crankshaft bearings

[Roger in Manitoba]

After pulling the oil pan off to get at the oil pump, I decided to pull the bearing caps off to check the bearings. They all look good except #4 connecting rod bearing. It's completely shot. The mains look good too.

On 1-3, on the back of the bearings, it's stamped ".020" Does this mean that it's already .020 under? On #4, it doesn't have these markings. Almost make me think that #4 didn't have the correct bearing installed.

Part of the bearing failure may also be due to a possible oil passage blockage. I've noticed some silicone inside the crankcase from when somebody tried to seal the oil pan.

I'll look up some parts, but can I go .030 under?

Looks like I need to drop the crank and get it ground. I wasn't expecting to split the tractor, but I might as well do it right and not regret it later.

Roger

 

[Roger in Manitoba]

Will the machine shaft know what the standard size of the journals is?

What is the standard size? Where can I find this information?

 

[spdljohn]

Take the crank to an engine machine shop. They will true it up and turn it down and they can even order your new bearings for you. They will be able to look up the correct journal dimensions. Unfortunately if the main bearing is shot the surface on the crank is probably scored up pretty bad too which means you can't simply slap a new bearing in and keep going (for very long at least).

 

[steve loosemore]

You need a shop manual for your model before tearing down an engine. This info will be in the manual, and also disassembly, inspection, and assembly instructions. They were written for professionals. This site and others have them.

 

[Roger in Manitoba]

The shop manual has been ordered, and I"m waiting for it to show up.

I"m hoping the crank details will be in there. But for the most part, I don"t the manual for taking the engine apart and putting it together. It seems straight forward. The only thing needed is the torque specs.

 

[Bob (Aust)]

[b:0afd3817b2]Roger.[/b:0afd3817b2] You found that knock I see!

Main and big end bearings come in .010", .020", .030" and .040" undersize.

Main Bearings:
Housing Bore: 2.6255" - 2.6250"
Radial thickness of bearings: .07225" - .07220"
Bearing bore diameter (fitted): 2.4815" - 2.4805"
Clearance new: .0025" - .0010"

Main Bearing Nut Torque: 80 - 85 lb ft.

Crankshaft:
Journal diameter: 2.4795 - 2.4790"

Big End:
Crankpin diameter: 2.0866" - 2.0861"
Bearing bore (fitted): 2.0885" - 2.0872"
Connecting rod bore: 2.2335" - 2.2327"
Radial thickness of bearings: .07275" - .07250"
Clearance new: .0024" - .0006"

Big End Nut Torque: 50 to 55 lb ft

Talk to the machine shop that will machine the crankshaft, I'm sure they will supply bearing shells. You will also need crankshaft thrust washers, 2 off, .093" - .091" is standard, permitted end float is .0117" to .0048".

Send me an email [email protected] and I will email you engine section of the Service Manual so you can get started until your manual arrives.

Bob in Oz
'53 TEA20

 

[Anonymous-0]

If that throw is torn up to bad , there are shops that can weld it up and then turn it to the proper size .

 

[Roger in Manitoba]

Yep, that bearing was bad all right. Funny though, the rest of the bearings are really good. In fact, I would say that this engine was rebuilt within the last couple of years and saw low hours on it. Not sure why this bearing went. Maybe it was the wrong one put in, blocked oil passage. I don't know. Too bad. It's a lot of work to get the crank out. Anyways, it's off the the shop today to get fixed up. I'll know when they're done what size of bearings to order, and then it'll be good as new.

I'm thinking of not rebuilding the oil pump. It looks really good. And I'm pretty sure that this bearing was the cause of the lack of oil pressure...

 

[Bob (Aust)]

[b:8b7944f6ec]Roger.[/b:8b7944f6ec] One failed big end bearing will not be the cause of zero oil pressure. The bearing failed because it did not get adequate lubrication - not the other way around.

[i:8b7944f6ec]"I'm thinking of not rebuilding the oil pump."[/i:8b7944f6ec]

I take it you are a gambling man?

:lol:

Bob

 

[Roger in Manitoba]

If I was a gambling man, I would have just put in thicker oil and hoped the oil pressure would come back up.

I was only "thinking" of not rebuilding it. I'm just surprised at the price for a small rotor for this pump. But, I've gone this far, might as well do it, eh?

Roger

 

[Roger in Manitoba]

Do you know of any other suppliers for the oil pump rebuild kit for my 52 tea-20? The price on this site seems a bit high.

Roger

 

[Bob (Aust)]

[b:4d3ff61c41]Roger[/b:4d3ff61c41]. I'm in Australia so can't really help you in Canada. However, contact your local AGCO - Massey Ferguson Dealer as they are usually a distributor for Sparex after market parts. The Sparex part number is S.61996 (Manuf Part No 827501M1 or 827501M91).

BareCo also provide a replacement oil pump, BareCo Part No B2257 but I don't think you can get BareCo in Canada, only the USA.

Bob in Oz
'53 TEA20

 

[Roger in Manitoba]

Still waiting to pick up the crank from the shop. The big end was at 0.020 under already, and they had to go to 0.040. The mains were 0.010 under, and they went to 0.020 under. So, I can still get bearings.

I checked all of the oil passages, and everything is clear. Good to know.

I've been scouring the net for places that will shop to Canada, and finally found that I can get Sparex parts from a tractor shop only a half hour drive away from me.

The connecting rod that had the bad bearing in it looked a bit damaged. It doesn't look too bad, and I was just thinking of cleaning it up. My thought was that the bearing would cover up any marks in the connecting rod surface, and since the bearing doesn't turn in the connecting rod, it should be OK.

I hope to start bolting this back together soon.