Anything can happen....take a look

[Hammerhead]

(03-05-2016 )DRISX Wrote:  That's a very common issue on all cummins isx engines , main cause is low RPM operation under high load in wrong gear . I have seeing 2 million mile ISX engines without a rebuild and still running strong , new ISX cm2250 and newer use small inducer and large exhaust side , making the low RPM operation a lot easier on the engine , in translation it does not choke up the engine because the turbo spools it up much faster . I have seeing guys snap rods , and in some occasions bend a crankshaft.

To avoid this keep the RPM's above 1350 under heavy load and under 1650 , much of it depends on truck set up , sometimes diffs play major role, not every truck was built to same spec.

I run 150-190,000lbs loaded so I've never been very big on lugging a motor, when I'm pulling a long hill I find the gear she'll pull it in, cut I back half a hole and let the motor breath. I'll do the same thing in windy days that I can't outmuscle the drag to run typical road speed. I'm usually running it between 16-1800rpm when I do this. The idea is to create air speed, get that hot exhaust moving and away down the exhaust system quicker to help dissipate heat retention.
What are your thoughts on this practice? It seems quite common thinking among the highly mechanically inclined HH'ers I know...

***edit to add for support of my theory***
I had to do an inframe at 460,000 due to a cracked head. I firmly believe this head was cracked for a very long time and I couldn't convince my local Cummins dealer of this while it was under warranty. At 460 (I time out before I mile out) the compressor failed and pressurized the cooling system revealing the crack which was in the intake side of number 2 of a CM871. Other thaa the obvious long term coolant leak damage, everything else looked good. My S/N was smack dab in the middle of the bad ones that were dropping liners like the local whore when an aircraft carrier docks, and I didn't have one shift. There was no fretting on the liner shelf at all, I didn't even have to cut the counter-bores, just dropped in the updated liners with the shims. If you want an idea of how hard I work it, I can't keep bolts on the EGR cooler over #3 & 5, the torque twist breaks the heads off them every time I replace them.