Turning up power on PT pump on 855

[CToney]

We have an 835 Versatile tractor with a 855 cummins in it. Its a 1982 model rated at 230hp and 800 lb ft of torque. I would like to know how to get up to 250hp and 850 lb ft torque out of it. I think all one has to do is remove a plate from somewhere on the injection pump and drill a larger hole in it but I'm not sure of where to do this at.



I hope someone can help



CR Toney

 

[Lnwing]

Diesel Injection of Pittsburg has been tweaking the 855's for years. Go here for lots of info:

http://www.dieselinjection.net/frames.html



Click on "Bruce's Horspower and Torque Articles".

 

[MontyDyer]

If it is turbocharged and has the aneroid head on the back of the PT pump, all you have to do is put a bigger button and spring in the pump from a 250, 290, 335, 350, 400 etc. However, there are better and safer ways of turning the PT up ,however, it takes some calibration from the stand. A good tech on a calibration stand can make a PT pump engine really run awesome and still stay within the factory tolerances. The spring and button is a cheap easy way but can get a little toasty if you dont watch your foot.

 

[bmoeller]

Get a pyrometer, whatever you do. Don't get any bogger implements, just pull it faster. Clutch may not be happy about it.



Don't recommend it, but you could just put a pair of Vice-Grips on the return fuel line. lol It will increase the fuel pressure. The PT stands for pressure/time. More pressure means more fuel and thus more power. Get a fuel pressure gauge.

 

[NIsaacs]

Make sure it has a turbo. In the automotive market, most 250 hp and less 855's were N/A. Not sure about tractors





"NICK"

 

[CToney]

230hp 855

The engine is rated at 230hp at 2100rpm and 800ft lbs at 1400 rpm the other models are 250/850 280/950 the only difference I could find was rad size on the 280 hp and one extra fan blade on the 250 hp. The injector cups had a different part # for higher flow. I thought if I could do a slight adjustment I could up the power at a slightly lower rpm. We have an C series in a tractor that is rated the same but mated to a powershift doesn't pull near as well 2mph slower with same load.



CR Toney