trainzkid88 wrote:

to use a coupler like i described how i would do it is use the clutch pressure plate mounting bolts and dowels bolt a 1/2 inch steel disc to that that has a spigot to go into the pilot bearing bore and a shaft to take the coupler or v-pulley on the out side. the spigot and shaft would be one piece of high grade bright shaft machined to suit recessed and plug welded into the disc. the spigot would be a nice sliding fit into the fly wheel bore so no bearing or bush to vibrate. and all of this nice and close to the flywheel as possible to reduce side loading. i would probably go up a size on the clutch bolts so if 5/16 i would use 3/8 or 7/16. the pressure plate can be the template.
 

D2 and D4's of that era use a clutch that is similar to the steering clutch albeit with only one disk, therefor the pressure plate does not bolt to the flywheel.In fact the only bolt holes in the flywheel are for mounting it to the crankshaft
We have two of the tire style couplers at work on some big vacuum pumps. They work well in that application but they are very agricultural and there are far better couplings out there.  They also take a lot of room and need access to both sides to do up the clamps.They are also for slight misalignment and won't help with vibration issues.
I can assume Jack has used a bronze bush to allow easy removal next time without galling and without wear inside the flywheel bore.
My old Automotive TAFE teacher told me of a trick to help eliminate vibrations in tail shafts that may work here. You put a hose clamp around the shaft and tighten it up firm but not too tight then start up and run the machine. The idea is that the heavy part of the hose clamp will move due to the vibrations and stop when the vibrations stop or lessen. I have never tried it but he swore it worked.
As for the pilot engine, my father ran a 5R D6 for most of its lifetime and never destroyed pony motors and never did anything special except turn it off with the fuel tap and not the ignition kill switch. Maybe the bigger pilot motors were more reliable.
 

ive heard of that trick too. poor mans way of adding a balance weight. but if it works who cares. its worth a try and not every town has a drive shaft service close by. best of all its cheap and if it dont work easy to remove.

bigger heavier components different bushing materials might make all the difference to reliability. who knows what life our machine had before the cousins bought it. simply a d6 having a longer track might make all the difference how the weights and vibrations throw.

you could still do as i suggested but you would have to drill the fly wheel and get it rebalanced most engine reco shops can do it but not all have the gear. its not cheap either. and the fun is getting a accurate bolt pattern so its close to being in balance any way and the adapter would need to be balanced with it. oh the fun of adapting old gear to work with other things.

if they made that engine series as a industrial engine the ideal would be to find a bell housing and power take off assembly off another motor. but i bet there as rare as hens teeth.

Looks like you got the problem sorted out. First off, I used bearing bronze because it will never realize a full rotation. When the engine is at idle, which I can't do, it rattles on the clutch disk like it's going to tear the teeth off. Idle is taking the load off and slowing it to ab out 600 rpm to cool it out. It works, still clatters some.

Cat used a Hyatt straight roller bearing because it had to rotate all the way around when the clutch is open. The Cat transmission shaft seemed to be hardened material which is fine in the Hyatt bearing. I'm using cold-rolled shafting and I could picture those rollers wearing a groove for every one of those rollers in the Hyatt, and getting looser by degrees with every hour.

I ran the bronze bush for 10 years, probably 2500-3000 hours, after which I noticed it developing a wobble. I made a new bush, but it didn't take out all of the wobble. Possibly the shaft spigot wore unevenly because it cannot turn in the flywheel, and I had shorted the grease because I figured it didn't go anywhere with no spin. Anyway, I didn't get it back to true. That's my next job. The way I built it, it's a pretty simple teardown. I'm going to try to find a chunk of Aluminum Bronze this time. It's tougher than bearing bronze and machines beautifully. And we'll dial that shaft in with a big lathe and get the spigot into the center +/- 0.0001 or less. And make certain the center drilling is centered for future reference.

I spent some time looking for a PTO for a D311 engine, that's the industrial power unit. Nobody could even remember one coming through as junk, though a few are still in service