Crank damaged

Oak · #1 01-11-2010, 06:55 PM

I started working on my 126 and found that the pulley on the crank for the starter has lost the set screws and damaged the crank. The pulley is also damaged. It looks like the PO ran it this way for a long time and "wallered" out the pulley. What are my options at this point? Can the crank be sleeved or will it need replaced?

thenrie · #2 01-13-2010, 07:58 AM

If your engine needs an overhaul I would take the crank to a machinist and have it repaired. Otherwise, looking at the picture it really doesn't look too bad. I would try replacing the pulley and see if it is snug enough and doesn't rattle on the shaft. As long as the keyway is snug and the set screw is tight, you should be fine. Sometimes when this happens the crank keyway is damaged pretty badly and may need repair, but normally only the pulley's keyway is really bad. The pulley is softer than the crank steel, so it gets most of the damage. Always try the cheapest thing first. You're going to have to replace the pulley, anyway, so start there.

Oak · #3 01-13-2010, 08:20 PM

Thanks thenrie, The crank and keyway are a little damaged. When I move the pulley out to where the bearing mounts, it is not as sloppy as it is where the pulley should mount. I didn't mic it out yet and even thought about a thin layer of JB Weld but I don'y know how that would hold up under the stress and load it would have put on it. I'll try and find a new pulley and let you know how it goes. Thanks again

Rhoderman · #4 01-14-2010, 10:11 AM

Oak,
I'd highly recommend one of the dealers at the top of the forum for your pulley.
Rich at Patton Acres should be able to help you out. He might even have a decent crankshaft.
Or any of the others, I've only called Rich so far, and had excellent dealings with him.
Good Luck!

TBell · #5 01-14-2010, 10:45 AM

If you were a little closer I'd say bring it buy my shop. I have repaired cranks while installed in the motor. If there is a decent job shop near you with a horizontal boring mill they could set the block up and use a boring head to turn the crank, then rotate it 90 degrees and machine the keyway. I have done this many times on gas a diesel engines. No disassbly
Terry

thenrie · #6 01-14-2010, 11:30 AM

Just based on past experience, and looking at your photo, my bet is that if you put a new pulley on it and make sure the lock screw is snug, it will be fine. It's not as if it is a flywheel, with a lot of weight rotating around. At the very worst it will just beat up the new pulley after a few years of use. I would wait until I needed a rebuild to have that crank fixed (or replaced).

TBell · #7 01-14-2010, 11:40 AM

Another option wold be to go with the new pulley and a dose of loc-tite retainig compound. Let it sit for an hour or so and it will be like one piece. You'll need a bit of heat to remove it (propane torch) but thats the idea!
Terry

johncub7172 · #8 01-16-2010, 05:35 PM

OAK- it would be nice to see the pully. and the key slot on the crank. you could try some starter shim in the space between the crank and pully.that is a cheep fix. the loc-tight on the threads of the setscrews sounds solid. i believe a guy can darn near farmer-fix anything.

Oak · #9 01-17-2010, 04:15 PM

Here is what the slot for the key looks like. I will be ordering a pulley this week.

johncub7172 · #10 01-17-2010, 06:38 PM

thougth i'd post some crank damage in a better spot. k161 crank journal after connecting rod break. ih.cc. m71.