Camshaft failures in tractors?

Just posting a general question here. I have been working on autos and tractors for 50 years. I replaced many a failed camshaft in cars
years back. Mostly just Chevys back in the 60s and 70s. They were known for poor quality cams and lifters.

When it comes to farm tractors? I think I have only ever seen one worn-down camshaft in my life. That was on a Minne-Moline.

Up to this point, I have assumed that tractor/industrial camshafts were made of more hardened steel instead of the way Chevy cams were with
soft castings and a thin surface hardening.

I am asking this because of a Ford Jubilee I just picked up. Engine sounded fine after I got the fuel system cleaned up after many years
of sitting. To my surprise though. I pulled the valve cover off to adjust the valve-lash. I found one rocker with over 1/4" clearance.
It is not from a loose adjuster. Something is obviously wrong inside the engine. I suspect a worn cam lobe. I am going to pull the oil-pan
off today and peek inside. I never messed with Ford tractors much but also never heard any bad cam stories about them.

The worst worn cam I've ever seen on a tractor was on my brother's SC Case years ago. He had installed a new sleeve set, but still didn't run right. New cam and both gears got it running well. Also had an Oliver 1950T with a worn exhaust cam lobe, but owner just lived with it. The 560 diesel I use for tractor drives only has a slightly worn exhaust lobe on number six, just use it as is and has not gotten any worse so far.

Lots of engines out there that have been rebuilt then lots of ignition,carburarion or fuel injection work/rework/re-re-work. Then the frustrated owner and shop just accept that it is an old machine and unaware that a simple regrind was all that was needed.
Cams and followers do wear but most rebuilders are oblivious to the fact .

A lot of difference in RPS between tractors and cars. --------Loren

I think the main reasons are not so much as hardness but that they're low revving engines with lower valve lift and valve spring forces. I recently rebuilt a Buda 230 gas that had two bad lobes and since it was a total rebuild I decided to go the extra $475 for welding and regrind. Just my opinion.

A cam grind no doubt would help with performance but I wouldn't do it just because a lifter is out of adjustment. You don't know who adjusted them and if they had the cam turned to the right spot when they were set. A lot of variables there.

Yea they do ware . and i have had them re3built and reground , some i have refaced the lifters/ cam followers and others i have replaced them.

We changed a handful of them out in the GVI I think it was in the MM colors seems like it was the same as a MF 97 last one we did was in 1970,, so I may have the models mixed

I expect if a person used modern automotive oil without any Zink it could cause wear, but with the low rpm and valve spring pressure probably insignificant. Not like a motorcycle engine that runs 10,000 rpm!

Early IH 86 models with 400 series engines had a lot of camshaft trouble. On the real bad ones the exhaust valve was late opening and the exhaust would try to get out the intake valve when it opened. Easy to hear in the air intake.

I have seen cams wear a bit on the high spots of the ramps. Often not a huge issue when the cam has a lot of hardened surface, or is all
forged steel like in my Ford IH diesel pickup.

Chevy cams in the 70s were soft castings with a very thing hardened surface (Parkerized). One that thin layer wore through, the cam wore down
to nothing fast.

This Ford Jubilee with the 134 engine seems to have wear at the bottom of the cam, not on the high spot. Very odd. I will know more later.

When it comes to custom cam grinding? I have to wonder how a cam is rehardened if it is a soft casting?

This one so far seems to be very odd. The wear does not seem to be on the high ramp of the cam lobe. Wear seems to be on a low spot. We yanked out many Chevy cams with the high spots worn right off.

This one has my brain a little twisted. I guess I will find out what the cause is later today. The valve-lash adjustment was right-on when done the way Ford recommends it. When set at .016", it gets to a certain spot and then gets so loose the pushrod falls out sideways from the rockerarm.

Have you checked the lift compared to the others?

Usually just the top of the lobe wears off leaving the base unworn. It may take the bottom off the lifter though, giving the extra clearance.

Before going any deeper, check the lift with a dial indicator, see if it's the same as another that is in tolerance.

Could be a bad pushrod, bad rocker. Is the valve the same height as the others? Some used lash caps, could be missing.

Neighbor has a Jubilee that he got after his uncle passed. It was only running on 3 cylinders. When I pulled the valve cover, the push rods for that cylinder were laying sideways under it. When we started it after putting push rods back in and adjusting, it hammered like a bearing was out. Upon further investigation we found that one of the lifters on that cylinder had broken about half of the bottom off and damaged the cam. Replacing the cam and the lifters on that cylinder fixed the problem.

Update. Now I am feeling a little dumb. I pulled off the oil pan and looked at the cam. The problem is with the intake-valve area for #1 cylinder. As I said before, I'd adjust the lash to .016" and rotate the engine a bit. Then would have a 1/4" lash and pushrod would fall out.

Ends up the camshaft is fine. After looking more closely, I see now the intake-valve itself is coming all the way up very fast. I never suspect this sort of thing since I did two different compression tests on this tractor. I tested it before starting after it sat for years. I also tested it after running it for awhile. Both times, compression read fine on all four cylinders. So finding an intake valve sticking like this is a surprise. Note - all clean and not rust inside either. Very clean looking.

So now I have to decide if I want to pull the head - or try to run it and see what happens? It looks like it was a problem before it had gone into "long-term" storage for 7-8 years. I guess I will pull the rocker-shaft off, and valve-spring and see if there is any visible problem on top that I doubt.

I have my own cylinder-head equipment for doing a valve-job myself. No huge big deal for a little four cylinder. Just kind of irks me since this thing tested perfect with a compression test and engine sounds pretty good - except when the pushrod falls out of place.

you're right about them chevys',. dad bought a pick-up new in 68,with the 350, and it wiped a lobe off the cam..lucky it was still under warranty.

Maybe that particular lobe, for some reason, didn't get hardened all the way around. The lobe wore on the soft spot, which was the low side, and now it has enough clearance to let the push rod fall out.