Harmonic Balancer Question

[ca90ss]

I recently bought a '64 C10 with a 6cyl. The engine has F0607CS stamped on the pad behind the distributor which from what I can find online looks like it's a 250 from a '67 chevelle. The problem I'm having is that the balancer spins about 1/16-1/8 turn freely on the crankshaft and wobbles quite a bit while running. Here's a picture of the balancer on the truck.

It's been several years since I've had a 6cyl but on all the v8's I've had there's always been a bolt with a large washer that holds the balancer on and I assume the 6cyl should be similar but there isn't a bolt on mine. So my questions are, should there be a bolt? I tried sticking a small screwdriver in the end of the crank and it only went about half an inch into it. Does that mean the bolt likely broke off? I'm having a hard time finding a replacement balancer at the local auto parts stores, does anyone have a part # for one that will fit? Thanks for the help.

[luvbowties]

Originally Posted by ca90ss

I recently bought a '64 C10 with a 6cyl. The engine has F0607CS stamped on the pad behind the distributor which from what I can find online looks like it's a 250 from a '67 chevelle. The problem I'm having is that the balancer spins about 1/16-1/8 turn freely on the crankshaft and wobbles quite a bit while running. Here's a picture of the balancer on the truck.

It's been several years since I've had a 6cyl but on all the v8's I've had there's always been a bolt with a large washer that holds the balancer on and I assume the 6cyl should be similar but there isn't a bolt on mine. So my questions are, should there be a bolt? I tried sticking a small screwdriver in the end of the crank and it only went about half an inch into it. Does that mean the bolt likely broke off? I'm having a hard time finding a replacement balancer at the local auto parts stores, does anyone have a part # for one that will fit? Thanks for the help.

I cannot answer your ???, but it may be a good idea to determine whether your crankshaft's key way is wallowed out before buying a har. bal. Hoping for you it's just the h-b you need.
sam

[61_FL_Apache]

Yes, there should be a bolt.. However, the crank is tapered on that end and should have a key way.. A replacement bolt may fix it.. I may worry about the wrong balancer is on there. The keyway may be missing.. I would try and remove it and inspect it first thing.. Post some pics if you can.

[awbrown]

I repair cranks for a living ,if it is moving at all ,it is roached!!! if you dont want to swap the crank out right now ,you can weld it solid but run water over the seal to keep it from burning up ,you may get some more time out of it .. I welded one in a plow truck on a 305 chevy and it was fine til I junked the engine .. does that mean this is a good idea..NO but if it is junk and you dont feel like changing the engine or crank it is a great idea... the 6 cylinder cranks are not tapped for a bolt most of the time , just like the old 283's were not tapped... there are not other fixes ,even putting a bolt in it , it will not stay tight , seen it tried before... if it was a high dollar crank it is no problem to weld up the snout and remachine the keyways and the OD...

[ca90ss]

Thanks for the suggestions, I'll yank it off and have a look when I get a chance and probably end up just welding it on. Only has to last until I can get the fuel problem sorted out on the Jag.