Model A cam removal

Ralph46

Member
Hello,
I'm in the process of trying to get the cam out of a 46 A and am kinda stuck. I've been following the IT manual and it's not very specific but I have the timing gear cover and flywheel off and have also removed the left side cam bearing. I know the governer has to come off to pull the cam gear out from the top. Does the entire fan shaft have to come out with it or can I disconnect it from the box first? Also I've read the lifter block has to be loosened, how do I go about that? Does the oil pump need to be removed entirely? I've never worked on one of these machines before so any help is very appreciated. Thanks
 
Only question I have experience with is the one about removing fan shaft from governor for easier governor removal. No, you will find that you'll need to remove the fan shroud bolts and hang the shroud behind the fan to gain enough room to get the fan away from the radiator too. It's tight and not enough room so the fan shaft comes with the governor if the radiator is still mounted. Remove radiator and then yes you can remove the fan shaft as a separate item from governor. And it's almost worth the bother to remove radiator just to remove the fan shaft as a separate item.
 
Maybe someone knows a shortcut, but I had to disassemble the entire engine. The cam was the last thing out and the first item in reassembly.
 
Timing gear cover ? not sure what that is on a 2 cyl. ?
The reduction cover has to come off as I think you can slip the cam out that side after the LH bearing is off and the gear is loose. I think I read about it in the repair manuals.
I have not removed any Cams as that being the only operation to do. I was always doing a complete tear down for either restoration or parting them out.
I'd remove the fan and gov. housing both as it sounds like the gov. has to come off anyhow to get the cam follower bracket loose, and keep track of the shim gaskets. Most of these the governors are in BAD need of attention and you can set them up on a workbench with both pieces off.
 

Yes I meant the reduction cover. So if I pull the radiator I can remove the fan shaft from the governor? Do I have to worry about anything coming/falling out with it? Just a backstory, the whole reason I'm taking the cam out in the first place is because sonehow the bolts that hold the cam gear into the collar on the cam broke. Previous owner said he was running a cordwood saw when it just quit. The problem now is I don't have enough play to slide the gear off the cam because the very top of that collar is hitting the engine casting. Here's a pic to show what I mean. Note the broken bolts in the gear:

48437.jpg
 
The bolt you refer to might be a broken threaded stud and some people change it out for a real bolt. If there is more than one broke off in the cam gear, you might try to turn them out with a sharp pick/chisel as they should back out pretty easy. So they came with one stud in the cam gear and two bolts and some would just roll it around to the right timing spot and fasten it back together with two new bolts instead of three. That would be hands down the easier way to go unless a short cut like that would keep you up at nights with worry. I would sleep just fine, mine was found with all three bolts (someone was in there before me) loose as a goose and I just re-tightened them. Very many report similar loose bolts found and several have fixed their entirely spinning cam gear like yours with just two bolts as well. 3/8 coarse.

If you pull the radiator, the fan shaft will just come out with three bolts removed. Nothing will fall apart as the fan shaft is an assembled unit and just bolts in. You should pay strict attention to shim pack/gasket stack however as this is one half of the issue of how to set the backlash on the fan gears. Other shim stack is the left governor shaft bearing cover gaskets.
 

So more than likely the bolts were loose and just let go when it was running open with the saw. If I can get it bolted back together the only problem would be that I already took the bearing off, don't think I'd be able to get a new one on with the cam in the tractor. Also what does that thrust plate do? As you can see it's pretty mangled. Not sure how important it is to the cam?
 

Some people have suggested that the camshaft was the first part of the tractor that started down the production line and everything else was bolted on around it.
 
You should be able to take the governor housing off without removing the fanshaft from the tractor. Loosen the hood up and strap it to the steering rod. If you tip the
governor right it will come out with the fanshaft still in the tractor. You might have to unbolt it from the front bracket and slide it ahead some. Watch out for the radiator
though. You will have to get the bearing race off the cam to get it out of the gear. You need to loosen the lifter block and you will need to drop the oil pump to get the lifter
block to move out of the way. Don't forget to take the oil line to the governor off before trying to remove it. Have the cam reground while you have it out for a cheap
performance fix also.
 
That's not a thrust plate. It is a locking plate to keep the bolts and nut from working loose. You can change the bearing without removing the cam once you have the old race
off. Just warm the new bearing up and it will slide on.
 

Do you think I can get away with lock washers on the bolts if I cut it off? Also how do I make sure the cam is in proper timing when I bolt it back to the cam gear? I guess there is only 3 ways it can go.
 
I was wondering why it had to come out.I thought maybe you were making a puller ? Likely it does not need to come out to repair it. I had one of the same year I bought that quit running when they were cultivating. I think for some odd reason that model had that problem as I have heard of others. Maybe a new person on the assembly line didn't tighten them enough ?
I was able to drill out what was left of my bolts. IIRC one or all came out once the bit caught them. I was able to get the bit in by moving the cam enough from the play it has. All I removed was the top engine cover, flywheel,LH cam bearing cover and bearing. I also likely removed the LH gov. end cap. I was thinking the lock plate was U shaped and could slip in over the cam ? I have replaced several LH cam bearings on A's and 60's as they are a problem spot. Heat the new bearing cone up and it will pop right on the cam.
 

Good to know I can get the new bearing on with the cam in. Any advice on making sure the cam is in the proper position when I bolt it back to the cam gear?
 
For some reason I think there was an extra hole in the cam or gear but not in both and I could see the old spot where it had sat before. Then to double check it you use the marks on the flywheel for the LH exh open.
 
I seem to think in one of the manuals it mentioned about either the first lobe or that extra hole pointed to a certain spot on the gear. I'll have to see if I can find that info. Back when I did mine I likely had a few parts tractors apart to compare it to. I don't think I have an A cam and gear left around here anymore.
Valve cover will need to come off and rocker arm assembly as well to relieve any pressure from the cam so you can move it around better.
Look for the timing marks on the crank gear and cam gear these are on the inside (crankcase side) of the gears. You will need to verify alignment at some point. When aligned the #1 (which is the LH side) crank rod journal will not be straight back or ahead but rather at an odd angle. I can't recall if it is slightly up or down ? Hopefully you can carefully rotate the crank back up to TDC and keep them in mesh.
With the #1 rod journal to the front as in top dead center I'm guessing the cam lobes for that side will need to point to the back so the valves can be fully closed. I'd start there and stick some bolts in the cam & gear and then verify cam gear to crank gear timing marks.
 

Ok thank you I will let you know how I make out, hopefully I can get it done this weekend as long as it isn't raining
 

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