Model H Cam Shaft Strength

primerk5

Member
I just picked up an H over the weekend at a local auction. I wasn't aware at the time that the clutch pulley ran off the end of the Cam. When I think of a cam shaft i think of a small thing that if you drop it it will snap in half. (Small Block Chevy) It seems odd that they would use it as a power source and i'm sure that John Deere had tested this past the breaking point. John Deere advertised it as a one-two plow and i just can't see a cam shaft taking that kind of abuse.

Is it really that strong? I don't plan to do much with this little tractor, mainly a restoration and toy around with it. I had thought about pulling a small david bradley manure spreader but i'm not sure i want to do that depending on the weight the spreader may get to when loaded.
 
I use the belt pulley on mine quite a bit. Also use it to cultivate and have dragged some logs with it.
Don't worry about the camshaft.
Richard in NW SC
 
I have a 1941 H with PTO and live hydraulics..I have the mounted 1 bottom plow and cultivators for it..I also have a brand new crankshaft for one,,if any one should need one...they look kinda odd with nothing on the left end of them...
 
They really aren't that scarce.
I see them occasionally.
I just recently deleted of a bunch of H contacts
from my phone. One had a loaded one fixed up.
Don't know if he ever got rid of it. Thing is Alabama
is pretty far from the closest point in Canada.
 
primerk5, if that "H" camshaft was in your hands you would see it's a lot more robust than a camshaft from an automobile engine. And there are no supporting bearings except at the sides of the engine case, so that camshaft has to bridge across the entire engine case and operate the valve train and there is a helical gear machined into the cam at mid-span that operates the oil pump. So that cam does a lot; it withstands all the side forces and bending from the belt pulley, valve train, and oil pump, and also must withstand the torsion of driving the transmission and PTO. But it's actually a pretty beefy unit. Anyway, the power of the "H" is only about 15 HP on a good day so there isn't a lot torsion that it has to carry.

Deere decided to put the belt pulley/clutch on the end of the cam for several reasons - one is that the little 99.7 cubic inch engine ran at a much high RPM than its larger brothers, so the engineers took advantage of the 2:1 reduction of the camshaft speed with respect to engine speed, and it may have eliminated the need for another gear reduction in the transmission. Another reason is the lower input speed to the transmission also lessened gear noise.
 
(quoted from post at 18:58:25 09/28/15) primerk5, if that "H" camshaft was in your hands you would see it's a lot more robust than a camshaft from an automobile engine. And there are no supporting bearings except at the sides of the engine case, so that camshaft has to bridge across the entire engine case and operate the valve train and there is a helical gear machined into the cam at mid-span that operates the oil pump. So that cam does a lot; it withstands all the side forces and bending from the belt pulley, valve train, and oil pump, and also must withstand the torsion of driving the transmission and PTO. But it's actually a pretty beefy unit. Anyway, the power of the "H" is only about 15 HP on a good day so there isn't a lot torsion that it has to carry.

I figured it had to be pretty strong to hold up to potential abuse. I'm not likely to see the one in my unit as it doesn't appear to have any issues that will cause me to open anything up. Thanks for the info!
 
Deere was trying to get a tractor to compete better with the Case, Model VA or VAC I think, than did the Deere Model L/LA. The Case sold for a very low price so manufacturing cost, thus price, for the Deere H was critical. I suppose some analysis showed the tractor could be lower cost by getting the first engine rpm speed reduction for "free" if taken off the camshaft - even if it meant the belt pulley turned the "wrong" way. As a kid, we used the H on the belt a lot. Most belt-driven machines were designed for the belt to be twisted. We just didn't twist the belt when using the H.
 
(quoted from post at 19:19:12 09/28/15) Plow with one each fall, it does surprisingly well with plow made for it. https://youtube.com/watch?v=vja3tIzkRjo

Watching your video tells me that mine had a plow mounted to it at some point in its life. The repaints it has had thus far in its life you can see where there are indentations of some sort of irons mounted to the sides of the frame and the ones that hold the front of your plow appear to be the same style irons going in the same directions of the imprint you can see in the old paint.
 
Over the years I have had the opportunity to own and also part out ALOT of model H John Deere's. Way more than the average fellow. I do not every remember seeing a broken camshaft in them. Or any other 2 cyl. for that matter. You will however find most of them in need of a left hand ball bearing that supports the cam and also controls the endplay. Commonly found bearing and pretty easy to change. Cam gears can many times show excessive wear and once in awhile one is loose on the cam splines. I have seen several with visible wear on the lobes and I think some of that is due to rust forming from moisture and then when ran again it just wears them down faster.
Buy it, enjoy it, and work it.
 
(quoted from post at 07:12:49 09/29/15) Deere was trying to get a tractor to compete better with the Case, Model VA or VAC I think, than did the Deere Model L/LA. The Case sold for a very low price so manufacturing cost, thus price, for the Deere H was critical. I suppose some analysis showed the tractor could be lower cost by getting the first engine rpm speed reduction for "free" if taken off the camshaft - even if it meant the belt pulley turned the "wrong" way. As a kid, we used the H on the belt a lot. Most belt-driven machines were designed for the belt to be twisted. We just didn't twist the belt when using the H.

One of my favourite tractor stories was from Clooney. He did not tell very many but the one about the H was priceless.
 
(quoted from post at 05:24:21 09/29/15) Over the years I have had the opportunity to own and also part out ALOT of model H John Deere's. Way more than the average fellow.

Any of you guys have an oil filter spring. Mine is missing from my tractor.

Thanks
 

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