Valves messed up from crank????

Callmewhitexr7

Registered User
Ok the crank on my Sc is broke I've gotten the parts together to rebuild the motor and so im going to start on it this weekend hopefully. My ? is the motor still turns over but the balancer quits spinning at a certain point and then starts to spin again at a different point. This is the crank right, and also could my valves be messed up since the motors still spinning yet the balancers not? Cause the balancer and the timing gears run off of the same keyway.... I'm hoping they arent messed up or anything but does anyone think they will be? Thanks for the help.



NICK
 
The balancer is attached to the crankshaft. If the balancer stops spinning that means it's rotating on the end of the crankshaft. Did you put a new key in the keyway before installing the balancer?

That should be a interference fit anyway and the balancer shouldn't sit still if the crank is turning. It could be that your balancer has stretched, or the previous crank it was on was slightly larger on the snout.
 
Ok i need to better explain. At a certain point in the revolution of the crank the balancer pulls in toward the motor and quits spinning. when it does this it makes a knock sound. then at another point the balancer comes back out and spins again. I'm thinking the crank is broken somewhere in there. but if the motor is still cranking over yet the balancer and the bolt arent I'd think it would mess up my valves right, since the cams not moving either. Thats what my ? pretty much was.. I guess I should have stated it more clearly.. Sorry...


NICK
 
O.k., yes your crank is shot. You may as well pull the motor and you can inspect the valves when you pull the heads. They may or may not be hurt depending on where things died at. The knock is likely part of the crankshaft damaging the main bearings. So stop turning the motor over.
 
Ok well the balancer does turn tho so things are still moving in the upper part of the motor. I've got a new crank and bearings and everything for it, i'm just wondering if the valves are messed up, I guess one could only guess I'll just have to wait till I get the heads off and see. Hopefully not.. Well thanks again


NICK
 
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