Topic: can someone salvage by resurfacing crank bearing shells

[BomberMann650]

Will start by admitting that I don't know the limitations of film coatings on crank bearings.
It is a frustrating to search for 47 year old parts for a total engine overbaul.
Whats an engine builder to do?  Especially in the future when NOS parts are truly NLA?

Can a coatings company fill a proverbial void on critical engine parts that sat for decades in apparently acidified oil?
Do we have the technology to restore functionality to antique parts?

[pjlogue]

I looked into this idea when I realized the crank bearings for old GL1000's were no longer to be found.  I read up on main bearings and was amazed at how much goes into them.  There are 3, sometimes 4 layers that make up the main bearings and each layer has a very specific purpose, depending on the application, loads, engine speeds...etc.  Each of the intermediate layers has a specific thickness and alloy make up.

Main bearings start out as flat sheets where the layers are deposited and then cut, stamped, machined.  I think rebuilding the bearings is possible but would be very expensive.  I did find a company that does do this rebuilding and tried contacting them but never heard back.  I think they were in India.

I would think that deposition of the "Babbett" layer would be possible as long as the sub layers were not worn into.  Honing the newly deposited layer to exacting tolerances would be another matter.  I used to think these bearings were just stamped steel of some alloy.  When I started looking into it, it was a real wake up.  The "Babbett" layer is a mix of zinc, tin, antimony and other metals that impart specific qualities to the bearing surface.  The layer is intentionally soft to allow for imbedding of dirt/contaminants.  This helps prevent damage to the journals which are hardened steel alloy.  The intermediate layer (Copper alloy) is used to support the Babbett layer, bond the Babbett layer to the shell and act as a cushion for the Babbett layer.

I will see if I can find the web site where I found this information and the company I tried to contact.  It will take some digging.

Since these engines are low output, I would think it would be possible to re-deposit a new "Babbett" layer and have fairly good results in longevity of the engine. (i.e., the thickness and make up of the alloy would not be super critical)   Finding a company that does this would be difficult.  Another alternative would be having a critical mass of people willing to buy newly made bearings so that a manufacture would be willing to make them at reasonable cost.

-P.   

[newday777]

That is some interesting information P and a good subject to BomberMann650

[pjlogue]

I found the link I posted on NGW a while back.  https://rebabbittingbearing.com/babbitt-bearing-repair.html  As I said, I never heard back from them. 

If anyone has luck in finding a company that does this type of work we all would appreciate a post about it.  I have a spare GL1000 engine I intend to rebuild once my shop is finished and will eventually rebuild my '76 750 engine.  I don't know the state of the main bearings in either engine but having a source of main bearings would be reassuring before I tear them down.

-P.

[MauiK3]

There are really no main bearings available for early Gold Wings?
Shame on Honda.

[bryanj]

I have heard but not looked myself that a mitsubishi main shell can fit the GL 1000 and even allow a small undersize

[BomberMann650]

So bearings are a laminar assembly, neato!

I was just staring at my shells thinking.  If there was a product that could adhere to, and self level, on these ol parts.  That product would sell.  Then i saw a cerakote advertisement.

People are claiming to put that sh// on anything that moves.  But no word on longevity.

[enwri]

Surely, somewhere on this site there will be something, just have to work out where to look.

 https://web.tecalliance.net/mahle-catalog/en/home

There's a menu on that page -"Search by brands and product groups" That has a "big end bearing" section. As well as crankshaft bearings and other bits.
Then a confusing set of parameters to search on the right. Case size, shaft size, clearances, width.

Somewhere in there is a set of undersize/oversize? bearing shells from some VW 1300 triple that should work for a Yamaha TDM850 twin.

[pjlogue]

I have though about the possibility of electroplating a new coating on the bearing inside.  I do not know much about electroplating alloys.  I know it is possible but would the deposited coating have the same % make up as the material you started out with?  If the concoction in the electrolyte, i.e. percentage of components in the electrolyte would plate on at the same percentage then I would think replating the inside of these bearings would be fairly simple and would be quite controllable as far as thickness.

Anybody have any experience electroplating alloys?

Edit:  Just found this.  http://substech.com/dokuwiki/doku.php?id=electroplating_alloys  I'll have to read and think about this a bit. 

-P.

[Don R]

 Yamiya.   It appears $120 would buy a full set, of course plus shipping but well worth the peace of mind knowing what you have. A couple cb750 guys I know when in doubt always just buy green and call it good. A mini sprint racer I met ran 1,000 cc motors at crazy rpm and never bought any new bearings.  https://www.yamiya750.com/index.php?main_page=index&cPath=246_21_250_155

[Tracksnblades1]

I looked into this idea when I realized the crank bearings for old GL1000's were no longer to be found.  I read up on main bearings and was amazed at how much goes into them.  There are 3, sometimes 4 layers that make up the main bearings and each layer has a very specific purpose, depending on the application, loads, engine speeds...etc.  Each of the intermediate layers has a specific thickness and alloy make up.

Main bearings start out as flat sheets where the layers are deposited and then cut, stamped, machined.  I think rebuilding the bearings is possible but would be very expensive.  I did find a company that does do this rebuilding and tried contacting them but never heard back.  I think they were in India.

I would think that deposition of the "Babbett" layer would be possible as long as the sub layers were not worn into.  Honing the newly deposited layer to exacting tolerances would be another matter.  I used to think these bearings were just stamped steel of some alloy.  When I started looking into it, it was a real wake up.  The "Babbett" layer is a mix of zinc, tin, antimony and other metals that impart specific qualities to the bearing surface.  The layer is intentionally soft to allow for imbedding of dirt/contaminants.  This helps prevent damage to the journals which are hardened steel alloy.  The intermediate layer (Copper alloy) is used to support the Babbett layer, bond the Babbett layer to the shell and act as a cushion for the Babbett layer.

I will see if I can find the web site where I found this information and the company I tried to contact.  It will take some digging.

Since these engines are low output, I would think it would be possible to re-deposit a new "Babbett" layer and have fairly good results in longevity of the engine. (i.e., the thickness and make up of the alloy would not be super critical)   Finding a company that does this would be difficult.  Another alternative would be having a critical mass of people willing to buy newly made bearings so that a manufacture would be willing to make them at reasonable cost.

-P.   

+1

Back when I couldn’t grow whiskers, I pulled wrenches for the local Chevrolet Mechanic..
We used Delco Moraine 400 bearing, a heavy duty hard bearing for severe duty,  perhap one of the granddaddies of the good tri-metals. You were not allowed to touch that micro thin spayed on break-in coating…

Later working partime for a local garage,minutes away from the college I was attending, the owner insisted you polish the same with a shop rag until the aluminum shined like a mirror.  I obtained similar printed data about,as you posted,  the millions of dollars in development and research as well as the individual layers and their intended purposes. After proudly presenting the document, detailing the construction, research, and technology as proof we shouldn’t be rag polishing the bearing. After a careful read he merely replied, “we polish them here…”

Rarely either garage had callbacks.

No I still won’t polish a bearing…