I ran my trusty Kohler 301 12 hp a bit low on oil, trashed the con rod. (My bad)It looks like the crank is ok but it has a decent buildup of galled aluminum on the one side. I could scrape it off but that would risk scratching the journal. Any bright ideas how to get the aluminum off without touching the journal? Maybe a few drops of a strong alkaline like lye???
Lye will do it. Much easier/faster if you can immerse it. Drop-by-drop would be tedious. The journal will not be affected, other than a very good degreasing.
Lye is good, but not a few drops. You'll need to cover it with solution.
If your patience is slim and if you want to do it at room temperature (a safe idea), you can use some Pequa drain cleaner. That's a straight 45% lye solution in water, and it's so concentrated that it's actually slightly viscous. 45% is dangerous to handle but it does the job. Dilute 50% with water if you're edgy about using a concentrated solution.
I've used 20% with success -- in fact, I've wrecked a few aluminum parts with it, trying to frost them. d8-) For reference, a 40% solution is 1 kg of lye to 1.5 liters (1.5 kg) of water. That 1 to 1-1/2 ratio is easy to remember.
My lye tank for small parts is a plastic Tide bottle cut in half. Don't use it with hot lye.
It contains some mild organic acids. They probably will have no harmful effect over a short time, but I wonder how long you can leave a steel crankshaft in them. Any idea?
This is the 12 hp Kohler K301 that is all cast iron. The output shaft bearing is a standard ball bearing with a 1.574" ID and around 4" OD. I've never seen such a massive bearing on a small engine. The flywheel end is the same 7/8" that most similar engines use for the drive end. It took two of us using a chain and sling to move if from the garage to the shop, feels like it weighs around 100 pounds.
Everything looks good inside except for a chip taken out of the lower cylinder, perhaps 3/4" square.
My local supplier has a piston, rings, and rod package for about $70. I'll check for taper and all that, good chance I'll bore it oversize. It's about due after all those years!
The engine was in a '64 Cub Cadet tractor that I've had since the '70's. About every 10 to 15 years I hone the bore and put new rings in. That little chore was scheduled for this fall, had one more 1/2 hour session before layup. Blew on startup.
Bridgeport with the vertical extension block. Standard boring head. Bottom of the block is flat, 12" high, 6" cylinder length. Not enough travel on the spindle, would need to use the knee. Mount the block on a tooling plate, clamp that down. Use a cylinder hone to get the surface finish I need.
I've tried this more than once with old Kohlers and not had much luck.
First one I did it right. I had it bored and the crank ground. I replaced every wear part (with Kohler brand not after market). Full rebuild. I ran it one month when it threw the counter balance gear through the side of the block. Moral of this lesson check the wear on the timing gear. Unfortunately it's made on the crankshaft and can't be replaced without a full crank (be sure your sitting when they qoute you the price). If you have some wear on the gear and have the counter balance gears my recommendation is to leave them out. It vibrates more but if the gear happens to get on top of the tooth and snaps the shaft like mine then it's not pretty.
I tried at least three other times after getting several of the same engines in a trade. None lasted more than a year or two (though I admit to cutting more corners on the later ones) . The last had the chip you talk about out of it and it ran about 1 1/2 years before the oil burning got bad enough I had to give it up.
I finally broke down and put a new 16HP Kohler on my old John Deere mower. It's been running great for 10 years now (though I've noticed it's been a little harder to start lately). That was another adventure since John Deere didn't use a standard Kohler engine but rather had a special oil pan to drop the engine lower over the front axle and had a smaller out put shaft than normal. The special engine was $1600 when the standard 16HP I replaced it with as $700.
Ed, I've soaked HSS taps in CLR for upto a week to remove aluminum stuck in the teeth. The surface of the steel turns black but the cutting edges are still sharp. Paul
Hmm. That black oxide may be a problem on a crankshaft. At the very least it would have to be removed.
Have you ever tried using a lye solution? It eats aluminum pretty fast and it doesn't hurt the steel.
Warm, 40% lye solution will actually bubble hydrogen gas off fairly violently as it eats the aluminum. But you don't need a 40% solution to do the job on cutting tools. A couple of tablespoons of lye in a cup of room-temp water will do it.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.