Hi,

this concerns a farm/yard/feeder tractor with a very high idle factor. It is a Case IH 5120 with a Cummins 4BT/VE Pump. The worst thing is the B7 we have to use. Biodiesel is hard to atomize, clings to the cylinder walls due to its polarity, and is less volatile than petroleum diesel, meaning it does not boil off your engine oil in normal service. Haze at take-offs and fuel dilution happen to be an issue with this tractor, black smoke does not!

We are due for new tips or injectors, ideally an upgrade. Power-wise, we want to stay boring at about 94 HP, what's needed is durability and long oil drain intervals.

OEMs are #3919322, Lucas. I was told they use nozzle #6801118 = 4x0.0114.

The corresponding Bosch injectors are Cummins #3919343 or Bosch #0432 131 835, tips = DLLA 155 P274 = 4x0.012, IIRC.

A local diesel shop offered to rebuilt our injectors with 5-hole nozzles, Lucas #6801131 = 5x0.0108 (??). These nozzles have actually been used in 125 and 132 hp 6BT VE-pump engines in Case IH tractors. Would you consider this an upgrade?

If not, we are probably looking at all new injectors, I have been thinking about VCO-type nozzles, but I am afraid that "low lift needle deviation" is indeed a problem with the short injection events at low rpm. From what I have read, VCOs have been developed to reduce hydrocarbon emissions found with sac-type nozzles.

At what point will the excess fuel normally leave the sac? After the injection event, through the exhaust stroke, the inlet stroke, or????

Where can one find a comprehensive list of all 7mm 155* injectors?

Thanks for your input.