149 Winter Tear Down.

[Ambush]

A little better pic of the flywheel balancing set up. The time consuming part is waiting for the flywheel to stop. I give it a few slow spins in one direction and mark the high spots, then again in the opposite direction. Put a mark between those for the average then remove material opposite. Repeat until the stopping point is fairly random. You’ll never get it perfect, but so close it won’t shake. I’ll balanced the drive line as well. I’m hoping for an improvement in overall smoothness, but at least I’ll know where any vibration doesn’t come from.

[Ambush]

I got the rings filed to .012” and all the guts inside the case, shaft seals, valves in and gapped. Set the timing now while it’s easy and the point gap came in at .019”.

I have to pick up a few 3/8” Helicoils for the aluminum oil pan. The threads were pretty sloppy so I had deepened them and Loctite’ed in studs, which works ok but it’s a pain if you want to slide the engine back or forth.

[Ambush]

I got the oil pan Helicoil’ed. I always start taps in the drill press if possible to get them going in straight.

[Ambush]

When I bought this tractor five years ago, it was a smoker but not terrible and I decided to run it till winter as is and see what else cropped up. The rag joint was real bad so I changed that and while doing so found that the drive shaft didn’t line up good with the pump coupler. The shaft spigot and matching hole in the pump coupling were quite worn. I figured the motor was just misaligned. After putting the driveshaft back together, I loosened the four motor mounting bolts then retighten figuring it would “self locate”.

That winter I pulled the engine and rebuilt it and did a bunch of work. I make a new drive shaft and machined the coupling hole and new shaft aligning spigot to match. To my surprise the shaft still didn’t line up properly. It was obvious that the crank was not parallel to the hydraulic pump. The mounting holes were just not properly located. Time to fix that!

[Ambush]

I did some measuring and the holes were indeed not all square to the frame, one worse than the others. I decided to use the front left bolt hole as the reference from where to pivot the motor. A quick head calculation said I’d have to move the other hole on that side to the right 1/8”, the other two would need a bit more because they are further from the radius point.

I first made a bar to locate the exact direction each hole would have to be elongate, since all are different, and used that bar to scribe the material to be removed.

[Ambush]

I wanted tidy holes with no unnecessary slop. I had some blank circles left over from the loader project (pack rat) and a bearing with a metric bore that perfectly matched the drill size one over 3/8”. I made a jig that could be clamped over the hole and offset to remove the proper amount of material. The bearing turns with the bit and keeps it from moving back into th original hole. A freshly sharpened bit, some lub, a gentle hand and I had the three holes elongated neat and tidy. Seems like a lot of work, but it wasn’t. And the plate is 3/8” thick, so that would have been a lot of filing or many little grind stones. Metal burrs work but they bobble hard in small holes.

[Ambush]

The holes came out nice and crisp. I dropped the motor back in, put all four motor mount bolts in hand tight and checked the shaft to coupling alignment.
Nice to see it line up just right!

[West Valley G]

I wish I was your neighbor. So do you think the misalignment would
have been out of the factory that way?

Ken

[Ambush]

Ken, definitely. The guy welding in the mounting plates likely just got a bit careless. The original shaft was quite worn on the engine end as well.

[Ambush]

I bolted everything down, hooked up my “test” fuel tank and fired it up. Started quick and ran smooth and I set the low idle mixture and idle speed to 1,200 rpm. I ran it a few minutes, then I shut it down and had lunch while it cooled off. After retorquing the heads bolts I set the high speed rpm to 3,300 and adjusted the high speed mixture a little. I’ll do that better when I can put it under a bit of a load. This all took about ten minutes of revving up
and down. That’s it for running for now until I can actually load the engine. After this cool down I’ll retorque again. Then one more after a few hours of operation, when I change the oil.

I would say it definitely shakes less than it did, but maybe has more “fine” vibration. Not sure.

Of course I forgot to put on the small side shield that goes behind the carb, so that has to come off again. doh!