The radial grooves to "allow more oil to flow through the thrust bearing" is a misconception.
The grooves allow the ramping of the bearing surface between the grooves.
The ramps are the important thing in thrust bearing load capacity. This allows the oil film to build up and provide a stable oil film.
Also, opening up the bearing clearance toward the maximum spec and then adding a high capacity oil pump to keep the oil pressure up during a rebuild
is a bad idea. You are starting out with the same conditions as worn out bearings. Why would you want to do that if you are rebuilding it! The tight
end of the clearance spec with a standard oil pump gives you the best oil pressure and oil film thickness and film pressure capacity. Oil pressure
only minorly affects the oil film pressure which is what really matters.
Rick M.
> Also the surfaces are ramped so oil film will build up as the crank rotates.
> Lot of tests were conducted on this by main bearing Mfg co as they were
> aware of this problem.I experienced it 4 times back in 1990's and learned a
> lot as well in2000 when we started replacing 20-30 engines a year at our
> shop.
> Crank grinders as a rule do not touch the thrust bearing area as they do
> not have the tooling to do it correctly and polish that surface to a mirror
> like finish.
>
> On Wed, Feb 20, 2019 at 6:19 AM Matt Colie via Gmclist <
>
> > Because I missed a number, I ended up buying several sets of main
> > bearings. (Good story, but you have to buy the beer to hear it.) Two of
> > the sets
> > had the Dick Paterson recommended improved oil groves. One set did not.
> > So, this is something that should be checked at assembly.
> >
> > Matt
> > --
> > Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> > Electronically Controlled Quiet Engine Cooling Fan
> > OE Rear Drum Brakes with Applied Control Arms
> > SE Michigan - Twixt A2 and Detroit
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
--
1974 26' Canyonlands
aka "The General"
Clinton, TN
The grooves allow the ramping of the bearing surface between the grooves.
The ramps are the important thing in thrust bearing load capacity. This allows the oil film to build up and provide a stable oil film.
Also, opening up the bearing clearance toward the maximum spec and then adding a high capacity oil pump to keep the oil pressure up during a rebuild
is a bad idea. You are starting out with the same conditions as worn out bearings. Why would you want to do that if you are rebuilding it! The tight
end of the clearance spec with a standard oil pump gives you the best oil pressure and oil film thickness and film pressure capacity. Oil pressure
only minorly affects the oil film pressure which is what really matters.
Rick M.
> Also the surfaces are ramped so oil film will build up as the crank rotates.
> Lot of tests were conducted on this by main bearing Mfg co as they were
> aware of this problem.I experienced it 4 times back in 1990's and learned a
> lot as well in2000 when we started replacing 20-30 engines a year at our
> shop.
> Crank grinders as a rule do not touch the thrust bearing area as they do
> not have the tooling to do it correctly and polish that surface to a mirror
> like finish.
>
> On Wed, Feb 20, 2019 at 6:19 AM Matt Colie via Gmclist <
>
> > Because I missed a number, I ended up buying several sets of main
> > bearings. (Good story, but you have to buy the beer to hear it.) Two of
> > the sets
> > had the Dick Paterson recommended improved oil groves. One set did not.
> > So, this is something that should be checked at assembly.
> >
> > Matt
> > --
> > Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> > Electronically Controlled Quiet Engine Cooling Fan
> > OE Rear Drum Brakes with Applied Control Arms
> > SE Michigan - Twixt A2 and Detroit
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
--
1974 26' Canyonlands
aka "The General"
Clinton, TN
