big cam cummins main bearings

dieseldoc

Member
how do you guys roll in main bearings on the old big cams and deal with the wedding bands. had a pretty good conversation with a guy today and it seems he thinks i have been doing them wrong all along. thanks
 
Hello dieseldoc,

I usually get them started with a home made flat piece of stainless. Then finish them the rest with a bolt in the oil hole. I use the bolt to roll them in. Too much binding either way,in or out, is not a good thing.

Guido.
 
Two things I learned years ago were to loosen all the fan belts on the crank and to use the biggest brass brake shoe rivet you could in an oil journal hole. The rivet being brass, if it got cut off didn't scar the crank. Also used a thin,flexible putty knife to roll in the ones that didn't have an oil hole in the journal. I don't put any grease on them either as the bottom ones with the grease'll transfer enough while turning it to lube the top ones.
 
The NH and NT series Cummins up to and including the N14 as you know use the dowel ring or "wedding band" as the anti rotation device instead of the more usual tangs in the bearing shell. The correct procedure is to roll in the upper shell which will need to be rolled in with no lube on the bearing. Align the cut out in the shell with the counterbore in the block, then place the wedding band in the counterbore being careful to make sure it is seated in the bearing and block. Lube the lower shell and place in position, also being sure to align the cut out to the wedding band, then install cap, torque to spec, loosen bolts (leave cap in place) and torque to spec again.
 
Just curious dieseldoc, how does he do it? It would seem that any other way and you run a big risk of not getting the dowel ring and bearing inserts aligned.
 
he says he rolls the upper bearing in and then puts the lower bearing on the cap. sticks the bolts thru the cap with the ring over the bolt. I dont see how that could possibly work.
 
I agree Doc, awfully risky as he has no way of knowing if the lower shell is positioned properly in the ring, or the ring in the counterbore. For what its worth the N14 service manual says to do it our way.
 
Hello dieseldoc,

If he does it that way, it is wrong! HE has been lucky. The ring should go in before the cap, NOT with the cap! Many times the upper shell is NOT aligned with the ring, as you know....

Guido.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top