Farmall M, Misc Questions..

Bryce Frazier · Nov 8, 2015

So, I have a few odd ball question for you guys on my 3 M's....

1st of all, the engine. On ONE of them, it is a 1939 or 1940 Farmall M, the oil filter housing is MUCH larger than the other two? Also, the air cleaner assembly, and front fuel tank support are different as well?

2nd, the Trans. On the actual shift rod, the "Old" M has a bent one, then the one that I am fixing, is straight, like my H, and then the other "Newer" one has a bent one again? I thought only Supers had a bent stick?

I am fairly sure that the "old" M is different due to the year of production right? It has a different PTO as well...

I don't know which of the "newer" M's are newer than the other, but I know one is a 1948, and that is the one with the straight shift stick.

Next, I want to know if there is ANY other difference in the engines between and "All Fuel" engine, and a "X1 Gas" engine? The newest one I just got has the X1 engine in it, but is stuck (not bad I don't think though). We are going to try to get it freed up this winter, but if that doesn't work, I want to try to boost the power in the one that runs. Can I just swap heads? Or is it more complicated than that?

Thanks guys! Bryce

greenmech · Nov 8, 2015

Some of the older Farmalls had a taller oil filter. Ron Mn

DeltaRed · Nov 8, 2015

I've had 5 or 6 Ms over the years,heres a bit of what I have learned.If it's a true '39,it will have the 'water trough' deck.All others had the common flat deck.Later M had a bent stick. The Super weht back to the straight stick.I acctually bent the stick of my Super to get out of the way from my leg when in low gear. The earliest M had the small(1 1/8") shaft.You can easily change it to the larger (1 3/8") shaft. The distilate/all fuel piston should be a flat top.The Gas is probably a domed piston.Something I learned with an F20. Distilate/kerosene uses less oxygen than gasoline. Consequently it had a smaller hole in the venturi,cause black smoke,running very rich,tended to foul plugs with black soot....We 'bored out' the venturi. It could then get more oxygen,and ran clear and had more power. An old Harley mechanic friend figgured this one out.The earlier Ms used a much bigger around filter. The later and Supers used a 'thinner' filter.Filter bases could be changed. My parts SMTA has the earlier big filter. Why??? Maybe a PO though extra filtering capacity would lengthen the life or the engine?I think you could swap heads,but not entirely sure.Just make sure there is no valve interference.Domed pistons would help the most.Find a set of 8000 ft pistons.I also tweeked the governor a bit.Got a hundred or so more rpm. Really helps on the hard pulls.You can date them by just looking at the date codes on the engine/trans/rear end houseings.IH acctually changed a fair amount of stuff during the production years.'Improvements'.Any more questions,or talk tractors,just call me.You have my number. Steve

DR. EVIL · Nov 8, 2015

About late 1942 IH started recommending and installing Purolater style oil filters. They were more efficient at removing dirt than the prior OEM filters so smaller filters could be used. M's used H filters, H filters shrunk in height to about 2/3rds prior height, M diesels did not change size. I think the Louisville tractors even used smaller filters.

DeltaRed · Nov 8, 2015

My '52 MD uses the large fat filter. had a 40 and 41 M that each used the same fat filter as the MD.Both 45 M and SuperM both use a tall skinny filter. The SH uses a short filter. The SC uses the same filter. Never checked/compared the diamater.Need to do that....

CenTex Farmall · Nov 8, 2015

The PTO and oil filter change have definite serial number breaks. In general, the PTO changed in 42 or 43, somewhere in there. Same thing with the oil filter housings. There's also a difference in crankshaft bearing size that changed about the time the oil filter did. I don't know on the shifter.

The distillate engine will have a lower compression head and had flat top pistons. Almost invariably, by this time, the engine has been rebuilt with higher compression piston. The distillate head had a larger combustion chamber and shorter valves. Complete heads will swap. What you really need to do is get the part number that is cast on the head and post it in the Farmall forum. The head may have already been swapped.

Have you looked at the casting numbers on the various pieces? That will tell you roughly when the tractor was made. We had an M one time that the serial number made it a '46 and the casting number on the torque tube, obviously, agreed. However, the castings on the engine, rear end and axle housings were from several years later. What had happened is that the torque tube had been replaced at some point. The castings dates told the story. I frequently see tractors that have been pieced together.

