Sheered crank timing gear key
 

Engine going back together this week but still have not figured what would cause the woodruff key to sheer, took all the valves with it. Cam spinns freely, distributer looks fine, bearring look fine but replacing anyway.

I hate that when it happens, such a small part causing so much pain. I have been there and know what you are going thru. I started using loctite and never had any more problems. My thinking loctite will soak up some of the worn clearences and reduce the shock loading. Minor heating will neccesetate the removal in the future if need be.

are running any kind of pump off the cam ?

Is it an SC engine or is it naturally aspitated? If it is supercharged, it should be double keyed. What type of balancer are you running?

Basically the woodruff key is only there for alignment by design, the clamp load of the bolt holds everything in place. My first thought is that the bolt may have been under torqued. Altough as some one asked did you add on a blower or another drivin component that put additional loads on the pully? this would be the second reason for failure.

Was the eninge stock factory built at time of failure or was rebuilt at some point - look at the history and you may come up with the anwser

I re-read the original post. I think he sheared off the timing gear not the balancer. It took the valves outs.

Sorry Ive been away from my computer.
NA 540, no cam driven pumps, was a new Eagle Crank when built, The gear afterwards will slid on and off but no cracks can be seen, I plan to get it manifluxed (sp). Tommorow I will
see if a new gear fits teighter. It has a Performance Products Damper, I may order a better one, also, I should have mention that the the windage tray bolted to the main caps was cracked in two. I had the pan off just 3 racing hours earlier and it was not cracked at that time. Seems like I may have some harmonic problem. I just ordered a new Harden Marine Pan with built in windage tray, it looks a lot more heavy duty.

Fast,
The gear should NOT slide all the way onto the crankshaft. If a new gear still slides all the way on, there is a problem with the crankshaft. There is a step on the crankshaft snout and the gear should be a press fit. You need to measure the diameter of the crankshaft where the gear sits. If you have a harmonic problem, the only way to properly fix it is to have the crankshaft balance checked. I would also suggest a different damper. ATI would be my choice.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Thanks Bill, their is a visible step on the crank and measures correct, the old gear slides on and off very easy by hand, I will check a new gear tomorrow, The Engine is being built by Monty Cline here in Richmond, I am just looking for ideas of what could have caused this, I know he is puzzled. Im running a Hays Aluminum Flywheel, mabe I should have all this rebalanced, we also plan to run a new cam with a 4-7 split, I think its called, should also help to run smoother.