Insight on a Cummins N14
 

Not being familiar with the bigger Cummins' anymore, are the N14's any good? Inherent problems? Things to watch out for? General reputation? Looking at a truck with 750k on the odometer and wondering how close to the end of its' life this N14 might be if it's been well taken care of.

The N-14 is bullet proof. They are 1 million plus mile motors.

Thanks Guardrail, that's what I was looking for.

What about the 'M' series motors? Same thing?

I'm looking to get a new truck and I seem to keep looking at trucks with either the M's or N's.

L-10

M-11

N-14

K-19

L10/M11 are different than the N14 and the K19 is different than all of them. but the 11 was a replacment for the 10. The number is the displacement of the engine is Liters. can't really compare a 10-12L engine to a 14-16L engine though. the M/ISM are pretty reliable, theres TONS of urban busses running the M series and I've seen lately quite a lot of firetrucks/pumpers with a 500hp ISM. and allison.

Arguably, ( because we all have our own opinions ) The N14 was quite likely the best engine cummins ever put together for a highway application. Lots of power, pulled great down low, didn't hog down fuel, and if you didn't overspeed it, would run with minimal problems for a LONG time.

The newer engines are nice, but they don't go nearly as long before they start having problems.

I completely agree.

We have 4 of them, an occasional injector or crank sensor, thats it.

Scott, check the idle oil pressure with the engine at full operating temp. It should be right around 20psi then 40 above 1000 rpm. If it is lower the 15 psi at idle then it most likely needs cam bearings, (big job). A standard bearing roll "will not" improve oil pressure. However, if the low oil pressure buzzer does not sound when taking off loaded then I would not be overly concerned.

Thank you everyone! This is exactly what I was looking for. I need to know everything I can because I'm not familiar with these bigger engines and more than likely whatever I look at will be quite a ways from home.

Tim, those oil pressure readings are what I'm getting with my 466 now, so they'll be easy to remember!

T-Rad has agreed to go look at a truck for me that's down his way, (sorta!). I'll make sure he sees this.

Tim
The only other grief I have experienced with the N14, besides timing sensors and push tubes from overspeed, is the wiring behind the engine, leading to the battery box.

Yeah, that special wire that provides all the power to everything electronic... and is the only place that green doesn't mean GO.

But yeah, bulletproof.

We rebuilt the N-14 I'm driving pulling 105,500 lbs at 875K miles only because I had a water leak in #6 cylinder. It's always been dependable & I have 985K on it now. I'll turn a million miles at my next oil change. The last truck I had was a 400 big cam 3 cummins & we traded it off for a new one at 1,400,000 miles with one in frame at around 900K

How well does the rest of the truck stand up with that many miles on it? Sloppy rears? Loose tranny's? All kinds of rattles in the cab, etc. I realize a lot depends on how well it was cared for in the first place, but in general how do things fair?

I've driven a freightliner cabover with 2.4 million kilometers on it that was in 100x better shape than most of the 1.0M km< fleet conventionals that I have to work on.

IMO it is impossible to speculate.

I don't know much about the N14 other then that I have heard they are bullet proof, but wit that said I work for truck reconditioner as my job well I'm in college, and you can have an 07 come in that is just trashed cause no one took care of it, and you can have 2000's come in that are tight as the day they drove off the lot cause they were well cared for.

i love this engine, like stated before main thing with them that seems to go the most is injectors, and engine position sensors, the cam boxes like to leak every now and then, and some may already know this, but the gasket thickness on the cam boxes actually determines the timing of the engine, it's weird, and kinda a pain to have to adjust. as long as the truck you are looking at has been somewhat cared for, and maintenence has been kept up, that engine should keep on runnin, i love the way the sound idling, maybe even more so than my B engine....

Wes

Well the truck I was looking at was sold Friday afternoon. [verymad] But as I continue in my search, I'm going to try to find something with the 'N' engine in it. Seems like it's what I'm looking for in terms of reliability, longevity and power.

Thanks everyone!

