Re: Outside counterweights

On the K-27's, where counter weight space is limited by diameter, not the width between the frames, the counterweights are external, although I believe the main driver has an interal counter balance as well.

The K-28's have internal counterbalances on drivers 1, 2 & 4 and possibly all drivers, but the main driver does have an outside counterbalance because of the extra weight of the main rod.

The K-36's and K-37's are bigger, heavier engines and have external counterbalances, possibly due to lack of space in the drivers themselves, but possibly also to get the rod counterbalancing as close to the rods themselves as possible.

Michael Allen