[faclark47]

Does anyone know about a Cummings 903 diesel engine that is in an 82 Newell. It is available in FL. I've heard this one smokes a lot (haven't seen it yet, I'm wondering if it is worth seeing or if the bad smoking is indicative of a major problem).

[encantotom]

howdy,

it is a cummins, not a cat

i dont know much about them. hopefully someone else here does.

tom

[faclark47]

Thank you, Tom. It is indeed a Cummings. I was talking to the salesman today and he said it was a Cat and I didn't go back to read the description on the website. The question, corrected, remains so I hope someone can comment on the Cummings 903 and the extent to which it smokes when started. Normal or sign of problem?

[HoosierDaddy]

If it's a Cat it's probably a 3208. If its a 903 it is a Cummins V8 which is common in Newells of that vintage. Any diesel of that era willsmoke on start-up. There's blue smoke,white smoke,black smoke and any combination of those three. It is impossible to diagnose a problem just based on whether it smokes or not.

[faclark47]

Thank you, HoosierDaddy. I've got a lot to learn about older diesels including the significance of the different colored smoke at startup. And I'm grateful for any education I can get here.

[HoosierDaddy]

Generally:
Blue smoke = crankcase oil burning (leaking past piston rings or from valve stem seals etc) . However blue/gray smoke on start-up is normal and is caused by an incomplete burning of fuel due to low combustion temps.
Black smoke = overfueling
White smoke = underfueling (fuel injector plugged etc.) or more likely coolant entering combustion chamber due to head gasket leak etc.
Watch a few you tube videos of diesel tractor/truck pulls to see the difference in smoke. Here is an example of underfueling initially then becoming overfueled.

http://www.youtube.com/watch?NR=1&v=cpNt...ature=fvwp

It gets way more complicated when you add turbo-boost pressure/air/fuel mixture and fuel quality to the equation. I dont mean to over-complicate it ....because it is complicated. There are a few guys here at Newellgurus who have more knowledge than me so I would yield to any corrections they might feel necessary to add!!
In summary, it would be normal for that 903 to smoke a bit on start-up then clear up until the accelerator is depressed. Then you will probably see some black smoke until the engine reaches the requested rpm.

[faclark47]

To repeat myself, Thank you, HoosierDaddy. This is a helpful summary that I can memorize. I'm sure it is a whole lot more complicated but I'll learn one step at a time. I'm glad this group exists to help us newbies.

[hagcam]

The cummins 903 is a V8 as stated earlier. It is 903 cu inches. From what I have read it is a good engine but was not that popular in North America. It was more popular in Australia where it was used in semi trucks. The US military has used them and occasionally you will see on of their rebuilds on EBay. I understand that they didn't have a great reputation in the military.
A friend of mine has one in his Newell and likes it. It has a turbo and I think they are around 300-330 HP. He claims he gets 8 MPG with it.
If you ever watched the TV show from the 70's, I think it was called movin on, it was about truckers, they had a 903 in their rig.
I understand that because they were not that popular, parts are expensive (heads $1000). It is a big heavy engine I think around 2800lbs.
Keep in mind that I have no first hand experience, but as I said my friends in his Newell, burns almost no oil, doesn't leak, and he loves it.

[faclark47]

Thanks, Peter. That is helpful. Interesting bit of history there, too.

[HoosierDaddy]

I had a '78 Newell with the 555 Cummins in it. The 555 is a smaller version of the 903. It was adequate for the 35' Newell. It sounded great, did not leak or burn much oil and got 7 mpg. It would slow down on a long hill but would run 70+ mph all day long on the flat. These engines were used in short-haul day cab trucks as well as agricultural and construction equipment in the US. There were some issues with crank-shaft breakage when placed in severe duty (military applications) but they seem to hold up very well in motorhomes. One key issue on any motorhome is cooling system maintenance. One should be very thorough on keeping the radiator clean. Mine get steam cleaned annually with Lighter cleaning between trips. If you are looking to buy a motorhome check the coolong system thoroughly. The older rear engine coaches blow the cooling air out the back through the radiator. Consequently any oil leak gets blown through as well and will quickly plug the radiator as dirt builds up on the oily surface. Also diesel engines of this vintage typically had "drip tubes" for crank-case venting. It is normal for a small amount of oil to exit those tubes. The tubes on my 555 exited the top of the valve covers and terminated near the bottom of the engine.