I own a F250 85 4wd 6.9 diesel truck. I just did rebuild the truck, including a complete engine overhaul.
The work on the engine was done very carefull. New pistons, rings, bearings were put on the engine.
After the work on the engine, it starts without any problem, runs nice, no oil leaks, excellent oil pressure, water temperature perfect.
What I am not happy is with the truck perfomance on hills. It lacks power very easy and I have to shift from third to second and sometimes use first speed. Compared with other trucks on the same hill I climb it using an Isuzu 2.8 l small truck using third speed without any problem.
From Ford history, it is suppossed that the F250s 420 cubic inch Navistar diesel offered just 170 horsepower but it made 315 lb-ft of torque, making it more powerful than any Ford truck engine with the exception of the 460 V8.
In my case my truck lacks the torque it should have.

Any comment on that or idea to increase perfomance on the truck? I am not looking for speed just I need power. Is the problem on the gear relations?

Please comments on this.

Marco Venegas.

 

get a turbo of turn up the fuel

 

Old 6.9's are nothing compared to more modern diesels or Gassers in terms of power. They will haul anything you put behind them, but they are pretty slow going up hills, I know I have a stock 6.9 in my Motorhome. Best thing to do if you really want more power is putting on a turbo.

 

did you overhaul the fuel system and set the timing correctly?

 

NO I haven´t done anything to the fuel system!

 

If the fuel system is original, I am going to say you are probably overdue for an IP and injectors.

And then injection timing would be the next thing I would look at.

When you first start the engine does it sound like it has a bit more rattle than it does after the timing advance and high idle kick off?
If the answer is no, then I would guess the timing is a bit retarded.

170 HP in a 7000 pound truck is not going to be that peppy, but it does sound like you are lacking some.