RIP CM2250, 2013, 800,000km 20,000 hrs

[Waterloo]

A used head will fail in short order, do not waste the money, plenty of posts regarding these reman heads. They are garbage, an ISX head is a one time use only and throw it away. It is not the flatness, as ISX heads rarely if ever fail. It is the liners that ruin them when they cut loose. And then there are so many intricacies involved in restoring these heads, it really is not possible. You are just throwing an old worn out head with some new shiny bits on the motor, as the damage that is there is honestly not repairable.

But, more times than not, Cummins sells new heads as remans, the dirty little secret few if any dealers will tell you. You will have to check the welded code at the back of the head. If it starts with RX, it is a reman and should be avoided. Also, reman heads come in skinny crates, new heads come in big crates. So, make sure you check that number before purchasing. Open the crate and physically check that number.

I would not even attempt to put a 6NZ in that truck, all of the electrical/cab issues and so on, not worth it in my book. And I do like that motor, it is bullet proof, but is not intended to go into a modern EPA truck. Here is what I would do...

If it were me, and you are going to source a block, I would go with the CM-871, and build it myself. That means cutting the ledges to .014 in regards to liner height, and go from there. New head, the correct OEM in frame kit, new injectors, etc. This is a less complicated motor, and when rebuilt properly will go one million miles plus. No fuel pumps to worry about or other issues with the fuel system. It should drop right in and I would think would wire up fairly easy to the cab, may have to swap some pins around, etc. Others have done it, so it is doable. And if you want to delete, it is very easy to do, I did mine in the driveway back in 2014. I can send you the newest version.

As far as the ECM, I do not believe it would be that difficult to get the correct factory program in it, but that is a question best answered by Rawze or one of the guys here that have done such swaps. I would rather put up with the headache of going with a CM-871 swap vs having to live with another ticking time bomb that you are replacing. You have already been through it once, twice would really suck.