Thrust Bearing damage - Why?

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Cudafever said:
Maybe i'm off base here but, you said the Rear Most thrust bearing.........If that's the case then it would NOt be from excessive pressure from the rear of the crank pushing forward.
With that picture i can tell which side is the rear part of the crank.
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in the pic the upper side is the rear thrust surface.

Bewy said:
Only going by the photo, but the journal thrust surface looks rough. Some of the early Chinese cranks had quite roughly finished thrust faces & were wiping out the bearing.
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yes, it is rough - because it´s worn now. the other side is fine, just as it was when it was installed.

Thanks guys for your opinions, will call some machine shops to see if this is repairable - don´t know if this can be welded and ground back to original specs. Otherwise it should get a new crank.....did not have this on my to do list, so it hurts a little.
 
For a crank to turn purple,gold or blue only on the one side of the thrust, there was a forward pressure involved. There is something not right regarding the torque convertor or how it's connected!
damagedthrustbearing-jpg.jpg
 
Max1196 said:
For a crank to turn purple,gold or blue only on the one side of the thrust, there was a forward pressure involved. There is something not right regarding the torque convertor or how it's connected!
View attachment 1715685247
Click to expand...

yep.
Seen that on a deal of mine. Ended up the convertor caused it
LA stroker/727
Was so bad the balancer actually moved in an out if you looked at it closely
 
ok....good to hear. I´ll try tomorrow to find a machine shop for such kind of repair.

I also think that this damage started with a damaged torque converter and got worse over the years (built it in 2012).
 
I have had mine fixed at the machine shop that ground the crank. They may or may not want to do it but can recommend someone to do it. Kim
 
negative feedback from several machine shops....repair work seems not so familiar here. Waiting for some feedback regarding a new crank, balanced to my specs from some U.S. Suppliers.

Some more pics, here´s the damaged thrust bearing side:

20210208_090620.jpg


the good side for comparison:

20210208_090630.jpg




The other bearings / journals look good to me:

20210208_085220.jpg
20210208_090145.jpg


the Crank was already pushed forward so far that the main caps show signs of contact to the crank.....damage could have been much worse if i did not catch it now.

View attachment 1715685948
 
Have you thought about rolling in a new bearing and see how much clearance you have.
I'm going to guess, and say the ruff texture on the crank is no the crank........but bearing material stuck to it.
You may need to remove the crank to clean it off.
Steel crankshaft is way, way stronger then a bearing.

If it was mine i would take it to a crank shop to have the journals polished(including the thrust) throw a set of bearing at it and call it a day.
 
oldkimmer said:
I’d be happy to take that crank off ur hands for the shipping. Kim
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since i´m in Germany i think shipping will be a deal breaker. Maybe it will end as an expensive door stop.

Cudafever said:
Have you thought about rolling in a new bearing and see how much clearance you have.
I'm going to guess, and say the ruff texture on the crank is no the crank........but bearing material stuck to it.
You may need to remove the crank to clean it off.
Steel crankshaft is way, way stronger then a bearing.

If it was mine i would take it to a crank shop to have the journals polished(including the thrust) throw a set of bearing at it and call it a day.
Click to expand...

that´s what i thought first, crank material must be way harder than the bearing, new bearings are already on the way.....but it´s really worn into the cranks thrust surface. I´ve torn it down completely today, will make a better pic later.
 
Cudafever said:
Have you thought about rolling in a new bearing and see how much clearance you have.
I'm going to guess, and say the ruff texture on the crank is no the crank........but bearing material stuck to it.
You may need to remove the crank to clean it off.
Steel crankshaft is way, way stronger then a bearing.

If it was mine i would take it to a crank shop to have the journals polished(including the thrust) throw a set of bearing at it and call it a day.
Click to expand...

Nope, unfortunately not only bearing Material :-(

20210208_201249.jpg
 
yeah, sorry for the bad lighting. My workbench is a mess so this spot is not the best to take photos ;-)
 
I can see scratches, but that wouldn't bother me if the outer surface was smooth.
 
Looking at the brg halves in post 42, I'd say you have more than a thrust issue.
The brgs are wearing on the edges, indicating dirt under the brgs or more likely high spot on the crank journal.
 
thanks, but i think this comes from the axial movement of the crank. the cranks radius was pushed into the bearing, that´s why the (rear)edges are more worn.
 
make sure you get the same bearings when you go back with radius on crank they should be slightly thinner
 
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