ClassA4x4

On the face of the IP case (front of pump), there is a mark / indentation at 6 o'clock? What is that mark in relation to the keyway or TDC. Isn't TDC supposed to be when the keyway is at 5:30?

See that mark at the bottom of the round metal surface that surrounds the seal (not my pump)? That's actually at 6 o'clock because the pump tilts toward the driver side.

thrashingcows

I don't know for sure what that mark is for, but the pumps I've done I line the keyway up center line with that mark. I might have to turn the shaft just slightly one way or the other to get it to line up with the gear.

I think it's a "close enough" mark for lining up the pump to the gear.

93-12Smoke

I was told it's the timing mark put on after the pump is timed and locked

ClassA4x4

That mark looks like an original mark, not put on by servicing person. I've seen it in the same exact place on my pump and also in someone elses photo of his pump. The chisel mark on the housing is for sure put in there after the pump is timed and locked.

If that mark denotes tdc alignment with the keyway, then this Cummins video is in question. It specifically states tdc is at 5:30. Or maybe they mean the mark is at 5:30 when the pump top side of the triangle is perfectly horizontal, not as installed on its 3 mounting bolts ( note the pump is mounted in a way that it is tilted toward the driver side).

http://www.cumminsforum.com/forum/89...91-1993-a.html

93-12Smoke

I understand what you're saying. I think it means the 530 position with the top of the pump parallel to the floor.

93-12Smoke

To set the timing the pump needs to be held in a vise straight up and down so the 530 reference comes from that.

smooth89

Yeah, 4x4..that was the mark I noted in my post earlier. At the pump shop, they line the keyway up with that mark for TDC. Like Thrashing Cows mentioned, it may not be exact but it should be very close for mounting it back into the timing gear.

smooth89

Yeah, 4x4..that was the mark I noted in my post earlier. At the pump shop, they line the keyway up with that mark for TDC. Like Thrashing Cows mentioned, it may not be exact but it should be very close for mounting it back into the timing gear.

93-12Smoke

Smooth89, that only works if you pulled the motor to tdc as well.

ClassA4x4

I can't help thinking more about this and I finally figured it out.

That mark IS the alignment mark for the timing at tdc. The pump has more tilt to it than I had thought, so that when the IP is mounted that mark on the face of the pump is at 6:30 when facing it. That corresponds to the 5:30 on the gear drive looking at it from the back.

Qed!