Sometimes people think they have an original tractor because they've owned it for 30 years but they forget about the 30 years before they owned it! I don't mean to imply that you are thinking that, just that I've seen that before.

Den N Ms · Nov 8, 2015

Bryce ,One the one that is stuck,now is the time to remove all the plugs and fill the cylinders with some cheap ATF,put the plugs back in and let it soak till you decide to work on it.It may be free by then.

Den N Ms · Nov 8, 2015

Bryce ,One the one that is stuck,now is the time to remove all the plugs and fill the cylinders with some cheap ATF,put the plugs back in and let it soak till you decide to work on it.It may be free by then.Keep the exhaust covered up.

D Slater · Nov 8, 2015

Oil filters were changed to the smaller diameter type at engine serial number 54394. Number should be stamped in the block in area below front spark plug. At this date the only way to know for sure what the difference in engines is to look and see what head and pistons are there. Thousands have had parts changed since new.
All shifters have a bend and several gear shifters were used, but tractors serial number 128007 up to when they put the battery box under seat on SM tractors should have a double bend. It was during 1947 when what they called the hydraulic seat attachment was first offered. SM and SMTA shifter used with a battery box under sear had a single bend.
Metal fuel tank front support was only used on tractors serial number 24214 and lower.
Double bend shifters were also sold by IH to replace some others without a double bend.

Kelly in tx · Nov 8, 2015

Bryce, does the one with the tall oil filter have the "hog trough" (indentation in the platform) so the seat suspension can travel? Does it have the original seat on it? If so, it is probably a 1939. It may be a bit rare. Does it happen to have a three or four digit serial number? If so, again, it may be a bit rare. Serial numbers began with 501 and went up to almost 300,000. Good luck with whatever you decide to do with your three "M's". Kelly in tx

Bryce Frazier · Nov 8, 2015

I am fairly sure that it has a 4 digit serial number... Not 3 for sure, I would have remembered that, but I was thinking that it was 4000 something?

The trough, well, I don't know. Someone has gone and bolted / welded an 1/2 inch steel plate all across the top of the platform, and then put the seat on top of it?!?! Not sure why they did that??

Bryce Frazier · Nov 8, 2015

Ya, I have it soaking in a mix of "good" things! Hoping that something good will happen by the time next spring gets here!

Bryce Frazier · Nov 8, 2015

I know exactly what you mean, as it is what I am doing!

I have these 3 M's, and am trying to build one complete one.. . So far, I have dropped the "Old" engine into the 1948 tractor, BUT, the 1948's torque tube had been replaced, so, I assume the serial number had as well, so I am back to the point of not knowing what year it is, but have just been calling it a 1948, because it is a good mix of things!

I hate mis matching things, but, the "old" one wasn't saveable, and all in all, the engine was really the only good thing on it. I just really badly want a nice running driving Farmall M, and as of today, I am REALLY close to that goal!

Bryce Frazier · Nov 8, 2015

Good to know Steve! Thanks!

I am curious to see what oil filter I can get my hands on, I suspect that BOTH the large, and smaller one are no longer in production, but perhaps the newer smaller on still is (in fact I am sure of that). But, I have that junk engine sitting here, and it has the smaller one on it, and it looks to me like I could just swap filter housing from the side of the blocks.. Not a project for this week, but I do plan on looking into it for sure!

DeltaRed · Nov 8, 2015

The filters are available from NAPA. The tall skinny one is NAPA #1125.They can even get oil filters for my F-12

D Slater · Nov 8, 2015

Transmission top with slot in it was on tractor serial numbers 501 to 9286. 9286 was built in Feb. 1940. Since the tractor has the stamped metal steering, air cleaner and fuel tank support its older than serial # 24215. 24215 was built in Nov. 1940. Tractor probably is lower than 9287 and has the slot top and they put the steel plate on to mount a different type seat than original. Early M tractors around with all original parts are pretty hard to find.

CenTex Farmall · Nov 8, 2015

Hey, a pieced together tractor is better than being made into harbor freight tools! I have one out back that is half SMTA and half '41 M.

