The Fordson Tractor Pages Forum

Hi,

Just bought a Fordson SM, had a rattle in the engine when i bought it so i have pulled it apart.

Big-end on number 3 has spun , i have to check the jounal with a micrometer , doesn't look so bad.
Crank on 40 thou o/s shells.
Other journals look OK ,but the shells have had a hard life, oil changes/dirty oil?

The oil pick-up looks pretty suspect spring loaded and i wonder how it seals and works if the oil is low because oil starvation looks to be a problem if the strainer and pipe don't fit properly?

Is the oil filter a by-pass or does all the oil go through the filter and then to the crank?
Meaning if the filter is clogged is low oil pressure a result?

Oil pumps do they wear out on these and are bits about to fix the pump?

Thanks.

There are no seals on the pick up pipe, the only rare problem in that area over the years has been a crack in the pipe. The filter is usually under the oil in the sump and the pump picks up without problems.

0.040" u/s sounds like new crank territory. Check one out, they are far cheaper than you might think. You may also want to check the cam shaft bearings as well.

The oil pressure can be quite low and the tractor run happily. Back in the day, oil pressures of around 10 psi were common with the engine going on for many years work trouble free.

Oil pumps do wear out and new ones are available but be careful, they are made in the "Land of Nearly Right" and may not fit easily.

Yes it is a bypass system.

Brian ,
had thought of a crank, waiting on a price.

Why number 3 journal to spin the bearing shells?
Do the cranks get sluged up and prevent oil flow?

I have had two Majors with spun bearings on the crank and the both of them were on the #2 journal.
Be sure to check the oil filter assembly, both of the two bad engines of mine were missing the proper spring/seal assembly in the bottom of the filter canister allowing contaminants to completely bypass the filter.

Pat

Good Day

If you do not know how long the engine may have been run with the damage, it is worth checking the con rod on No 3 for straightness and its end cap fasteners, as they may have been subjected to stresses beyond their capability.

Regards

Tim E

Reading the first post, I assumed you spun # 3 main bearing? Or is it # 3 Rod? As the others have said, 0.040 undersize is time for a new crank. Dandy Dave!

Pat,
thanks for the clues on the oil filter assembly.
I bought the tractor with a light rattle in the big-end, they had another tractor were using and the story was that when it developed the noise they stopped the tractor and just bought another.
I loaded it on a truck and it was delivered to the farm , i then pulled it apart without using it.

Oddly what you say about the oil filter seems to fit?
"Be sure to check the oil filter assembly, both of the two bad engines of mine were missing the proper spring/seal assembly in the bottom of the filter canister allowing contaminants to completely bypass the filter."
With your two engines what were the repairs and any subsequent problems?

*There was near nothing in the way of sediment in the sump and the other bearing shells were scored as if the oil was not filtered properly?
I will pull the filter apart and see what is missing, next time i am in the shed
The crank doesn't look bad at all, not scored and i was surprised although there wasn't a bad noise, but i will mic' it up.

Hi Berridale
I Have a crank here that has been ground to 30 thou. I would be changing the crank as others have said . it is a lot of work to put a nearly right crank back, then find you got problems later . My engine machine shop guy has 50 years experience in Major motors and grinding the cranks.
He said 40 on them is a big risk as the hardening treatment was not usually 40 thou deep, and rapid wear can occur after 30 thou grind. this is what happened to mine, and have seen a few more the same . I know this motor here was re built in the 80's and it only ran for 5-600 hours after, I know the previous owner very well .
My crank has some pretty bad ridges on the mains, and is not worth repairing. Yours may do a similar thing, and a 40 grind tells me the last failure was pretty spectacular, or the crank was way out of round, to need that much off to correct it. you may even find the spec is slightly over the 40 to get it close, seen 1 crank like that here, result was low oil pressure on a motor that had new pump / grind and new bearings, before the guy got the tractor. . After years of fixing stuff the way customers wallets want it done , not necessarily the right way in some cases. I became a fan of the "Mike Holmes Make it right school"
Regards Robert

Berridale, the two engines that I had the issues with didn’t seem to have significant wear/damage to the rest of the engine, one got nothing more than a repaired or replacement crank, bearings and rings. The other got a complete rebuild, but the liners were bad from rust in that one. If I remember correctly they both got a replacement connecting rod.

Pat

Pat ,
were the liner seats corroded?

Guys,
thanks for the info on the hardening depth!

That particular tractor had been brought home from a scrapyard, (Apparently I have a bad habit of bringing home other peoples junk) the engine was tight from water sitting in the cylinders. The seats looked good, just a little too much pitting on the inside of the liners.

Pat