630 Knock

This is LONG......

After reading & hearing about all these 630's with main bearing issue's after the crank case gets washed
out from gasoline & fuel shut off diaphragm failure. Which has happened twice to this tractor in the last
10 years. But it was caught rather quickly, because I watch things like this & check oil's be for using any
tractor. I've noticed HIGHER than normal oil pressure on this machine which made a lite come on in my brain.
Thinking the O ring seals were swelling shut & transmission had been making oil. This tractor also has a knock
with the PTO disengaged but quiet when the floor shifter is engaged. Having 10 of these 2 cylinders on the farm
we just haven't used the 630 too much thinking something was wrong & having the time to go over it.

I started by ordering gaskets & seals 1st , clutch kit. Tore the tractor down with 1st reduction cover off,
clutch driver on the crank, Made a device to hold the cam shaft in place started the engine to see where the engine
oil is coming from, sure enough the main bearing quill had a track of oil at the main case. Check main bearing
clearance OK on both side.. Replace'd every thing & check for leaks OK.. Oring were swelled some but still had a 3/16
hole threw them but RH side the oring was cracked. LH side wasn't cracked & not leaking but now replaced.

Now for the noise/knock... The only thing turning is the PTO drive gear off the crank shaft. After checking/study
measuring & not having all the nessasary tools required in depth. At some point in time the upper R-20178R clutch
fork spring Broke & somehow a piece went threw the crank drive gear & the constant PTO gear (I think)?? NO Damage marks
on either gear. But after spinning the PTO gear I noticed it was slightly out of balance. ( Maybe they all are?) Bearings
are perfect, But I got new ones & tried it, knock is still there. When the PTO floor shifter is disengaged. Engaged
perfect or as perfect as a 2 cylinder can be.. I'm getting bother upper & lower new springs from a dealer in Iowa. Ob new stock.
By added the Load to the PTO gear Noise is GONE.

I chucked the gear up in our brake lathe at work using a dial indictor checked each tooth & I found it's egg shaped ?
Where I started to check @ .0000 it goes to .0017 & at one point -.0004. I've found a used gear & it's not a lot of money
plan to try it, I am thinking I should also do the crank drive gear too? But again I can see nothing wrong with it. I am
unsure it's even possible to egg shape a gear this size, I know I wasn't running it when it happened or if it even happened.
It never use to knock but now it does. Also the oil pressure is lower not pegged, more desirable once it has all new seals.

Has anyone else ever seen this or had this issue?

Sorry this is Long but My Mind is full of doudt....

Interesting story - keep us posted on what you find out.

I replaced the crankshaft seals and other soft parts on my 630 last winter. My upper clutch fork spring was also broken, and the pieces that I found in the FRG cover indicated that it had gone through the gears on the way down. I couldn't find any damage to the gears, but by visual inspection only. No PTO related noise either. I've had the tractor for 39 years, and have been mostly the sole operator, but I have never noticed any noise that I would think the spring would make as it tangled with the gear train.

This tractor has been on the farm since 1962. It's 59 model & still looks & runs great. Was repainted by me in 1982 @ that time
all the tires were replaced, I had it sand blasted when the tires were off. Went with 45 over pistons & new exhaust valves, rod bearings.
New tach & cable & what ever else it needed at the time. Now showing 9634 hours & another set of rear tires since then. Still has 115 pounds
compression at cranking speed.

When I removed the flywheel last week it's I'm sure the 1st time it had ever been off. Over all it's been a trouble free machine over the years.
I have everything washed out & drained except the PTO oil & hydraulic, which I plan to go threw & replace what ever is needed as I am working my way to
the back end.. This time it's getting a new battery box & rebuild the float ride seat, replacing the PTO seals & going threw the PTO Clutch in the rear
housing. About a month ago I went threw one of our 60's doing the same thing, started at the frt wheels & worked my way back. Last year was the 2750
4x4 tractor, that took me a 3 months. That tractor has over 13K hours. About the time I get one done, I hafta start on another once I check the log
books I keep on each tractor.

I also double checked myself, by re-chucking the gear rotating it in the lathe thinking I didn't have it centered. Using another color of paint
& the end result was the same. So now I have a gear with white & orange paint on any tooth showing above .0000 which is about 1/2 of them. All 3
rivets are in place, but the outer gear IS NOT centered on the cast insert. It runs .0005 out.

How the heck is HALF A THOUSANDTH relevant to that gear in any stretch of the imagination ?!

I'm more like a idiot than a machinist.. .04 to .17

Installed a used gear from a black dash 620,reassembled Noise/knock is Gone......