2018 Pete 389 with Cummins X15

They are having the same liner issues that the 2250 and 2350 suffered from. They are running the compression to high in these things, and then with the higher torque levels drivers ask for, it just spells disaster. And the QC from the plant is crap. That is from Mr Hagg at Haggai Automotive and Diesel. He is the #4 Cummins engine re-builder in the country and #1 in the state of GA. Been hanging out at his shop with Rawze. Trust me, Mr Hagg sees it all if you are talking Cummins. He was also a great help in assisting me with parts during my in frame at Rawze's house.

As far as the new X with the liners, I have heard of one case. All in all though, it is having a better start out the gate than the 2250 and 2350 motors. Cummins did kind of fix the exploding fuel pumps. They still fail prematurely and blow apart internally, but the fragments stay isolated from the motor. Right now, it is their best design since the CM-871.

If I had one, an X, 2350 or 2250, I would set the HP at or below 450 and set the torque at 1650 and drive it accordingly. These motors are not stout like an old N-14 or Cat, they are very fragile compared to what we used to have available to us. You cannot beat on these things. They have to be driven with kid gloves to get any sort of longevity out of them. And DO NOT lug these motors down in lower rpm's, that is one of the main reasons for the liners busting lose in the block. Very expensive to fix.

I've got the factory 600HP CM-871 with the same set up you have, and the gearing sucks. The drop off between shifts puts you into that lugging mode, at least on my truck. I just finished my in frame here in GA, I'm installing the hood today and taking her for a test drive. My next project is to change out the gear boxes and go with 3:70's or maybe even a 3:90 ratio. I drive local and regional, I know for a fact I can get 8+ mpg all day with either of those ratios. I've done it before with much older non emission motors.

The reason for my in frame, was that two years ago a licensed and certified Cummins shop totally botched my first in frame. I made it two years to the day and 140,000 miles. #5 liner dropped. They did not machine the block as they were supposed to do and set the proper liner heights. They just through the liners in, and the inevitable happened, dropped liner and blown head.

I don't know if you know of Rawze, Rawze.com. but he called me and told me to bring the truck to his house here in GA and that he would help me in frame the motor., and we would do it right this time. Long story, took almost a month to get parts. Dealer installed 2250 parts in my 871, they sent me $14,000 in new parts, in frame kit, 6 new injectors and two new cams. I bought the new head and everything else. Rawze cut the block, and helped with installing the liners, pistons and head. He has all of the needed tools at his house. I did the rest. She is running like a Swiss watch, knock on wood.

With that set up I was getting 6 mpg, with the wrong parts in the motor. Prior to the first in frame I was getting upwards of 9+ mpg, on paper pulling a flatbed. A dry van was 8 mpg. That was with the MM2 tune that Rawze wrote. He has since updated that programming and his truck, same motor but with 3:55 gearing is averaging 8.5 to nearly 9 mpg pulling 80,000 coast to coast in a reefer. He has his HP set to 450 and 1650 on the torque. I will be setting my HP and torque at those same levels. As that is where I get my best fuel economy. There are also adjustments that he does with the timing and fueling tables, nothing stupid, just some very mild tweaks over the factory programming.

One thing we do have in our trucks, are gauges, very critical and important gauges. They will help you obtain the fuel economy and you will know what your motor is doing. If you do not have a turbo boost and a pyrometer (EGT Gauge) you really need to buy and install those. I just took my old VDO gauges out and installed a set of the GlowShift gauges, their 60 psi turbo and 1500 EGT gauges. If you don't have a set, you really need them, it is money in your pocket. Keep the boost low, under 15 psi, along with the EGT temps for the best fuel economy. head over to Rawze.com, he has many videos and quite the forum if you are interested in this stuff. I swear by Rawze's knowledge on these Cummins motors, I have seen the results first hand. And having lived with the man for two months now, have really gotten to know him personally, he is the real deal. Hell, Cummins even contacts him when they have issues. I have seen the emails.

Prior to my first in frame, I halved my fuel bill when I rid myself of the mandate and installed the MM2 tune along with the gauges. I went from $1500 a week to $750 a week in fuel costs. Of course the mandate was the big issue in regards to my poor fuel economy. It was also masking a blown head gasket from a prior high heat event that the previous owner had, hence the first in frame. I drove the truck for a year with the bad head, and 8 mpg was easily obtained, just drive smart. Hope this answered your question?

Sorry for the long post, but there is quite a lot to the story and how I arrived here.

 

Watch this:

 

I know that driveway! LOL!

 

They should have segregated the fuel pump a long time ago.

 

Wow. Not to be d$#k but why would anybody buy a Cummins?

 

Quite a few reasons really. The ECM programming is open source, and with Cummins Quickserve they are rather easy to maintain. You simply have to educate yourself. There is also a large knowledge base out there that can assist with most all problems one would have with one of these motors.

The biggest problem is not keeping up with the emissions with regular EGR Tuneups along with proper operation of the motor. An oil bypass filter is also recommended along with more frequent oil changes. Extended service intervals can lead to serious internal damage. Honestly it is the same with all of these emission motors. These are not the diesels of old, simple maintenance will no longer get you to a million miles.

 

Cause why would you buy an overpriced glider when all those engines are practically a fancy overhaul installed in a new chassis imo I would've looked into one for 25k to 30k less money on them they're ridiculous trying to sell them higher

 

Mine isn't a "fancy" over haul, it is a factory rebuilt witch was installed at the factory before it was shipped.
That said, my last truck was a Volvo 780 a 2013 i sold with 730k on it and I NEVER had an emission issue or even an engine issue or worried about exploding fuel pumps that grenade the whole motor or cost 10k every 2 years as preventable maintenance. Sounds crazy to me.

 

You got lucky