Author Topic: Details on Cummins VT-903  (Read 2365 times)

Rotrucker

  • Full Member
  • ***
  • Posts: 26
Details on Cummins VT-903
« on: July 06, 2008, 09:00:48 AM »
Hy guys

I got again some technical questions. Do the Cummins VT-903 have the same injection type like the Cummins NTC, or is it something different? If yes, where is the injectionpump? Perhaps some of has some detail photos on that engine, it will help me alot to see how it is build up. I serched the internet but it was impossible to get good backround informatio.

Thanks alot.
So long
Arnd

theakerstwo

  • Sr. Member
  • ****
  • Posts: 54
Re: Details on Cummins VT-903
« Reply #1 on: July 06, 2008, 09:52:20 AM »
Hy guys

I got again some technical questions. Do the Cummins VT-903 have the same injection type like the Cummins NTC, or is it something different? If yes, where is the injectionpump? Perhaps some of has some detail photos on that engine, it will help me alot to see how it is build up. I serched the internet but it was impossible to get good backround informatio.         The 903 engine has the same fuel system as a inline NTV and the pump is located in the top of the V.    glenn

Thanks alot.
So long
Arnd


wig wag

  • Hero Member
  • *****
  • Posts: 663
Re: Details on Cummins VT-903
« Reply #2 on: July 11, 2008, 04:34:48 AM »
As Glen says, it uses the (P T ) pump as all cummins engines of that era, Approximately 1957 till they developed the electronic
injectors in the late 80's early 90's. The pump is driven off the compresser which in turn is driven from the grear train housing
at the back of the engine. The pump is located down in the "V" of the engine between the intake ports. Interesting thing to note
is, there is a turning gear, used to bar the engine over when setting the valves and injectors, located in the compressor mounting
flange. It is held out of mesh by a hitch pin clip. You remove the clip and push it in to engage the gear train, and you can rotate
the engine with a bar and socket instead of using the bolts on the vibration damper, or a large screwdriver in the flywheel ring
gear.
The early engines had an internal ventilation problem that caused the oil to collect up in the right bank rocker cover. The engines failed due to low oil in the sump.
To remedy this they removed the breather from the rocker cover and intalled a plug that was drilled and tapped and inserted
a 90 degree hose fitting and ran the hose over to the same hole that the turning gear formaly uccupied. This gear was removed and the hole tapped to attach the hose from the rocker cover. Sort of like a PVC setup. They modified subsiquent engines so that
they where internaly vented.  So if you run across an engine that has a hose fitting by the compressor mount and no turning
gear, make sure you vent it properly.
It was a perplexing situation, having an engine fail due to lubrication starvation, but when the engine seized the oil ran back down
from the rocker cover and the sump level was then normal! WTF!!!! :?
If you come across an engine that has no oil pressure, be very careful when dropping the oil pan as it may be very heavy due to the
oil pump assembly having broken off the bottom of the engine. These pumps are big. and you don,t want your face to be hit by the pan. :x  Remember the first law of physics. Two solid objects cannot occupy the same space at the same time while your dental
work is in between them :-o