Lot of blowby after rebuild
08-31-2017, (Subject: Lot of blowby after rebuild ) 
Post: #1
Lot of blowby after rebuild
Hello all, I'm rather new to this forum.

I've been having issues with a lot of white smoke coming from my oil fill cap. The truck is a 2008 Peterbilt 389 with a 550 ISX CM871. When I bought the truck about 8 months ago, it had been rebuilt at a million miles and currently has about 120k on the rebuild. The DPF was clogged when I bought it, I had it mandate'd and the ECM tuned. Since then I've put a turbo on it since before the EGR cleanup it had been leaking oil from the compressor side, so I just replaced it. I get good fuel mileage for what it is, average is 6.8-7.0 with no lack in power. I put a hole in the crankcase breather to relieve some of the crankcase pressure, but I still get a lot of blowby out of the oil fill. I change my oil at 13k, filters every two changes, and I only use up maybe a half gallon of oil every change. I'm not burning any coolant and I don't get any issues with overheating or lack of power.

Any ideas?
Thanks
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08-31-2017, (Subject: Lot of blowby after rebuild ) 
Post: #2
RE: Lot of blowby after rebuild
Its hard to know what to expect unless you know how the rebuild was done. There is 1000 ways to rebuild an engine. They might have rolled in new bearings without doing cylinder packs and called a "rebuild". Do you have a receipt on what was done to the engine?
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08-31-2017, (Subject: Lot of blowby after rebuild ) 
Post: #3
RE: Lot of blowby after rebuild
(08-31-2017 )tlzimmerman Wrote:  Its hard to know what to expect unless you know how the rebuild was done. There is 1000 ways to rebuild an engine. They might have rolled in new bearings without doing cylinder packs and called a "rebuild". Do you have a receipt on what was done to the engine?

Yeah, I have the whole invoice from Cummins with everything that was done. It was rebuilt completely top to bottom, new crank, new head, new pistons liners everything
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08-31-2017, (Subject: Lot of blowby after rebuild ) 
Post: #4
RE: Lot of blowby after rebuild
its possible the rings did not seat but unless you're burning a gallon every three thousand miles cummins won't warranty anything...I would run it and hope they seat...could take 50k miles or so.
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08-31-2017, (Subject: Lot of blowby after rebuild ) 
Post: #5
RE: Lot of blowby after rebuild
You say it was mandated, Do you mean deleted?, if so this is your underlying problem. When you replaced the turbo, was it properly calibrated, along with the turbo actuator?. You can read up on how to do this and many other procedure's on quickserve.cummins.com


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08-31-2017, (Subject: Lot of blowby after rebuild ) 
Post: #6
RE: Lot of blowby after rebuild
(08-31-2017 )cubillos389 Wrote:  ...
I had it mandate'd and the ECM tuned. Since then I've put a turbo on it since before the EGR cleanup it had been leaking oil from the compressor side, so I just replaced it.
...

There are more bad deletes out there than good. Most will destroy your engine in short order, so if you have bad programming, then it will do it again.

Who did the de-mandate work? and when?


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08-31-2017, (Subject: Lot of blowby after rebuild ) 
Post: #7
RE: Lot of blowby after rebuild
(08-31-2017 )Rawze Wrote:  
(08-31-2017 )cubillos389 Wrote:  ...
I had it mandate'd and the ECM tuned. Since then I've put a turbo on it since before the EGR cleanup it had been leaking oil from the compressor side, so I just replaced it.
...

There are more bad deletes out there than good. Most will destroy your engine in short order, so if you have bad programming, then it will do it again.

Who did the de-mandate work? and when?

The new turbo hasn't given any issues, I get about 39-40 pounds of boost under full load. My oil also doesn't start to turn dark for about 10k miles, before then it's more a dark brown than black.

A local guy here in California did it, he sent in the ECM for programming and I am honestly not sure who got it. I've read a lot of things about what the bad deletes are, and for the most part my motor doesn't fall under any of the bad symptoms of a bad de-mandate. It was done in June, maybe 40k miles ago.
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09-01-2017, (Subject: Lot of blowby after rebuild ) 
Post: #8
RE: Lot of blowby after rebuild
(08-31-2017 )cubillos389 Wrote:  
(08-31-2017 )Rawze Wrote:  
(08-31-2017 )cubillos389 Wrote:  ...
I had it mandate'd and the ECM tuned. Since then I've put a turbo on it since before the EGR cleanup it had been leaking oil from the compressor side, so I just replaced it.
...

There are more bad deletes out there than good. Most will destroy your engine in short order, so if you have bad programming, then it will do it again.

Who did the de-mandate work? and when?

The new turbo hasn't given any issues, I get about 39-40 pounds of boost under full load. My oil also doesn't start to turn dark for about 10k miles, before then it's more a dark brown than black.

A local guy here in California did it, he sent in the ECM for programming and I am honestly not sure who got it. I've read a lot of things about what the bad deletes are, and for the most part my motor doesn't fall under any of the bad symptoms of a bad de-mandate. It was done in June, maybe 40k miles ago.

Another victim of a bad delete, who remain's to be stuck on stupid


User's Signature: It's hard to win an argument with a smart person, but it's damn near impossible to win an argument with a stupid person
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09-01-2017, (Subject: Lot of blowby after rebuild ) 
Post: #9
RE: Lot of blowby after rebuild
May have the same problem I had. Polished liners from carbon packed pistons,caused by incorrect injector cam timing retarded 12 thou. My engine had blowby but didn't bun oil, not a measurable quantity anyway.
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