Crank Timing Gear

First, straight from the front, I'm no mechanical expert. Much of what I know I've learned from working on my TO30 and from reading it's manuals or this site.

Today I had the front end apart to get the pivot pin and bushing out. Bushing was shot and is ordered.

While apart I also removed the timing cover to check whether I could see anything that might make a ticking noise I've tentatively narrowed to the timing gear area.

The crank timing gear is not set back quite as far as the cam gear. Behind the timing gear is a (not circular, anymore at least) piece that it catching the cam gear. It this what the manual calls the thrust plate?

From the pictures you can see the cam gear has crushed "teeth" into it over the years of running. That piece is also not tight. Poking at it with a screwdriver it will rotate somewhat freely. I cannot feel any play in the crankshaft, but the manual suggests shims here control crankshaft end play. The piece is not a circle. For about 1/3 of the circumference it is not visible, for the other 2/3 it is visible and catching the cam gear teeth.

Questions: 1) Should the gears be in exact alignment? 2) Should this piece (whatever it's proper name) be loose or fully pressed tight? 3) Could the gear be pushed back farther to bring it into alignment and also push the piece out of the way of the cam gear? If it could be pushed back further, what is the technique? 5) Is this a problem, and if so what is the best solution?

This may not be the source of my tick, but turning it by hand it does seem to catch rhythmically each revolution.

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Whatever that is the red arrow points to is not supposed to be there.

The "thrust plate" is referring to a plate behind the cam gear. It positions the cam/gear assy. It is probably OK, you can see it through some holes in the cam gear once you remove the governor.

You'll need to pull the crank gear and remove the spacer, everything should line up then. There is also a sheet metal oil slinger that goes in front of the crank gear. Was it there?
 
Been a year since I had one apart like this but- 'I think' this chewed up stuff is the shims, they might be- have been loose, and might be the source of the rattling front pulley, scuff marks and end up doing worse than make noise, so will the dying governor ball keeper, new governors are over 140 bucks, I suppose you can buy new shims on here too, but while it is apart this far, pull off this and only fix whatever's broke!
 
Rethinking this... The manual I looked at is for a later model, yours may have some shims there. If the back side of the crank gear is flat, it needs shims. If it has a shoulder, it does not need shims.

Something else to check is the end play on the crank thrust bearing. Be sure you have some free travel on the clutch, you may want to loosen the pedal and get a little extra just to be sure. Then push or pry back on the crankshaft to see how far it will go back. My book calls for .002-.006 end play, It will probably be more than that, and that's ok, but not excessive.
 
(quoted from post at 23:17:58 03/12/14) Rethinking this... The manual I looked at is for a later model, yours may have some shims there. If the back side of the crank gear is flat, it needs shims. If it has a shoulder, it does not need shims.

Something else to check is the end play on the crank thrust bearing. Be sure you have some free travel on the clutch, you may want to loosen the pedal and get a little extra just to be sure. Then push or pry back on the crankshaft to see how far it will go back. My book calls for .002-.006 end play, It will probably be more than that, and that's ok, but not excessive.

Steve:

That makes more sense. Here's the diagram I was looking at from my manual. The top is a TO30. I had thought number 4 was the damaged piece I can see, but I'm not sure. It shouldn't hit the cam gear, I'm nearly sure.

So far I'm hearing I need to get that gear off and see what I've got behind it. Maybe remove a shim if needed to get it to go back on flush with the cam gear. Is it possible it was just never installed far enough back when some previous owner had it apart?

You mention "free travel on the clutch". I'm not clear on the meaning of this. But I was wondering how to asses end play. I figured it should have some (it is an old tractor) but so far I haven't got the shaft to move, although I wasn't sure how much to pry.

You asked about the slinger. It was there.

It's looks like tomorrow I'll head out to get a gear puller and something to press the gear back on.

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OK, now were on the same page. Yes, #4 is the part
the cam gear is chewing on. Part #16 is worn, and
has let the crank move forward.

The crank will have to be removed to replace it.
Good chance the thrust surface of the crank will
be bad also.

The release bearing on the clutch may be applying
forward pressure on the crank assy. You need to
back off the adjustment to get a true feel of the
end play of the crank.

Depending on how much you use the tractor, you
will probably opt to remove the shim and move the
crank gear back to stop the interference of the
cam gear and the thrust plate. Not a good fix, but
your looking at major tear down to fix it right.
 
