I am currently working on a piece of equipment that has a 12V Cummins with a P-Pump. It was brought to my attention that it "leaked oil very bad". Upon further investigation I found that when the engine is running there is a steady stream of oil seeping out just below the injector pump. This is my first time to remove an injector pump from a Cummins engine. I did lots of research on how to pull the pump and keep it all in time. However, after removing the pump I have several questions that I can't seem to find answers to.

It appears to me that the injector pump seals off with an O-ring in the timing housing instead of using a traditional gasket against the face of the housing?

I understand this pump is oil lubricated, where does the oil enter the pump at?

The "plate" on the pump that has the O-ring around it is held on with 4 torx screws. With the pump on a table I can grab the O-ring/plate and twist it a few degrees back and forth. The screws are tight but there seems to be "slop" in the bolt holes is this normal?

It seems that the pump is leaking because the timing housing has a grove in it where the O-ring should seat/seal. Is this common or is it because of the slop on the O-ring plate? Is there a sleeve kit to fix this or will I be forced to replace the timing cover?

Thanks, Forrest

 

Forrest,
Likely will need to pull the cam and replace the timing case. There are no sleeve kits available, I've ran into the issue previously. The pump is fed oil from a supply line in the side. I would send the pump out to be freshend up and note the cause for removal and ask the front plate be checked. This will prevent you or the shop from assuming liability for a 3k pump or future come backs. The one I was working with had a heavy groove from a previous install. Its always possible the timing case was cracked by the dowel pin. If that's the issue it could be leaking beside the pump on the block side. Have you pulled the timing cover?

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Thank you mysterync for your quick and accurate responce.

No, we didn't take the timing cover off. That was the original plan but we couldn't get ahold of a harmonic balancer puller.

After taking a second look and actually checking the 4 torx bolts wasn't tight on the front plate. I believe the leak was actually behind the front plate on a second smaller O-ring that seals the injector pump to the front plate. I would like to send the pump to a shop especially since the front plate houses the race to the front pump shaft bearing, but the pump will probably be put back on after we replace the O-rings and have time to "slap it back on".

This pump was removed to replace the solenoid about a year ago. You mentioned your have seen the grooving issue on the timing housing before from a bad install? We have a groove but its not horribly bad. We are going to go back with a new O-ring on the pump and hope for the best. Is there an incorrect way to install the pump or an alignment issue I should look out for when putting the pump back on?

 

The install issue was caused by a previous installer damaging the from lip of the pump. When he seated the pump a "knick" cut a ¼" groove in the case.
On another note, once removing the 4 damper bolts it should wobble right off unless it uses another style damper.
On pump reinstall install the pump pin, set the engine at exactly tdc and install. Make sure you clean the shaft and gear taper with brake clean and remove timing and tdc pin before torquing gear to 175ftlbs. In some cases equipment setups used a keyed pump gear in which case timing isn't a concern.
Glad I could help.
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