I had no idea it would be so difficult to get a small engine crankshaft reground. I took my crankshaft to the local NAPA machine shop, the only place locally that does this sort of thing, and left in their capable hands.....
Over two months later, I finally got my crankshaft back. About a month into the waiting period, the guy said he called all his shops in Tacoma (WA) but nobody would touch such a small job, except for one place that quoted $280 (!!!) to do the work. But he said he was hopeful someone in Portland, OR, would be willing to do it. As the time dragged on, I was wondering if I'd ever see my crankshaft (and/or the new connecting rod I'd left with the crank) again. The Portland shop worked out and ten weeks after I dropped the stuff off I got my precious engine parts back home again. And my wallet was $135 lighter.
The old piston in the engine was looking rather sad so I sprung for a new one. I found a kit on ebay that contained a piston, rings and a complete gasket kit for a grand total of $72. A new 20-under connecting rod was $38, so grand total for everything was $245.
I used Hilton Hy-Per-Lube on some of the parts as an assembly lube because that stuff really stays put.
A short side note, when I was a kid we lived next door to the Hiltons (1968-1969). My dad got hooked on Hy-Per-Lube at that time and always had some on the shelf from then on. Their son Hal was my best friend for the two years we lived next to them. They had this cool demonstration device out in their carport that had two separate chambers with gears in them. One chamber had a bit of regular motor oil in it and the other had Hy-Per-Lube. You'd turn the crank and the gears would load up the oil, and when you stopped cranking, the regular oil would quickly run off the gears but the Hilton oil would stay put for quite a while. Hiltons bought a new Oldsmobile Toronado when we were neighbors, obviously a big deal to me since I still remember that. Hiltons also took me once to the hydroplane races at Lake Washington and we got to roam through the pits. Hal, if you ever run across this blog, this is John saying Hi. Ok, back to the rebuild.
I measured the ring gap in the cylinder and it was .020", right where it should be. Once the rings and connecting rod were on the piston, into the bore it all went, after a quick hone of the cylinder.
I sure hope I remember where all this stuff goes....
.... and this stuff.
The timing mark on the crankshaft isn't real obvious when you don't know what you're looking for. Usually it's a ground-off corner of a gear or punch marks on either side of a slot. The mark on this Kohler crankshaft is a cast-in slot that I thought I'd show in this next photo just in case someone wants to see what it looks like. The camshaft has a normal punch mark.
Cam, crank and piston are installed.
This next photo shows a broken mounting bolt in the cast iron oil pan. Someone at some point in the past broke the bolt off, and then tried to get the remnant out by cutting a slot in the stub but they were unsuccessful.
I used the MIG welder to weld a washer and nut to the broken bolt. It still wouldn't budge so I heated the corner of the pan with a torch.
That did the trick.
I don't have a valve spring compressor so I had to be creative in getting the valve spring keepers in place. My neighbor Dave happened to stop by and suggested I clamp the springs in the vise, then somehow constrain them in that position before installing them into the block. I elected to use zip ties, two per spring. They worked quite well. The photo below was after the springs and keepers were installed and only one zip tie remained to be pulled out, but it shows the concept. Thanks for the good idea Dave!
Once the springs and keepers were in I adjusted the valve lash to .008" for intake (.008 to .010 spec) and .018" for exhaust (.017 to .019 spec).
I was installing the driveshaft coupling on the rear pulley and the threads of one of the four screws stripped out in the die-cast pulley with practically no effort, so someone previously reefed a little too much on it. I fortunately had just purchased a Helicoil kit for my Kohler L600 generator just a couple days prior and it was the exact thread size I needed to fix this coupling.
First step is to drill the damaged hole to the size of the tap that comes in the kit. Then tap the hole.
Next install the Helicoil with the supplied tool.
Since I had an abundance of inserts, I elected to do all four holes.
The block is ready for the head to be put on.
I noticed there had been something in the cylinder in its past that really banged up the head and old piston. And if you notice the dark area on the right side of the head, it appears as though combustion gas has been leaking past the head gasket.
I took a file to the head sealing surface, then finished it off with some fine sandpaper and WD40.
Whoever rebuilt this engine the last time didn't take much care in some things. The gasket for the breather assembly is on crooked.
The fan shroud has a baffle that got whacked pretty good. Makes me wonder what hit it....
Looks better now:
This heat shield is held onto the cylinder head with two head bolts. You can see a large fatigue crack.
I took the MIG welder to the crack on the bottom side...
... then ground it smooth. I may also weld the top side of the crack.
The engine all ready to go back in the chassis.
Everything coming together.
The PTO (Power Take-Off) clutch on the front of the engine has a bearing that is held in place with an offset cam arrangement. Look closely at the bearing on the left and the locking collar on the right. They both have eccentric features that lock together when they're installed on the engine shaft. Slip both parts onto the shaft, then rotate the collar to lock the inner bearing race in place, then tighten a setscrew in the collar.
I spent the better part of an hour fiddling with the PTO to get it installed only to find out a bracket for the generator/starter needed to go on first. At that point I called it a night and went inside.
A couple days later I spent the better part of 20 minutes getting the PTO back off, just to get this generator bracket behind it. Then back on with the PTO.
I searched the garage looking for the small clamp for the throttle cable, but I just couldn't find it, so I had to make one.
It seems to work well enough.
Hmm, what's this? I rolled the tractor back a ways to get it ready to push out the door and what do I find on the floor but the throttle cable clamp....
Here she is in all her glory. Ready to fire up for the first time after the rebuild.
Below is a video:
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