Turn out to be the governor, was missing 8 out of 10 ****. When the only 2 dropped into the pan the cam was allowed to float horizontally which changed to mesh of the cam gear and the distributor gear. Engine is now undergoing a total rebuild.

Thanks, I will start with the pump. Just what I want to do, climb under a grungy old forklift but better that removing the counterweight etc to remove the cam.

Well, I'd probably start by checking the oil-pump out. Broken teeth, excessive wear or debris can shear that pin easily.
A screwed pump would also give you the vibrations.
Short of that, pull the camshaft and check the gears and the bearings.
I honestly can't think of how worn cam bearings would break the pins, but if it's not the oil pump then we're just going to have to eliminate everything else.
A worn cam bearing or damaged distributor gear could give you your vibrations though...

The forklift is a Hyster H30F with a G193 Continental L4 engine. I do not have any serial #s at this time.

We'll need some more info.
What is the model & s/n of the unit, and what engine is it?

From what you've allready been through, you'd better check the cam and the timing chain/belt and tensioner.

But we will need more info to give you a better idea of what to look for.