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Fail mode?

tim2542

Well Known Member
Can anyone tell me the fail mode seen in this bearing? This is a friends 0-200A Continental, relatively low hours on field overhaul. The pic is the #2 bearing, #3 looks similar but better, #1 looks relatively normal with a little debris damage, nothing serious. The engine was disassembled looking for a low oil pressure issue. Pretty sure this is it, but this damage does not look like lack of oil pressure or debris damage. I?m only guessing but it looks like corrosion or some kind of plating failure. The tin babbit is all gone on this one, and much of the copper. The crank looks decent, probably will clean up with polish only. Information from the previous overhaul is sketchy, not even sure the bearings were replaced.

http://i1380.photobucket.com/albums...-85F8-489B-BEFC-8257A37ACA58_zpsgwyt9spe.jpeg
 
By the looks and the description I would check the case halves for alignment of the bearing bores. sounds like there is case distortion or the crank is bent. That bearing got hot.

Does your friend cut the oil filter open every oil change? Did he do it for a period of time after the field overhaul?

Anyway, I would ship the cases off and the crank to be checked and reworked.
 
Wish I could help, but never have seen one like that. Definately seems not to be caused by debris or contact with the crank. I can't imagine what would cause coppoer to break off like that. Copper doesn't really corrode agressively in this environment and I wouldn't expect heat damage to look like that. Copper is very effective in heat transfer and it would take a LOT of heat to break it down and I would expect smearing and deformation, not the pitting/breaking off shown here.

My best guess would be a defect in manufacturing of the bearing, but that is purely a guess. If you can't identify the cause, I am with the previous poster that a check of the crank and case is in order to be safe.

Larry
 
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Please

inspect the bearing and determine the manufacturer. Options are Continental, Superior or Fresno Airparts. If this is what I think it is we can tell you exactly what happened.
 
Which prop did he have on that engine?

There have been issues with the Sensenich Ground Adjustable Prop being so stiff that magnetos won't make 40 hours on the O-200.
 
I am with Larry on this one.
Never seen it just wipe off the overlay like that without further damage.
Hopefully BillL will be along as this is his specialty.
 
Hello
I assume the crank was reground? I would check the surface finish on each journal, I suspect the damaged shells location are the roughest?....
 
Bearing Damage

Have seen bearings with that type of damage due to corrosion from moisture. As far as case problems, that can be told by main bearing wear. It will show up on one bearing half and not on the other or at the same point on both where they separate and 180 from that have none. that shows a warped case. They will run like that for hours with the original bearings in them but put new ones in and have seen a crank break on diesel truck engines. That is the first thing to look for when considering line boring a case or block.
 
Arrgggh

Have seen bearings with that type of damage due to corrosion from moisture. . . .

Agree . . My gut was corrosion, but moisture is right there. Sulfur in the fuel and blow-by will acidify the moisture in the oil. Another contributor is overdue oil changes and allowing TBN (ability to neutralize acids) to fall out of usefulness. The PbSn overlay is completely gone, (dissolved) this is possibly the worst bearing I have ever seen.

Confirmation would be how the remainder of the innards of the engine look. Cylinder walls, cam, and lifters.
 
I have seen this in marine engines, high moisture content in oil along with acid build up, leaving contaminated oil in for a long time with engine stored.
 
This is an east coast friend and me on the west coast so I?m just looking at pics also. But to answer a few questions the crank was yellow tagged but don?t know if it?s std or not.
Further info now the bearing tang slots in the case are worn and the bearing has moved longitudinally enough to almost completely cover the oil port, yet it doesn?t look like oil starvation. The bearing can?t move if the case is torqued up proper and the case is machined correctly. So everything will go in for yellow tag and reassemble with new bearings etc.
Thanks! Tim
 
Rebuilder did not completely remove the cosmoline from new bearings, resulting in high initial friction and heat? Rebuilder used old surplus bearings that had surface corrosion? Dirty/plugged journal feed to this bearing at overhaul? Failed to apply overhaul (thick) lubricate to this bearing at overhaul? Installed a 0.003" over bearing in a standard journal? Moisture and acid damage will generally be prevalent throughout, very noticeable in valve covers as rust and green slime....your block looks clean, free of moisture and acid. Good luck!
 
Bearings

Don't know where you have seen cosmoline on bearings they come with nothing on them. Various things can be used to coat them before installing the crank or cam. Some use oil or bearing lube not wheel bearing type of grease. If the bearing had been hot it is not showing that along with the face it would be moving metal off of the bearing onto the crank. Its corrosion nothing more. And when installing bearings you never touch the surface with your bare skin as that will cause problems due to the acid and moisture on your fingers. After installing hundreds of bearings over my life of doing engine work have again never seen a bearing coated with anything had I it would have been in the garbage.
 
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OP

has not identified the make of bearing. To cut the story short: Fresno Airparts had bearings made, who knows where, and sold them as "new old stock" for Continentals. This is the failure mode that those bearings suffered from.

If it was caused by contaminated oil then all of the bearings would probably have suffered the same. OP said they did not suffer the same.

Another clue is the bearing tab not allowing the bearing to sit in the proper position in the case.

OP stated that this was a field overhaul. If cost was a factor, the Fresno bearings were half the cost of OEM.

I would bet a great deal that this is not a Continental bearing.
 
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