Big Cam 3 Jake brake install

[JDirt]

Yes, we checked for bent pushrods, ran the overhead as Truck Shop described, and made sure the pushrods were in their sockets. I sent the #2 injector back to Cummins, I should have another one tomorrow.

 

[Former Wrench]

It has been years since I tuned a NTC series engine, but when doing the injectors, I always "exercised" the adjusting bolt. I would tighten it to 10-12 in/lbs and back off before doing the final setting. I would do it a couple times before the final set. My logic was that I was pushing any oil or other out of the threads to get the most accurate setting. Could have been nuts for doing it that way, but it made sense at the time.

 

[Truck Shop]

Could have been nuts for doing it that way, but it made sense at the time.

I did/do the same.

 

[JDirt]

I ran the injector screws down before final adjustment as well.

So we exchanged the injector, the one in question must have had a broken spring or something, the plunger sat down about 3/8" lower than the new one. Truck starts easily and no miss.

Today we hooked the trailer on, loaded the 953 and went for a drive. Seems about like 300 hp to me. Almost no smoke at all. Surely a fresh engine, new injectors, fresh fuel pump (supposedly built to cpl 625 + 15%) should be more powerful than the worn out turd it had before. Am I missing something?

 

[Truck Shop]

Did you change cam/injector timing? Was it a 625 cpl to begin with? Does the turbo match the 625 cpl?
Did you replace the fuel lines from tanks to pump plus return line?

 

[JDirt]

Did not change timing or turbo, the tag says cpl 625, everything that came out of and went back in were the correct parts for a 625. When I sent the pump off, I gave them the engine info and told them I would like it to have a little more power, when it came back, I was told it was built to specs for that cpl (400 hp @2100 +15%) Surely at 460 hp it would make considerable smoke?

 

[Truck Shop]

What type of fuel hoses are in it now? original? Is the return hose/fuel line braded hose?
If it is remove the hose at engine and see if it is swollen inside. Check flow on return hose at
tank.

 

[mekanik]

The air fuel ratio control may be set too low. The adjustment is under the plate
at the throttle shaft. You need boost to get fuel pressure and you need fuel pressure
to get boost.

 

[JDirt]

I talked to the shop that worked on the pump, he says stock settings for cpl 625 + 15%, with a #25 button. Also said I could change buttons if wanting more power, but should install a pyrometer with a #15. I was also wondering about turning the screw for more pre boost fuel.

 

[mekanik]

Bend the plate and loosen the lock nut and turn the screw out 1/2 a turn to start.
Go a 1/4 turn at a time if you need more.

 

[Truck Shop]

A good pump shop/experienced will automatically set air fuel ratio 10% over the turbo lag.
But most if told to set pump up 10% will only change fuel button. Yes it produces more smoke
because of turbo lag but better throttle response.

 

[oarwhat]

Bend the plate and loosen the lock nut and turn the screw out 1/2 a turn to start.
Go a 1/4 turn at a time if you need more.

We had an old Oshkosh snowplow with a rebuilt 350 Cummins. Just gutless. Adjusted the air fuel and wow what a difference. Don't go too far. It'll run like a raped ape and smoke like a chimney.