Bolt holding clutch on crankshaft keeps loosening
- Thread starter chuggins08
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chuggins08
New member
i have the bolt that says what the crankshaft is threaded for. I am putting enough loctite to get all the threads. By wiggly, I mean i can move the bolt up, down, and to the sides. but the farther I go into the shaft, the more stable the bolt gets. It is weird. The bolt does not come loose while I have it on the stands, only when I actually get in and drive it. I got a longer bolt this morning; so i am going to take it for a test drive in a little while.
chuggins08
New member
Just took it for a test drive and the bolt did not loosen itself, but the chain came off. I am thinking the chain is too loose and its jumping off the sprocket.
chuggins08
New member
Well I loosened the engine mount bolts and moved it forward to tighten up the chain. Took it for another test drive a few minutes ago and the bolt loosened up on me again. This time it lasted about 30 yards...
you're sure the set screws you used as key are still intact?
maybe they're sheared off.
'sid
maybe they're sheared off.
'sid
OzFab
Well-known member
Something is drastically wrong here... Either you have the wrong size bolt or the clutch is not on the shaft far enough. Remove only the bolt from the end of the shaft, take a pic & post it...
If possible, also take a vid of the "wiggly" bolt movement...
If possible, also take a vid of the "wiggly" bolt movement...
fowler
New member
here is a quick video of how a bolt should sit in the threads
i dont know why its gone into portrait but anyhow
http://www.youtube.com/watch?v=ZlJ0CP6maY0&feature=youtu.be
i dont know why its gone into portrait but anyhow
http://www.youtube.com/watch?v=ZlJ0CP6maY0&feature=youtu.be
Use a battery powered impact gun. Not a pipe wrench. You also need to have the "guts" completely under the drum so space the crank with spacers.
Are you sure when you tighten the bolt that the drum still spins free? If the drum spins along with the crank you have an issue with the mandrel and its locking together and just spinning the bolt right out as you move forward. We need more pics of the clutch and the way you have it put together to make sure you have all the parts assembled right.
Are you sure when you tighten the bolt that the drum still spins free? If the drum spins along with the crank you have an issue with the mandrel and its locking together and just spinning the bolt right out as you move forward. We need more pics of the clutch and the way you have it put together to make sure you have all the parts assembled right.
mckutzy
Well-known member
With all this effort, How much would it be for a new crank shaft.
For the most part it sounds/looks like the threads are bunged up some how and that what is the problem.
I cant say re-tap the threads cause its hardened, so a new shaft might be in order.
For the most part it sounds/looks like the threads are bunged up some how and that what is the problem.
I cant say re-tap the threads cause its hardened, so a new shaft might be in order.
You could retap. Many people have drilled and tapped shafts. It is a common practice
mckutzy
Well-known member
really... ok. Not that hardened??
OP why not re-tap the threads then? or get a shop to do it for you.
OP why not re-tap the threads then? or get a shop to do it for you.
You can just think of how many people have cut keyways and turned their shafts down on lathes. Not too difficult
mckutzy
Well-known member
I get that, but grinders and carbide tooling are harder than case or through hardening of most shaft steel.
I have worked on electric motor shafts but I would think that an internal combustion engine crank shaft would have been more tougher, well none the less good to know.
I have worked on electric motor shafts but I would think that an internal combustion engine crank shaft would have been more tougher, well none the less good to know.
OzFab
Well-known member
Yes, the crankshaft is hardened steel but, any decent tap is carbide, much harder than hardened steel
When I turned down my crankshaft, HSS wouldn't touch it but a carbide bit ate it... (it wasn't much good after though
)
Having said all that, Chuggins, try a M10 bolt, just to rule it out...
When I turned down my crankshaft, HSS wouldn't touch it but a carbide bit ate it... (it wasn't much good after though
)Having said all that, Chuggins, try a M10 bolt, just to rule it out...
philip metzner
Member
I thing there is something wrong here that we are assuming is right because it is considered common knowledge. Things like, the clutch doesnt fit the shaft right, or sprockets are out of alignment, or engine is crooked, or clutch is jammed on a tapered crank, ect. What happens if the bolt comes loose?? If everything is right and the set screws are tight, the answer should be nothing. If the clutch is trying to walk off the shaft something is wrong. Why does the clutch drum have marks on it from the chain pins? Why did the chain come off the one time the bolt stayed in?
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