I have spun the flywheel many times on this scrammy.The keyway is too small and it sheers . This problem keeps coming back.I've tried new flywheels and jig-a-boo weld(JB) i even welded the nut to a flywheel once(not good).But i keep sheering it. Have any of you race mod guys have this happen. Also the crank shaft isn't wore or chipped.Lastly do you guys or(Rick Ritter)think a larger keyway would help . I can machine a larger one.

Thanks
Matt
Team Bricktucky

 

I've not had this problem with mine, but I will be putting a race lightened flywheel on it as soon as Rick gets it done. I'll let you know how it does.

 

I've never had a problem! I've got two of them.

 

Hey Matt, you have a problem somewhere. A key will not keep a flywheel from shearing. As a matter of fact you can take out the key and not have problems as long as you get it tight enough. The keyways are machined for factory installation to keep the timing set, but they do not serve any purpose for holding the flywheel from spinning. The taper fit is what does it all. The primary clutch has no keyway, and all of the PVL aftermarket ignitions do not use a keyway, just the taper fit to hold in place. I have removed the keyway before on another application and advanced a flywheel a tiny bit with no key. You may have a tiny crack in the flywheel that only appears when it is tightened down, or the taper may have a problem, but a larger keyway wont fix the problem unless you use a harder key material. The only problem with that is you are basically covering up another problem by doing that.

 

Bubba is correct on this. The keyways and key are just there to locate the flywheel and crankshaft in the correct position for correct ignition timing. The wedging together of the tapers is what holds the flywheel in place. Here's a little trick you might try. First as Bubba said make sure there is not a crack in the flywheel hub. If it OK then check the crankshaft taper very carefully for burrs and remove them with a file. If this has happened as many times as you say it is very likely that either the taper in the flywheel or on the crankshaft or both may have some rough raised spots which will not allow the tapers to mate correctly. When you are pretty confident that you have both tapers smooth, then apply some fine valve lapping compound(available at most any automotive parts store) to the taper of the crankshaft without the key installed. Slip the flywheel on the crank and spin it back and forth. The valve lapping compound will smooth away small imperfections between the tapers. Remove and clean off the lapping compound and inspect the taper surfaces. This sometimes will make it apparent where there is a burr or high spot on one of the tapers which might need further work with the file. Repeat this process until you feel that both surfaces mate together correctly. Clean off all the lapping compound, install the flywheel key and flywheel, and torque the flywheel nut to the correct torque spec. Hope this helps. Let us know how it goes.

 

I think I found out what the problem is and was. The washer that is between the flywheel and the flywheel nut is the issue. Well, after tapping the flywheel on I noticed that the crank shaft sits out passed the flywheel ,so, if i tighend the nut and washer down it bottoms out on the crank shaft and does not push hard enough on the flywheel.For now i will try to use a washer that will make it around the shaft.I have two flywheels and both are the same outcome.

 

Good deal Matt. Sounds like you found your problem.

 

Go Matt!!!!