Anything can happen....take a look

[preacherboy24]

Here the driver had an 870 with 1.4 million EGR miles on it. He was running two gallons of Lucas every oil change to keep oil pressure when he finally decided to do the rebuild. Guess what?.....take a look. the wrist pin broke and was rubbing the side of the liner.

[gearhead]

Just dam lucky that the piston didn't get cocked and jam up. Then the block would have a big hole in it.

[RPM1]

there is a snap ring that holds wrist pin in , that to me looks like piston skirts rubbin on liner as piston tilts im sure that rod in junk also at the top / piston end

[DRISX]

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.

[gearhead]

I have a thought on why liners drop on exhaust side of the engine other than it being the thrust side of the engine. I think lugging is a major reason for liner drop.

[preacherboy24]

Take a look at this carnage! I'm impressed.
https://www.youtube.com/watch?v=S9tU_uGBDKU

[RPM1]

(03-05-2016 )gearhead Wrote:  I have a thought on why liners drop on exhaust side of the engine other than it being the thrust side of the engine. I think lugging is a major reason for liner drop.

my guess would be heat , heat is a killer will take tension out of rings warp heads valves turbo's
exhaust manifolds bolts an pistons . depending on how the coolant flows in the engine my guess on the exhaust side there is hot spots , sure the engine will cool going by the temp gauge but there is rarely even cooling in a engine a there is always hot spots , that being said metal will compress more on one side if its hotter then the other , so if u water temp is say 200 an u exhaust is 800 over time i can see how the would compress a lil more . one side the head u have cool air coming in an the other u always have hot going out . heat will make u power but it will also shorten u engine life . just my 2 cents

[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.

[Wiseman]

Hammerhead , it's not so much about air speed , but more volume of air . Diesels rarely run at stoichiometric . Most of the time they run lean and respectively low EGT . When pushed hard there's barely enough air to provide proper combustion . The molecules of oxygen content in the air itself is what is getting in reaction with the fuel molecules. To make it easy to understand I'll say : given amount of hydrocarbons can get in reaction only with corresponding amount of oxygen . The excess oxygen and the rest of the gases in the air are heat carrier to outside of the combustion chamber . So here it comes: Not enough air - high EGT . To much air - very low EGT . To get the best efficiency of the engine is a matter of a fine balance between both and correct mapping of everything else . Very difficult task!!!
Unilevers , Gearhead and Rawze have gone a great distance researching and experimenting to find the best compromise for most every day use . On other hand you're on the extreme.
I think you need CM870 CPL8518 with HX-60 touched by one of this highly regarded guys.
Disregard what I think . It's just biased opinion.
People are saying: torque is needed to get rolling. Power is needed to keep it moving ones it gets to speed . With 1600-1800 rpm engine is in the power band to do what you need . The torque curves down to protect the engine from to much stress and rpm/power takes over .
The best place to put your pyro is just before the turbo so you have the exact temperature that hits the turbine . If I recall correctly anything above 1350-1400*F for more than 5 min will kill the turbo . The probe on the outside takes time and if fan is on , the readings is just a guess of what actually hits the turbine, cage and nozzle.
It's just my take on this pyro probe placement .