TO30 camshaft problem

I have started evaluating a TO30 (Z129 engine)that I purchased 2 years ago and parked in the barn until I had the time to work on it. When I bought it I was able to get it to "run" and compression was OK and even, but it has obviously been neglected for a long time and the oil was black, but no water in it.

I dropped the pan and saw that the aluminum drive gear on the oil pump was pretty chewed up, so I put in a rebuilt pump. The timing gears looked a little beat up too, so I pulled the timing cover to replace them also.

Well, I found the cause of the gear wear. The camshaft gear is wobbly on the camshaft! I have not been able to remove the retaining nut to get the gear off. If I hold the gear from rotating (by keeping the crank from turning) the camshaft turns with the nut. I noticed this when the rockers started to move. So, probably the Woodruff key is sheared or dropped out, the gear is wallowed, and the end of the camshaft is worn, but I have not been able to take off the nut that retains the inside part of the governor and the camshaft timing gear to really see.

OK, so here are my questions for someone who has been here before and could suggest what might work:
1. How can I keep the camshaft from turning (from inside the crankcase) while loosening the retaining nut? Is it normal rotation thread? Would vise grips on the rough part of the camshaft be OK to keep it from turning? Any other ideas?
2. Because the engine is not inverted (still on tractor) what is a good way to keep the tappets from dropping out when I do get the cam to come out? I have read about using "pencil magnets" down the pushrod holes. Anyone have luck this way?
3. How do I keep track of the timing issues as I go along? I documented the relative position of crank, cam, distributor rotor and flywheel before I started messing things up, so I hope I can get the timing back. Oddly, the marks on the timing gears were together when piston #4 was at compression top dead center rather than piston #1 as I have read. The distributor rotor was pointed to plug wire #4. When #1 was at firing TDC the marks on the cam gear were 180o off. Does this make any difference as long as the ignition and valve timing are synchronized?

Please forgive this long thread. I wanted to give enough information so someone with experience with these engines could point me in the right direction. Thanks for taking the time to read it.
John

Can you get to the nut with a impact wrench . If the cam is no good , how about grinding the head of the bolt off with a cut off tool ?
You might be able to hold the lifters with good cloths pins through the side covers .

I have a good used cam with gear for sale. I also have other Freguson parts. Thanks Jim --No-Advertising-in-Forums

Hi Folks,
Thanks for the replies to my questions. The impact wrench with a vise grip pliers on the camshaft did the trick in getting the camshaft gear retaining nut off. Thank you Dick for the suggestion!
What I discovered was that the camshaft timing gear was broken concentrically around the hub of the gear, allowing the camshaft to turn separately from the body of the gear, or vice versa. The camshaft was still in good shape with the hub of the gear still firmly keyed to it. So I won"t need to replace it. Yea!
I am wondering if this was a weak part of the cam gear casting. The breakt ran through the two large access holes in the face of the gear and around the hub on the back of the gear. I could not see the problem until I removed the nut holding the back part of the governor assembly and the cam gear onto the camshaft.
I guess it was luck that I could get the tractor to run at all, so I have named her "Old Lucky". Hopefully a new camshaft gear will get her running properly.
There is still the nagging question of why the gear broke in the first place...
Anyway I hope this thread will help someone else with a similar issue.
Thanks for providing a great source of information to us Ferguson Folks.
John