I am in the middle of adjusting my pump timing. The truck was originally and automatic but is now a NV4500. It still has the 180 HP pump in it. The CPL is 2022. The engine plate states that it meets US EPA and California specs.

The factory manual gives specs for 49 state automatic, 49 state manual and California w/EGR. Mine does not have an EGR. Do I have the proper timing specs with the EGR equipped engine?

It appears that I have 4.65mm of lift. Should I be looking for 4.8mm of lift for a timing spec of 15.5mm?

As far as I know, this engine has never been touched but it appears from my available specs that it is already at 14.5mm. If this is correct, will advancing it one more degree help?

Thanks in advance
Don

 

The pump is for the 49 state automatic, so use the table for that engine to determine your plunger lift.

4.6 mm plunger lift will give you 15 degrees, 4.7 mm is 15.5 degrees, and 4.8 mm will give you 16 degrees.

The lead in that pump is such that you can safely run to 17 degrees, or 5 mm on a standard transmission as long as you are not starting out pulling really heavy loads.

 

Thanks for the help. It was my first pump timing experience. I set it to 15.5. I do pull very heavy loads with it. Most of the time it is driven empty. I have already noticed a power and fuel economy increase. If anything, my low end seems to better than before.