Engine/Transmission (1994 - 1998) P7100 internal advance?

[Fordiesel69]

While talking with a cummins shop nearby, I was inquiring about getting my timing set to solve a cold startup smoke and miss. He claimed that setting the base timing (more advanced) may not help the issue, and that there was a common problem within the p7100 timing advancment mechanism that would cause this white smoke and stumble only when cold. He was thinking it was in the governor cover or such. I really don;t know enough about these pumps to know what he was talking about. Did anyone ever have these symptoms?



In my reading, someone on here stated that there is no mechanical advance within the p7100.

 

[LMcCary]

timing advancement system??????

 

[Fordiesel69]

timing advancement system??????

As you accelerate, it will advance. I was under the impression the p7100 did not have one.

 

[LMcCary]

On the P pump, the rack determines the lenght of spray (Quanity) but not the start of the injection. An external timing device on some engines is used to change point of injection, but not our 5. 9 Cummins. Do a search on this site, much P pump info here.

 

[Vaughn MacKenzie]

The Cummins tech doesn't know what he's talking about. The P7100 has fixed timing. . . no advance at all based on engine RPM, cold start, etc. like some injection pumps do. So if your timing is set to 15 degrees then injection begins at 15* before TDC, whether at idle or max RPM or anything in between. Of course this is less than ideal since fuel always takes a few microseconds to begin burning once injected, so the higher the RPM the more delayed (retarded) the "combustion timing" is. That's why setting the timing on the p-pump is a compromise. . . you give up some in the bottom end to improve the top end.

The only exception with timing is the 215, there is something different about the plungers that set up a little timing advance but the change in timing is very minimal.

If you want a pump with good dynamic timing & cold start advance get an old VE pump off a First Gen

 

[bighammer]

Reminds me of my visit to our local bookstore Sunday. I was browsing and found a diesel book written by a "master mechanic" with an impressive sounding background. I thumbed thru it quickly and picture of familiar looking timing gears got my attention. The caption talked about the advantages of the CUMMINGS ISB gears over belts and thier indestructability. :-laf He put a "G" on Cummins and never did a KDP repair I'm guessing.