I am working with a 1978 NT855 engine on a stationary fire pump.
The fuel pump is a PT type. When the engine starts it will idle until the oil pressure builds and the plunger slams the throttle lever to the set point of 1600 RPM, at that point the engine throttles up fairly quick causing water...
Davidbeach, what is the reason and concern for using the 208delta 480wye transformer not the common 480 delta 208wye? I have a feeling that I’m not the only one that has made this mistake.
Injector torching due to a cracked tip sounds like a good call on this piston. There was a case on one of these where some of the piston material was imprinted with head as it came up on the return stroke. No serious damage..
Thanks every on for your insightful input. After 100 hours of run...
No in each case the cavitations were noticeable but not deep enough to penetrate the liner.
In regards to the injectors, the last break down they were sent out by the firm that was called in to do the work on engine and it was reported back to us that the injectors were fine. This time I told...
Thanks rmw.
The green goo has not been a problem in this case. We do use a coolant filter with the DCS additive and it seems to work quite well keeping deposits from building up. That is a good point to watch for on further inspections.
I found some photos of the inside of the block and...
I have herd that the coolant gets viscous when cold but never experienced it.
In the past I have gotten the old green coolant from our motor pool. It was a premixed 50/50 (tested to confirm). Now on this motor I’ve been told that the “ yellowish universal coolant” is all that is available, so...
rmw thanks for the suggestion, It is interesting how the cooling system has been modified to adapt it to a stationary application. On this set up the radiator has been replaced with a water cooled heat exchanger. The engine has glycol in it as usual but it circulates through the heat exchanger...
Yes I agree there is much more than just popping the cover to have a “look see”. I thought I’d spare the details of using the dial indicator on the top side to get the timing settings and adjusting the rockers for intake & exhaust & injector clearances.
Thanks for the reminder.
Thanks for the input everyone. This forum is invaluable for taking a problem and looking at it from many points of view and coming up with good solutions.
Dicer, early on it comes back to me that the first person to work on the engine did go through and adjust the timing with the shims under...
Ivymike this a good point. The injectors have not been changed out. We were told that they were bench tested and showed to be OK.
For what injectors cost we are having new installed this time around.
Potteryshard Another good point. The cam lobs have not been checked at this time. I’ll...
The NT855-F1 was built from the standard block casting but it was re configured somewhat different to meet the NFPA standards for the time.
The oil gallery on the right side where the oil nozzles are, was made with no feed lines open, there is no oil spray from nozzles cooling the pistons...
I’ve been working on a stationary pump engine that has been giving us problems for 5 years. It is a 1978 Cummins NT855 F1 for fire pumps. The engines it has ~ 2K hours on it, most of that time is from exercising 30 min per week pumping at the given rate of the system.
The problem we are...