will not work, or I will have to get my crank ground again on the thrust faces. Anyone run into this before?? Suggestions? @FJ40Jim or anyone else?

I’m assuming that there is not good way of modifying the bearing. I do have access to a cnc and manual mill, surface grinder (which does not seem like a good idea) and most other machine shop equipment.

I’m also assuming that there is no good way to get may hands on just the #3 bearing......

Suggestions appreciated.

Thx!

 

[65swb45]

My fourth machine shop’s learning curve included sending the crank out a second time because it was turned before bearings were in hand.

Do not shave the thrust bearing.

 

[Bluegrass40]

@65swb45 thx for the response! I had a feeling that the only solution was new bearings or a return to the machine shop.

Is it standard for undersized bearings to have the wider thrust face, or is it possible to find a set that would work with my current crank (assuming that it is still stock width between thrust faces)?

I will be measuring the old bearings and the distance between thrust faces on my crankshaft to see if I am still at stock width (it did look like the thrust faces were machined when I looked at the crankshaft journal)

 

[65swb45]

It is possible. The tolerances I have seen over the last four decades vary quite a bit.

When I wore out the thrust on my crank in the Karma Cruiser, everyone seemed to think I would need to either weld my crank or replace it. With diligence I was able to source a set of bearings with enough meat to secure the crank after it was simply turned back to smooth with a wider thrust face.

 

[DougAustinTx]

I have gently sanded the outer faces of the thrust bearing to get correct clearance. I would rather remove meat from the thrust face of the bearing than turn the crank thrust faces. As long as you don't go through the outer tin surface of the bearing it should be fine. This exact issue has been discussed in another thread.

 

[Bluegrass40]

Here is the link to the thread that @DougAustinTx may have been referring to. Surprised I didn’t find it this first few times I searched!!

2F Thrust Bearing Width

 

[Splangy]

I’ve also seen this before. I’ve even seen it from a retailer that sells a crankshaft and bearing kit that is supposed to be ready to bolt up.

Don’t try to sand that much material off the bearing unless you like to hear knocks.

Either have the crank thrust surfaces turned to match the bearing or try to find an oversized bearing set with standard sized thrust measurements. It’s inexpensive to have just the thrust surfaces on the crank turned to the proper size for the bearings.

 

[Bluegrass40]

https://www.mahle-aftermarket.com/m...s-and-literature/engine-bearings/eb-20-18.pdf

Good info for those researching main bearings.

 

[Bluegrass40]

Just found this reference. Looks like the bearing set I purchased has a .15mm oversized flange width.

 

[Bluegrass40]

More info Incase someone is following along or needs the info in the future.

The pn for the clevite bearing with .25mm undersized diameter and stock thrust width is MS-2087 P-.25mm. Thx goes to Shively Speed and Machine in Louisville Ky for the pn. Great guy.


I will be ordering a set....

 

[DougAustinTx]

Good to know that the correct parts are available.