Are CR's prone to breaking rings

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Nov 22, 2007
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So I just got around to pulling this 06 down. Has a burnt piston which I knew. But on multiple cylinders it has broke rings. The engine has 200k on it. The carbon between the rings is as bad as I've ever seen. Even on a industrial 12v's aren't this bad. That's on all the pistons not just the ones with broke rings. Are these engines prone to breaking rings and carbon issues?
 
Seems that the 06MY engines are the most prone to either broken rings, or dropped valve seats, or both.
 
Is there a reason for it? Stock tuning or bad rings?
 
I dont know why, but there may have been a bad batch of rings....Ive seen more 06's carbon up and subsequently break the rings more than any MY of the CR.
 
I was told by weston that the 06's are prone to rings breaking. He suggested changing back to the 03-04 re-entrant style piston bowl.
"Those engines are notorious for breaking rings."
"Go with the '03-04 piston, long story short there is a reason the later bowl design was phased out of production for the 6.7L on road application."
 
Well being that the non-re entrant bowl was used for 3MY's but the 06MY is the biggest culprit...I'd say that you only got half the info.
 
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I'm sure there are other reasons. Weston didn't get into all the specifics of the issues with that style piston. I have a buddies 06 that has a good bit of blow by so we are going to rebuild the engine and go with 03-04 pistons.
 
Wouldn't changing to earlier pistons be changing the bowl design and subsequently warrant using different nozzles to accommodate them?

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TX_5.9 said:
Wouldn't changing to earlier pistons be changing the bowl design and subsequently warrant using different nozzles to accommodate them?

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Yes, the nozzles would need changed.

As far as certain engines breaking rings, in my pile of 5.9s I have been tearing down, I have 2 '03-early '04 engines with broken rings, one broke them fairly early on and they kept running it for MANY, MANY miles.
Now it has TWO distinct ring ridges and I doubt the block would bore .040, it's THAT bad.

I still have 4 or 5 more 5.9s to tear down and about 3/4 of a dozen 6.7s to go through.
I may post some carnage pics at some point.
There's some pretty nasty looking stuff in that pile. :evil

Mark.
 
Yeah....carnage pics are always fun look at. :)

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I bought an 03 a while back that knocked and found it had all the top rings broke (every cylinder), no history on it but it had 145k miles all stock.
 
You know what breaks rings? Heat resulting from dirty air filters, boost leaks, tuners. I've seen it more in trucks that had to work for a living. The HPCR fuel system expanded the window for failure due to incomplete combustion.

If I had to guess, I'd say it has something do with Cummins engineers needing to turn up the wick on exhaust temps to burn off NOx with the strict emission standards looming pre EGR and DPF on the Dodge.

[ame="http://en.wikipedia.org/wiki/NOx"]NOx - Wikipedia, the free encyclopedia[/ame]
 
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All years have problems . Early tend to break and run a long time, late style tend to torch pistons when rings break. I believe it is several things one the ring moved up on the piston 2 the hotter cylinder temps and 3 the cr system allows lower rpm lugging causing ring flutter
 
In the 1-2 FULL motor rebuilds we do a WEEK, on average 95% are broken rings. They tightened up the ring gaps from the factory. And with the high temps from these motors, as the cylinders start to shrink and piston starts to swell, they end up touching, and breaking.
 
Snedge said:
If I had to guess, I'd say it has something do with Cummins engineers needing to turn up the wick on exhaust temps to burn off NOx with the strict emission standards looming pre EGR and DPF on the Dodge.
Click to expand...

turboram said:
I believe it is several things one the ring moved up on the piston, two the hotter cylinder temps.
Click to expand...

Viable reasons. The '04.5-07 piston was designed to keep the soot on the flame front, as Jeff said to reduce NOx emissions.
 
I thought I read somewhere that the 06 cylinder heads flowed better from the factory; any truth to that?
 
I just rebuilt an 06 with broken rings in #1 and #6. It broke both comp rings.
 
So to my original reasoning for asking. How is this fixed? Can you tune this issue with the cylinder temps out to make it live longer? Is there a piston for these that drops the ring down further. Would a standard 24v VP with the bowl opened up be a viable option?
 
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