630 belt pulley/clutch trouble

old bones

Working on the 630 basket case I got a couple months ago. Belt pulley was in the basket when I got it. Ordered 2 new clutch facings, clutch drive disc, clutch
disc with bonded linings, clutch springs, and t-bolt nuts. The old clutch drive disc that was in the basket was loose on the crank, and slid on the crank 1/8+
inch past the end of the crank.
I cleaned the t-bolts, dogs, and toggles before putting it back together. Then I hung the belt pulley back on the crankshaft, put a clutch facing in, then put
the new clutch drive disc on. It was out 1/4 inch from the end of the crank- good news.? I propped the flywheel so it wouldn't turn, then put the bolt and
washer on the outside of the drive disc and tightened it to 175 ft lbs. Took the prop off the flywheel, and crank is solid as a rock. Can't turn engine with
flywheel or from belt pulley side.
I took the drive disc back off, and see that it pulled further on the crank, but still out past the crank by a good 1/16. I can turn engine over with flywheel
and belt pulley.
Something is binding, but what? Then, I wonder if whatever is binding up is holding the driving disc out past the crank, and not the taper like it's supposed
Not sure what to check. Any help would be appreciated.
Thank you.
One thought is maybe the disc behind the clutch driver came dislodged from the machined surface of the pulley and is now pushing the pulley tight against something.

Any chance did you compare the old clutch driver to the new clutch driver?? Maybe maybe the new one is too thick and it's pushing up against the disc and belt pulley??

Next I'd try slowly tightening up the clutch driver again and turn the pulley at the same time and maybe you can feel what's starting to bind. Take a look inside the clutch fork opening while you're tightening the driver as well may you can see something happening in there.

This post was edited by 620 John on 11/30/2023 at 05:09 pm.
I checked the disc behind the driving disc- it was in place.

I checked the disc drivers, old and new- both the same thickness.

I'll have to do the tighten-turn-tighten-turn thing tomorrow. I looked in the clutch fork opening, and it looked like the gear on the back of the belt pulley was
against the gear on the crank, but I'll have to take a closer look tomorrow.

Thank you.
When driver is installed and bolt is torqued, is there end to end free play / movement of clutch pully on the crankshaft? There should be allot and pulley should also spin free. If not, remove the clutch pulley and inspect drive pulley gear that it has not moved away from pulley. It is hard to detect because you cannot see the gear shoulder gap under the actuator. Years of snapping the clutch in and out can gradually move gear off pulley. To correct, it can be simply be pressed back on in a press but, MAKE SURE you block the center of pulley when pressing gear back on as you can blow / break the cast pulley center stem. It does fit tight and will pull off hard to remove if you desire to remove it and will take some power to press it back on. Seen this on many later model two cylinder tractors. DW
No, there is no free play/movement of the belt pulley. Won't spin until the drive disc is loosened up. Have not had time yet today to look at it further. It just acts like the whole pulley assembly slides too far onto the crank. Will post back when I look at it this evening or tomorrow. Thanks.
That's right the pulley assembly is too wide when drive gear works it way off pulley making it too wide / long for distance between crankshaft live gear and clutch driver. We need to Narrow the pulley assembly by pushing pulley gear back onto pulley.
Took it apart and put the pulley, clutch facing, and drive disc back on. The pulley was rubbing on something as I tightened it. There was some dried grease/oil/dirt on the dust shield, by the pulley shield. Chiseled that off and tried again. Got the bolt torqued to 175, and the pulley turns, but the clutch is engaged pretty solid (turning the engine over), with just the one clutch facing between the pulley and the drive disc. Couldn't budge it loose. Tried setting brakes and turning the pulley, but it was solid.

Took it apart again and put in the old clutch facing behind the drive disc and tightened it up. The facing drags a little, but the clutch pulley spins like it should. I measured the old facing and the new facing, and the new one is about .030 thicker.

The driving disc is still out past the end of the crank, but only by .050, so it's pretty close to flush. Not good. I guess I'll probably get some individual feeler gauge blades from the SnapOn guy and use them for shims in the tapers. Don't know of any other way to get the drive disc further out on the crank splines. I'm thinking that should get the drive disc out to 1/4, and give me some more room for the new thicker clutch facings (I hope).

If there's anything else I can do, please throw it out there. I'm open to suggestions. If anyone knows where to get a drive disc made for worn crank splines, Please let me know.

It use to be Denglers Tractor- Ohio.. They had .030 undersize splines on the clutch driver.. But they must be out-of- business? Can try, 513-423-4000- Middletown ,Ohio..

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