X-15 Cummins thread

IMO...
Been driving for 40 years. Have driven everything and owned trucks from most truck and engine manufatures. In the pre emission days engines offerings had completely different personalities. After electronics they started to resemble each other. After 2004 all the same except for paint colors. They all drained wallets!
Pre 2004 are confined to history. No point comparing them to present day. They're never coming back!
Present emission engines are alike, yes they have different quirks and issues. But they all have costly maintenance and don't have the longevity. It sucks!
However this what we have. These engines need TLC daily and a very watchful eye and need regular EGR + doser cleaning. First sign of coolant loss or discoloration needs investigation immediately. EGR cooler or head gasket failure investigation is required. Same for oil changes, more is better. Been there done that on ISX 500 / 1850. My liners were low at 8 to 9 thou protrusion, was within spec but would blow another fire ring eventually. Bit the bullet and had counter bores done. BIG $, but less than blown up engine away from home and time of repairs.
Drive exclusively in BC, T680 pulling 53' tridem van, 18 speed autobox, 3.70, low pro 22.5's. 46500kg or 102500 lbs. Keep my speed below 100km.
Weights are fairly consistent at 100000 lbs. Consistently get 37 liters per 100km or 6.4 us mpg I think?
These emission motors pull very well at low RPM, just because they can do it and manufactures push it for fuel mileage does not mean its contributing to long-term longevity. But it can add to significant fuel saving if used. Be careful pulling hard. If the grade is short and can be pulled at low revs, back out of throttle as rpm drops. If its a hard pull, down shift to keep rpms 1450-1500, keep boost below 20 - 25 lbs and pyro below 75% of max temperature.
At the end of couple years your wallet will repay you.
PS Eaton has non advertised program where each of the 13 or 18 shifts can be individually set, for a reasonable charge. Had mine done very happy customer.

 

While the engine I rebuilt is not an X-15, but I can say what I’ve seen so far when I overhauled the 2005 450/1,650 ISX15.

This engine is the best looking engine I’ve seen over the years when I pulled the sleeves.

There was no pitting. Clean metal. Looked like new with 27,000 hours on it. 482,000 miles/771,000 kms.

The area the sleeves sat on looked pristine. No pitting or fretting. Also, no stupid brass shims or “sealing rings”.

The aftermarket kit we got last summer has brass shims on.

The truck used an 18 speed Eaton auto shift that was programmed to shift up or down between 1,500 and 2,000 rpms.

I think this plus good maintenance of coolant contributed to long engine life and protected the block from low rpm torque.

I’m not sure of the engine oil maintenance though as we bought the truck last year.

The engine bottom end bearings, camshaft bearings, camshafts and rockers were all worn out and down to a lot of visible copper. The piston rings were broken on all 6 pistons which caused excessive blow by which was the reason the engine was torn down.

I would agree with the keeping the engine out of the low rpm area when pulling hard.

This truck runs 1,600 rpms at 100 kph.

 

I’m sure the engine manufacturer would’ve made a press fit liner type of engine for low end torque and fuel economy.

 

I always kept Casper between 1300 and 1500, and cruising was 1400.

 

Was never a Mack fan, but did own 1998 Mack Vision with big shack, E6-427 & Mack 18 speed. Was wanting T600 with 3406E or N14 at the time but non were available in time frame needed. So only other aero style was the Vision.
Only downfall was the engine brake.
In BC, effective Jake is a necessity.
With that caveat out of the way it was good truck. Amazed on how 672 cubic inches stayed together and pulled for 700,000 kms!
No inframe or major repairs. BC's rough roads and extreme grades take thier toll on components same as every other make.
Took a beating on trade-in for T680...

 

Well, I must say that was an interesting read because I've just bought my first brand new truck going from a 2001 9900 isx to a 2022 Kenworth isx performance series and have pretty much been driving it the same way, but after reading your post I think I'll change my habits a bit. Thanks, Roddy.

 

330k on my X15 and had the Inlet NOX go bad this week, picked one up from Peterbilt for $700 . Had the outlet under the bunk that I bought last year as I was hoarding parts. It was $530. Talk about inflation!!! Swapped both out as it was recommended that when one goes the other is generally right behind it...

Atleast I'll get the $200 core deposit back from the outlet purchased last year when I make it back to the dealership it was purchased from.

Inlet part # 4326870RX pictured below is outlet part #. This is for a 2020 389 565/2050 x15 performance series.