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Hillmann 
Silver Level
Joined: 02 Jun 2014
Location: Wisconsin
Points: 206
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 Posted: 21 Sep 2022 at 9:01pm |
 steve(ill) wrote:
Polishing the journals will be fine, as long as there are not big groves or spalling... You pick any deposits off the journals ,then polish with emery .... small scratches are not a major problem ....
I would look at the MAINS also ......... cam shaft bearings a brass, not babbit ... you might see that it turns smoothly.
ALso this is a BYPASS FILTER system... and it is SPLASH LUBED.. the cam is hollow and has holes in it that SHOOT oil toward the bottom of pistons and run down the rods.. Not direct oil pressure to the bearings.... and the filter just takes 15% of the total oil flow, filters it, and dumps back to sump..... |
I would prefer not to take the main bearings apart. The crank shaft has no up and down or side to side play(that I can tell) But it does have excessive end play. I am assuming the main bearings are still OK, and the end play was that way when I bought the tractor.
I will have to take a closer look at how the cam shaft is mounted and its bearings.
Can you explain the splash lubed part a bit better? The only splash lubed engines I have first hand experience with small engines where there is a dipper on the connecting rod or the gear for the governor throws oil on everything.
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steve(ill)
Orange Level Access
Joined: 11 Sep 2009
Location: illinois
Points: 77846
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Posted: 21 Sep 2022 at 8:54pm |
also note that the connecting rods dont all go in the same way.. Two face the cam and the other two the opposite way... Bearing on the rod is OFFSET one way to get clearance by the center Main Bearing.
#1 MAIN has a thrust built into the bearing.. You might check END SHAKE of the crank and make sure it is not excessive... suppose to be around .005 inch.
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Like them all, but love the "B"s.
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steve(ill)
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Joined: 11 Sep 2009
Location: illinois
Points: 77846
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Posted: 21 Sep 2022 at 8:52pm |
Polishing the journals will be fine, as long as there are not big groves or spalling... You pick any deposits off the journals ,then polish with emery .... small scratches are not a major problem ....
I would look at the MAINS also ......... cam shaft bearings a brass, not babbit ... you might see that it turns smoothly.
ALso this is a BYPASS FILTER system... and it is SPLASH LUBED.. the cam is hollow and has holes in it that SHOOT oil toward the bottom of pistons and run down the rods.. Not direct oil pressure to the bearings.... and the filter just takes 15% of the total oil flow, filters it, and dumps back to sump.....
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Like them all, but love the "B"s.
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Hillmann
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Joined: 02 Jun 2014
Location: Wisconsin
Points: 206
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Posted: 21 Sep 2022 at 8:43pm |
So now that I know where the metal is coming from, would it do any more damage to the engine to polish out the scratches with some fine emery paper on the crank and slap new bearings in and run it?
I know it wouldn't be the best for the new bearings but I want this tractor up and running NOW and don't want to pull the engine until winter to have the crank ground and replace the oil pump. (it looks like the pump still works as long as I prime it)
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Hillmann
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Joined: 02 Jun 2014
Location: Wisconsin
Points: 206
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Posted: 21 Sep 2022 at 8:33pm |
Alberta Phil wrote:
The bearing shells are usually a steel back lined with babbit. If yours got hot enough, the babbit melted out and that's what is in the pan. Babbit is a soft tin/lead alloy with a relatively low melting point.
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Thank you. That is what I assumed was where the material came from but I couldn't find information online or through the manual saying that the bearings were lined with babbitt so I figured I would ask here where someone would know for sure.
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Alberta Phil
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Joined: 13 Sep 2009
Location: Alberta, Canada
Points: 3652
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Posted: 21 Sep 2022 at 8:29pm |
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The bearing shells are usually a steel back lined with babbit. If yours got hot enough, the babbit melted out and that's what is in the pan. Babbit is a soft tin/lead alloy with a relatively low melting point.
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Hillmann
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Location: Wisconsin
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Posted: 21 Sep 2022 at 8:16pm |
Is there babbitt anywhere in a B engine? Is there aluminum in a B engine?
Is there a facing on the connecting rod bearings? Something has allowed there to be about .060 of play between the crank and connecting rod insert and I am guessing it is whatever the bearing inserts are faced with, but I don't know if they have a facing.
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KMAG
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Joined: 26 May 2020
Location: Elizabethtown,
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Posted: 21 Sep 2022 at 8:12pm |
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Babbit would be bearing material from the crankshaft and/or camshaft. If aluminum, it is from a piston(s).
Either way, it is very bad news for the engine.
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Hillmann
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Location: Wisconsin
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Posted: 21 Sep 2022 at 8:04pm |
I have a 1942 Allis B. That stopped running while cutting hay yesterday.
It looks as though the oil pump stopped working and the connecting rod bearings are destroyed. The bearings probably have .060 of play on the crank shaft.
In the oil pan there was what looked like lots of chunks and blobs of melted lead. I didn't have a magnet to test if it was magnetic out in the field and forgot to bring a piece home to test it so I am not sure it was lead but it sure looked like it.
Is that lead(probably babbitt) the facing from the bearing inserts in the connecting rods? Or is it from somewhere else in the engine?
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