I know my best bet is to call a shop and discuss current issures and performance modifications but just thought I'd throw this out there for now. I have a ton of questions about this motor! First, what is is currently capable of, power wise? What turbo is currently on the truck? Injector part numbers? How to advance the timing? How to make pump adjustments for more fuel and RPMs? Turbo upgrades? But being Cat guys, my dad and I were thinking maybe timing is off? Which most likely points to leaky injectors. The only problem is that it smokes real bad, the owner said even after it warms up and even it the summer it doesn't clear up completely.

It starts right up just fine, the day I looked at the truck it was probably 25*F out, I turned the key, hit the button and it didnt roll over once and fired up. The motor and transmission supposedly only have 50,000 miles on them. The 2nd owner of the truck bought the truck with a bad injection pump gear drive and had it replaced. I will be the 4th owner of the truck, the guy I bought the truck from personally knows the previous two owners. The gentlemen I purchased the truck knew a little history about the motor but wasn't 100% certain. So the common rail 855 is completely alien to me. My father has owned 4, 3406s and thats about all I know. For the little knowledge that I have about big cube diesels, it's all Cat. This is my first class 8 truck, I bought it for a little restoration, puller, Sunday driver project. This past weekend I picked up a 1973 Kenworth W923 with a Cummins NTC-350 855.

Cummins 350 big cam valve adjustment