If #16 is worn but to the point crank or block surfaces are damaged couldn't you break #16 out of there and use a flanged bearing like TO20??
If that would not work how about using Z134-Z145 mains that take trust off the center main.
That has been discussed here but not certain if it works or not even tho I see at least one vendor that sells one main bearing set for Z120-129-134-145.
 
You know, I thought about that... Subing a TO20 front bearing. Never tried but looks like a maybe. Don't think a 134/145 center thrust would work, no thrust surface on the center journal of the crank.

Also wondering if removing the shim so the crank gear will go further back will allow the pulley to still tighten down. Might need to shim the front of the gear... Where does it all stop! By now I would be talking myself into pulling it out and fixing it right.

And... what are the consequences of running it with the crank shifted that far forward? What else is miss aligning? Rods binding? Starter drive hitting the front of the flywheel?

I hate guessing and short cuts!
 
I never tried it either but was sitting here thinking that it might work. After 60 years on these tractors you would think some one has been down this road before. I would not want the crank shifted forward more than a few thousands.
 
Don't forget that the TO-30 originally used a fiber thrust washer which was known to fail after several years. somebody may have replaced yours at some point in time with an aftermarket one or they may have had one fabricated at a machine shop. Flanged main bearings weren't available for a long time but Sparex nows shows them to be available.
 
Jeremy, just to be straight what we're dealing with, the crank thrust bearing has failed completely. The crank has shifted forward way beyond where it's supposed to be.

It is still running that way, what it will hurt? Don't know, but it can't be good. It's up to you if you want to go in and repair it, time and money, or keep running it this way and possibly do more damage.

If you decide to just remove the shims and push the cam gear back, be aware the goal here is not to just line up the gears. That's not critical, what is critical is to maintain "some" end thrust clearance on the crankshaft. If you take out the entire shim, when you bolt the pulley back on and push the gear back, it could remove all the clearance and lock up the crank, not good! It will probably need some shim, as in having to make one the proper thickness.

Also, after you get the clearance set, check the length of the end of the crankshaft. From the front gear to the end of the crank must be less than the length of the inside of the front pulley plus the slinger. If it's too long the pulley won't tighten down against the crank gear.
 
Yes! Flanged main bearing would be the way to go.
Drop the pan, remove the main cap, break out the old thrust washer, if it's still there, roll in the flanged bearing. Might not be perfect, but better than it is now!

Thanks.
 
Steve (and everyone else):

I thank you for your time and helpful comments. I pulled the gear off this morning and if possibly I'd like your help interpreting the results.

The piece that was getting chewed up was clearly home made by someone sometime in the past. (See picture, this is after I spent a lot of time cleaning it off and smoothing it out). At first I assumed that someone tried to make a home made thrust plate (#4). However, behind it is what looks to me like the actual thrust plate. (See photo). Behind the true thrust plate (or whatever it is) is the bonzish colored piece which I assume to be #2, the thrust washer. It has the pins in it as in the diagram. Behind it are several shims also as pictured in the diagram.

So, when I took the home made piece off and gently press the gear back into place it aligns perfectly with the cam gear, it cuts out the end play (thanks for reminding me I must make sure I leave some, the manual says .003 to .007). And the crank pulley is still longer than the end of the crank as you noted it needs to be to be.

Why would someone have made this piece and put it in there. And is there any chance I can just leave it out and run it from here on? It has to be better than it was (gears not hitting that piece, end play reduced) even if it's not ideal. I want to read more about the flanged bearing option, but until then?


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The TO-30 had both an inner and outer thrust washer and shims to control the endplay. It looks like somebody didn't have shims or was too cheap to buy any and used a homemade one. I would just get the proper thrust washers and shims and see how if you can get the end play set right.
 
Even if that homemade shim did work it looks like its in the wrong order. The order from the block should be inner thrust washer, shims,outer thrust washer,thrust plate, then the gear
 
At this point I think I would put the gear on without the shim, put the pulley and slinger on without the cover and tighten the front bolt. Then check to see how things line up and much end play you have.

I suspect there is a problem with the thrust bearing surface on the crank, as in it's worn beyond limits. Most likely it has gotten worse since the homemade shim was installed. If it had a fiber washer, it may be completely gone. But, if they were trying to tighten the end play, that shim would have had no effect, way I see it.??
To reduce the end play you add shims behind #2. That will work if it's somewhere near tolerance, not if it's 1/8 inch or so.

Still, I would try and see, it could be OK...
 

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