250 Cummins Jakes

The C in NTC actually meant Custom Rated. A end user/manufacturer would spec a certain CPL for their application. Example,NTC 335,had no aftercooler.
Also early NTC 350's such as small cams,did not have top stops,they used regular PT injectors.

 

Thanks your correct. Was the 335 the one with the roots type blower or have I also twisted that up also? Maybe that was a 380?

 

The old C-180 Cummins had the mechanical supercharger,(blower) or the "iron lung",as it was nicknamed. NTC 335's had the old VT 50 turbocharger.
NTA-380,NTA-420's were the big dog in their day,Cummins first aftercooled truck engines. The A mean't aftercooled. Used to see them in mostly KW's,Petes.
Upper left pic,was my first truck,1969 IH COF4070A. Had a NTC 335 Cummins,13 spd direct UD trans.,4.11 gears. Great set-up. One of the best pulling trucks I ever owned,had a custom tune,turned way up,just had to keep one eye on the pyrometer at all times. Cabover pic is from 1974,some of my other old trucks,all Cummins NTC power.

 

If it is a small cam NTC,or Big Cam I,you should be ok. Probably a model 30 Jake. Later Jakes were for the lower oil pressure Big Cam Cummins models,Big Cam II and up,I believe. Won't work for you,because of the oil pressure difference.
Old used Jakes are around,not much demand,you should be able to pic a set up for cheap,if you look around. You will need the pump switch,clutch switch,dash switches,and wiring also.

 

Thanks for taking the time to share that with pictures!

 

Your not the only one. My old man claimed his 74 K100 with a 420 NTA and some work was the Best pulling engine he ever had pulling A-trains. But his last truck when I was done he agreed it was better. N14 625HP/2250TQ. Only took 42 years of tech for him to find another one he liked that well. Great pics. Thank you

 

Thanks,your old man and I sound similar. Here's a pic of my last truck I owned,1995 9300 Eagle.Had it 21 years,before I retired. It was a N-14 redhead,cpl1844,500 hp,15 spd. Had the ecm torque set at 1850,was plenty for me. Outstanding engine,don't really miss trucking that much,but I do miss that truck.

 

I need to buy you a beer and talk to you about that n14. how did you avoid the fretting problems with the high hp and torque?

 

Well as of 996k no fretting yet. Drive it like a steam locomotive. Slowly build the fire. You can't mash on it. You can't lug it. Still 10k oil changes. Double clutching. And allways watch your gauges. And a guy that does great program work. Now if you have the engine out of frame. Line bore the crank journals. You wont have fretting.