5000 crankshaft help

I have a 78 tooth crank that is bad but I have a 76 tooth crank that is good. If I change the balancer gears to match the 76 tooth crank will it work? 1965
5000 4.2 bore. Thanks for the information. Steve

I'm not aware that Ford ever changed the tooth count on the 4-cylinder cranks, only the width. Regardless, as long as you match like for like, I don't see an issue with it.

The 6X 5000 was 4.2 stroke 233 cid. 6Y 5000 was 4.4 stroke 256 cid. They changed angle of teeth on crank. Got into deal with someone putting 4.2 crank in 4.4 engine. Kept knocking balancer out.

(quoted from post at 23:07:48 08/06/20) The 6X 5000 was 4.2 stroke 233 cid. 6Y 5000 was 4.4 stroke 256 cid. They changed angle of teeth on crank. Got into deal with someone putting 4.2 crank in 4.4 engine. Kept knocking balancer out.

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My references have the 233 and 256 both with a 4.2 inch stroke. The 233 had a 4.2 inch bore and the 256 had a 4.4 inch bore.

I'll probably catch some flack for this But; When the first 5000s came out. we had several in our lease fleet, for pulling pea combines. Replacement balancers weren't available, so the owner decided to see what happened if he ran them without a balancer, didn't seem to affect the operation of the tractor, so he left them out, if they went bad. He was a little bit of a rebel.

(quoted from post at 13:39:48 08/06/20) I have a 78 tooth crank that is bad but I have a 76 tooth crank that is good. If I change the balancer gears to match the 76 tooth crank will it work? 1965
5000 4.2 bore. Thanks for the information. Steve

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The balancer weights need to turn at twice crankshaft speed. Therefore, if your crankshaft has 78 teeth the balancers need to have 39 teeth. If the crankshaft has 76 teeth then the balancers need to have 38 teeth. The balancers may be different for the different stroke chankshafts - I don't know and can not comment.

The balancers act on what are called secondary forces. The unbalance forces of the pistons change of direction at TDC and BDC are called primary unbalance forces. The weights on the crankshaft act on the primary forces.

The secondary forces have to due with the acceleration difference between the piston pairs at TDC and BDC. Secondary forces are much less than the primary forces and many engines do not include the balancers.

Since the secondary forces are less and many engines do not use them I suspect you could get away without them. I have heard of people doing it however, I have no experience personally! Last year my brother overhauled his 7000 (?) and found the balancers had no timing marks. We considered leaving them out however, after some head scraching we determined how to time them and left them in.