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Flatwrench

It was on 10k oil changes with 15w40 puramax north american for it's life before it broke the ring.

No oil consumption problem on this engine ever.

Note: All 5 engines were sooted on the top end. During overhead adjustments.

We have since switched to a 75syn/25con 15w40 maxtron DEO. Up to 12k miles. Now engine are clean as a cat c15 with 12k oil changes....super clean. hindsight.

We also up our game on fuel additive. Using schaeffers ND2000:1. We live in the soot, we don't demandate. We also have propane fleet bobtail that stop, go, and pto pump. I've learned this keeps us from have stationary regens. It's difference for us removing head on 20k hr isl and one looking like moon crater of carbon and one brand new. I wish we knew this sooner. Colorado elevation is challenge

We can see the difference. As a mechanic i'm not out there every other week having to run stationary regen, nor bake and blows. Pure hindsight after using this stuff. It would have saved me so much heart ache.

ISXs x15s
450hp are about 5.8mpg winter blend(we bought used with 100k miles and 10khrs...now have 600k and 23k hrs.)
500hp are 5.5mpg
565 are 5.1 and 5.9 respectively(one guy drives it like a company truck and other drives it like it's his baby)

1)Ring: they were wearing i would say worn. 2nd ring was only 50% sealing on face to liner. I don't have a great explanation.

2)Rebuild:

Yes OEM classic kit, with cummins recon rods, and cummins new head. Liners set to .014" with .020 repair shim.

3) in febuary we got code high pressure......changed sensor because it was a sudden spike and change lifetimec crank vent box....went from 4.0 at idle to 1.5 at idle, under a load under 10hg...It was weird it because i seen loss on 6 cylinder when cutting it. However after leak down test all even, it was inconclusive to me. I put it back together on the injector. Then it was gone. I had no drop on number 6 and good crank pressure. Okay sent it out for 8 month and throw a code high crankcase pressure and number blow the ring for sure. Very confirmable on diag.

4)RPM 1400-1700 i would predict it lives it's life. it does 65 mountain and interstate is 75mph...30%moutian/secondary roads. i would say

Question: 570k on 500hp efficiency series engine and 10k-12k hrs...not bad?
Division manager was all sad..but i didn't think it was awful but i wished for better.