    
Bill Davis (Nvbigblue)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 23, 2005 - 10:30 pm: | 
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Dave,
I have two methods I use to keep crankshafts from turning.
#1 . Use a strap wrench. If you're not familiar with this type of tool, it has a handle about 12 to 16 inches long and a heavy nylon strap about 1 inch wide attached to one end. You wrap the strap around the item you're trying to hold, pass the free end back through the tool and when you apply pressure to the handle, the free end is pinched between the tool and what you're holding. This effectively tightens the strap and keeps the item from turning. You should be able to pick one up at a NAPA or other auto parts/tool store. I've found this tool works a LOT better at holding crankshafts and pulleys than other methods such as sticking a screwdriver between rotating parts, or trying to "jam" the flywheel. I've broken teeth off of flywheels doing this.
#2. Use rope. I know this sounds funny but it works rather well. Buy some small cotton rope about 1/4 to 5/16" in diameter (25' will be enough for a small engine). Remove your spark plugs. Place your finger or thumb over one of the spark plug holes, and verrrry slowly turn the clutch (DO THIS BY HAND ONLY!) in it's normal direction of travel. When you feel suction on your finger, the piston is on it's intake stroke. As you continue to turn the clutch, you should feel it reach the bottom of the intake stroke and start back up on the compression stroke.....STOP NOW!! The idea is to get the piston to the bottom of the cylinder on the intake stroke, so that when it starts back up, both valves will be closed. If they aren't...this method can break valves. Now...with the piston near the bottom of the cylinder, take your new rope and feed it into the cylinder through the spark plug hole (NOTE: Your rope should be long enough to fill the cylinder and still be hanging out!! Don't shove all the rope down the hole!! You need to be able to pull it back out!) Push as much as you can in (I sometimes have to use a small screwdriver to help it in). When you can't get anymore in, turn the clutch some more. What should happen is now the cylinder is full of rope and it will get compressed between the piston and the head, and keep the piston from coming all the way to the top. TADA!!! You should now be able to remove your bolt from the end of the crankshaft. To reinstall the bolt you will have to put the rope in after spinning the crank backwards until you feel compression. Regardless of direction, the most important thing is to make sure the valves will be closed....we don't want to snap the stems! I've used both methods with success. Just be careful and work safe.
Regards,
Bill Davis |
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