I will use your vernacular from a response you made in a post I did about a ground cable. "Ground effect widow maker", just on the power side. [laugh][laugh] I love the way the ecm power line is routed. [duhhh]


Hope things are well for you up in the Great White North.

I've never seen a Cummins, let alone a N-14 hit close to 40 psi. Humm...

I have NTC motors making 100psi on cold start, then running 60+psi all day long. Any N14 I have ever dealt with that was in good mechanical order has always made 40 psi over 1000-1200 rpm. We have a 2001 Pete 359 with an N14 460hp, it has made 50 psi on cold start since it left the dealer lot new and runs 40-45 all day long, 400k on it now with well over 22k hours on it. Chevron Delo 400 and Hastings filters are the only oil and filters ever used on it.

I guess you havn't driven many cummins. In 35 yrs thats all we have bought & my N-14 runs 40 psi all day long while under load. Granted the big cam 3 I had before this one ran at 38 psi I had 350 before that one & a 290 before that & they all ran close to 40psi.

N14 in later years (2001-2002) is statistically one of the most reliable HD truck engines ever made. The warranty data proves it.

Also the later ISMs were exceedingly reliable.

If you have any questions on 2010 or current generation Cummins HD engines (15L 11.9L) then I can probably help you a bit on that. I eat, sleep, and breathe those things (fuel system) all day, every day.

Thanks Justin. As I'm wading thru all the truck ads, I'm hoping that whatever I find will have that N14 in it. What's the scoop on the late 90's and early 2000's M series motors? Are they somewhat small? I see some of them putting out in the 400HP range, but if they're a small motor I'd think the reliability and longevity would suffer.

Ms have always been in the 11L range, going back to the M11, then later the ISM.

The ISM has a sterling reliability record in recent years. The latest version is still new, but the models up to 07 were very good units. The 425hp rating should work well for you.

the 4000 series Allisons in the new fire trucks with 500hp ISM's looks to be a killer combo.

As an update to the whole thread, I'm going to look at a truck on Monday that has an ISX in it. Naturally, it's the only motor that hasn't been discussed here.

Yeah, your right. I've only owned 3 N-14s and driven several hundred N-14s and ISXs the rest of my 18 year driving career. I guess all the gauges are off on these new trucks that I don't drive. Operating oil PSI is lucky to hit 38 and most times runs about 35.

ISXs have had an issue with EGR coolers. (our new ones are still having issues) If the truck eats coolant, check it.

The 'it'? Can you elaborate?

it = the egr cooler.

35psi is about right. That's what the regulator is typically set to.

More oil pressure isn't a good thing if you don't need it. Think about it-- if you can lube the engine successfully at 20psi, what's the advantage of 40psi?

Where does the work to make that oil pressure come from? How about from the fuel your are burning?

Lower psi= better mpg.

Cummins has devoted a TON of effort into the EGR coolers. Lots of testing and experimenting, and even a change of suppliers to improve the quality.

If the truck eats coolant, the EGR cooler is the first place to look.

But the 2010 products have *vastly* improved EGR coolers over the 07 products (I'm pretty sure the 07 coolers have been improved also for svc).

The EGR coolers were eating Cummins' lunch on warranty cost. Lots of incentive to fix it, and some *really* smart people working on it (not me-- legitimately smart people).

JH

2010 is pushing less egr than previous years, and by a lot. with the bluetec gear. less regens. better economy because of fewer regens. and less EGR issues with moving much lower volumes of egr.

Yay epa 2010

Thanks! I thought that's what you were referring to but wasn't certain.

I bet I could delete it.....

:D

Our 2010 engines are having EGR cooler failure quicker than the older models. (less mileage)

Not sure where the "the" came from, it's gone now.

what engine?

Actually the reason Cummins lowered engine operating oil pressure was not due to fuel economy but rather excessive oil temps from higher oil pressures, any other benefit was secondary at the time.

ISX 455 horse.

strange, the DD15 is way better in EGR reliability than the EPA07 series 60s.

Cummins ISX