Take the best parts and make a good one. Keep the rest for spare parts. Paint your parts tractors into "yard art" so your loved ones won't complain. I should do that.

mschwartz · Nov 8, 2015

Hello Bryce, the larger diameter filter on the early m motor should be a 1155 filter, newer M filter is the 1125 and the shorter one if someone has mixed and matched parts will be the 1172 like on your C. As far as swapping heads I think that will be fine but the Kero/dist head has different length valves vs the gas heads due to the change in combustion chamber. I'm sure someone else will know but the pushrods might be different also. One of my early M's has had a gas head put on it during an earlier part of its life but is still running the cast 3 7/8 pistons with no problems. Good luck, Mike

oldtanker · Nov 8, 2015

Why exactly do you need more power out of it besides your age? While you can get more power out of it unless it's done right you will only have more problems with it. From what I've seen you post right now a 40 some HP PTO tractor should be more than enough. When you really need more buy a bigger tractor slightly newer with decent hydraulics!

Rick

Bryce Frazier · Nov 8, 2015

ya, we had that though... I could swap out push rods too? Might be safer just to do that, wether they are different or not?!

Bryce Frazier · Nov 8, 2015

HA! My loved one (mom) doesn't even like restored tractors in her front yard!!! Oddly enough though, she is pretty found of my GMC 6000 truck.... ??

I WANT an M for me, and for me, I would rather know that I busted a$$ and made MYSELF a nice machine, that I KNOW if a good one! That is more important to me, than being numbers correct....

Bryce Frazier · Nov 8, 2015

Well, the one with the gasser engine is stuck, so, I figured if I could easily swap heads, and get a few more ponies out of my good engine, then why not? Seems to make sense to me!! This one is going to have an M&W live pump on it, with 2 remotes pretty soon... Already has Charlynn Power Steering, so, why not! It is a TOY, so I am going to play with it!

oldtanker · Nov 9, 2015

OK I was just asking.

Rick

D Slater · Nov 9, 2015

If it's the early M you want to put a gas head on? Take a look at the studs mounting the manifold to head. If 7/16 diameter instead of 3/8 the head has already been changed to something else. Lots of early ones have had the engine block replaced also. That tractor maybe was used as the main tractor on some farms for 15 to 20 years or more and rebuilt several times. After gasoline was common lots were rebuilt with gasoline parts. Most old M tractors have a 50 50 chance or less of having the original head still on them.
You could already have a gas head, never know until you look.

Bill Hires · Nov 9, 2015

I have a paper with the title What Makes a 1939 H or M Unique? By: Justin Weber If you would like a copy give me your mailing address and I will send you a copy. The Baldwin Filter book # for their oil filter for this tractor up to serial number 59394 is PT72. Later PT70

Bryce Frazier · Nov 9, 2015

Okay, I'll have a look! Seems to me, that the manifold is held on with BOLTS, and they are 3/8 looking, but I am not sure.

Dad is going to bring home a bore scope, and we are going to look around inside both of the engines, and see what's what!

Where are the casting numbers for the engine and the head?

1206SWMO · Nov 9, 2015

I talked to your son Steve when he pulled at Nevada this summer..Does this tractor look familiar..

Bryce Frazier · Nov 9, 2015

Okay, here are some numbers off of the good running machine.

The serial number that CAME on the tractor with this engine in it, is FBK - 8717

The engines tag is 4/15/ O (or 0)??

The heads tag is 1/11/J

Thoughts?

Bryce Frazier · Nov 9, 2015

Just posted some numbers as well, but the bolts are 9/16 head's, so that would more than likely make then 3/8 bolts correct?

Another thing I thought about though, was the manifolds. Would the "Distillate/all fuel" engine have one of those large heater chambers in the manifold? This one just looks like a normal gasser manifold to me...

D Slater · Nov 9, 2015

8717 was built in Jan. 1940. Probably the original low compression head with 3/8 threads in head for a manifold attachment. Good chance it was a non gas manifold originally. Head was cast close to tractor build time. If 4-15-O is the date code on block that makes it cast in 4-15-1945. Hard to tell a O from Q on them. If a Q 1947.
If the engine came from another M it will have a serial number stamped in the block just above the right side cover on a raised flat area near front and in a area below the first spark plug. First three letters of a prefix before the number would be FBK. If the block was purchased as a replacement it may not have a serial number. Should have a 4 number block casting number on block above oil filter in raised numbers. Will have a two letter suffix. if no serial number the cast number and suffix letters may narrow the ID down.

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