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+--- Thread: Is this normal? (/showthread.php?tid=6998)
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RE: Is this normal? - JimT - 02-05-2021
Ok, maybe I should clarify what I mean when I suggest periodic inspection.
First, only the pump head should be removed from the pump cam housing. Unless you are troubleshooting a specific problem there's no need to remove the pump actuator from the pump head. Because of this the only places where the fuel system is exposed to contamination are at the fuel line connections to the pump head and actuator. These should be cleaned prior to removal and plugged according to cummins procedures.
Second, unless you have good reason you shouldn't remove the barrels from the pump head. Simply removing the springs should be sufficient to inspect the point where the plunger makes contact for signs of damage.
Third, the main area of concern related to pump wear and failure (for pumps with steel plungers) is within the pump cam housing. You want to remove the tappets and inspect the cam, tappets and bore for signs of damage or excessive wear. This is where the destructive metal debris comes from and is lubricated by engine oil. I don't see this as being any more risky then opening up the valve cover to inspect the top end or adjust the valves. Of course you should keep the area as clean as possible.
In these steps, and the reverse reinstallation, the only exposure to the fuel system is through the fuel lines that need to be disconnected (there are 3, one on the rear of the actuator, one on top of the pump head and one on the front of the pump head).
I think these steps are safe enough to perform once or twice during the 400,000 mile service life that we promote for these pump heads. Remember, the fuel pump (on cm2250 and cm2350) gets oil supplied to it from the front gear housing, so any dirt or debris present or introduced there will potentially find its way into the fuel pump cam as well.
I understand people's concerns about contaminating the fuel system. Unless you have cause, I wouldn't suggest removing the pump actuator from the head. The only real reason for that would be to test the check valves by applying shop air to extend the plungers.
Hope this helps clarify my opinion and statements.