Cummins V903

[Axialflow1688]

Originally Posted by madsnake

Had a 4840 MF with a 903 bought it at 7500hrs traded it at 10000hrs, uncle bought it then and used it for 3 or 4 years before stoping farming so up around 12000hrs. Never let use down did get a tune up and injectors while we had it.

Madsnake

We have a 4840 also and it is a complete work horse. we bought it about 5 years ago from my dad's cousin and they had it for several year and never had a single problem with it. I talked to guy we do a lot a farm equipment business with and he is about 80 years old and he told me that the 903 cummins engine is one of the best engines, but it is also one of the high maintenance engine too. If you take good care of that 903, it will last you forever.

[10prostocker]

Well 903 was not a real power house in on road trucks due to fly wheels and cranks twisting is what a retired cummins rep told me but they are like gold to buy now these days if you find a good VT903. And If you guys want to see true power out of 903 block check out Chizek/Blackbourns International Threat MX255 Skin it burns alky with 4 turbos and custom aluminum overhead cam. And the other 903 block in a 1466 skin run by Campbell know as controlled chaos. I know where there was a 4070 COE IH truck for sale with a 400 hp 903 cummins

[CRToney]

A few points to consider. Rebuild costs higher with 903, 5 main bearings instead of 7 with 855, higher fuel consumption, poorer torque characteristics with short stroke V8, higher rpm hp so more noise, easier to work on inline six. Need more power out of 855 add dual line to front of head, FASS fuel pump, get pump governor set to rpm you run at.

[jd95guy]

Originally Posted by CRToney

A few points to consider. Rebuild costs higher with 903, 5 main bearings instead of 7 with 855, higher fuel consumption, poorer torque characteristics with short stroke V8, higher rpm hp so more noise, easier to work on inline six. Need more power out of 855 add dual line to front of head, FASS fuel pump, get pump governor set to rpm you run at.

Disagree on the torque. I could take off with the plow in the ground at an idle with the 950. Couldn't do that with the 976.

[CRToney]

Look at the hp curves for each engine ( hp is rpm x torque x constant) max hp is at a higher rpm than the 855. A poorly set up governor along with other factors could explain the poor off idle response. Compare a powerstroke to a 5.9 cummins put each in 3 rd gear and dump the clutch the powerstroke will die and the 6 cyl will chug away. The 903 belongs in a boat or tank not a tractor.

[jd95guy]

Originally Posted by CRToney

Look at the hp curves for each engine ( hp is rpm x torque x constant) max hp is at a higher rpm than the 855. A poorly set up governor along with other factors could explain the poor off idle response. Compare a powerstroke to a 5.9 cummins put each in 3 rd gear and dump the clutch the powerstroke will die and the 6 cyl will chug away. The 903 belongs in a boat or tank not a tractor.

It didn't matter if it was at an idle or full rpm. It would still OUTPULL the 976. I could go up and down our hills no problem with the 950 and the 976 would struggle. We made a pretty good living with the 903 and there are still a lot of them in use around here.

[onionfarmer]

The 903 is a great engine I have almost 19000 on one 14000 on another never been apart. It will start any load at idle I wonder what could be done with the electronic fuel systems of today. The guys that talk trash about a 903 do not know what they are talking about.

[ozcase8120]

Know of a steiger panter 350 with a 903 in it, tractor done over 50000h has had 3 or 4 rebuilds but its was a beast, sits in the shed now since they brought a 440 quad back in 01

[8850jd]

at least they were smarter then deere and let the v8 just be an engine and not just a frame, the 855 is a good engine but it is not a v8.. The v8 is more like the john deere 466, coffee can pistons, with a shorter throw then the cumins 505, which had a longer stroke, but smaller holes, (i could be wrong) so they will cycle faster.
The other reason the v8 would have better responce is simple, you have two more explosions per rotation, not hard to grasp,
The only way you can accurately test these engines is on a dyno, your 976 could have been short on power, and the v8 could have been running a little hotter,
the 855 needs To run between 1600-1850 for ideal power in my opinion, anything lower and u are not helping the cause, higher and your spinning your wheels, depending on load.

[CRToney]

Read "A Diesel Odyssey" Lyle Cummins book about his father Clessie. When the 903 and 555 were developed he was against it. Cummins had a fair bit of trouble with those engines. If Clessie was still at the helm we wouldn't have those engines today.

Why do so many guys repower the V8 tractors with an I6 like KJ repair at Ponoka?