Okay long post warning.

So I’m helping my uncle rebuild the engine in a case 1840. The camshaft broke in half causing the failure. Anyways he did all the disassembly and replaced the cam. Now we are trying to figure out the fuel timing on this little Cummins 4-390. It’s a Delphi rotary pump.

Not knowing better he didn’t lock the pump prior to removing the old cam and the pump is in who knows what position as I’m sure the pump was spun. The book shows nothing on how to time the pump besides for pinning the cam at tdc and locking the pump then lining up marks on the pump body to the timing cover. But how does that do anything with the internal position of the pump?

Any walkthroughs on setting the timing? I believe this pump gear is keyed, and has letters on the gear face which corresponds to timing, but no idea which letter to set it on.

Again this isn’t a ve or p pump with the plunger to set timing.