Exhaust brake = Excessive Soot in oil!!

[BigYellowIron]

Has anyone else noticed their oil sooting when running a exhaust brake. I changed my oil after I installed the PRXB and noticed that it was extra black. I turned in a sample (i used Caterpillar SOS since I work for the dealer its free). I think that Cat has one of the best oil labs, we base allot of our repair recommendations off of them. It came back off the scale on soot, Iron and chrome was high also. With soot being high one would expect iron and chrome to be high. I have run a "chip" or a "box" several times but not for more than a day at a time. I cannot blame it on that. My normal driving is 90% highway, so I changed it at 8000 miles and I switched to Amsoil now.



I was trying to eliminate all of the suspects to dirty oil and the exhaust brake is my suspect now.



Anyone else seen this.

 

[Cattletrkr]

I don't think you'll find anyone who uses their exhaust brake more than I use mine. I always have very black oil. Immediately after filling with fresh oil, mine is black when I pull the dipstick.



I've sampled a few times and soot has never been an issue. Neither has anything else for that matter.

 

[Vaughn MacKenzie]

Not sure how an exhaust brake can soot the oil unless it's engaged other than during deceleration. During deceleration there is no fuel going to the cylinders at all so there's no way it can be sooting the oil in this situation. Do you use your brake for warming up or when idling? Does the brake disengage before you step on the throttle to accelerate? Maybe tell us a little more detail as to when exactly it's engaged.

 

[RustyJC]

I could see this if you do extensive idling with the exhaust brake engaged. Although Cummins has recommended this practice on 2nd generation 24 valve trucks to speed warmup and to keep engine temperatures high enough to avoid valve stem/guide sticking and bent push tubes, it does cause flow reversion which can soot up the IAT sensor and probably the oil as well if carried to extremes.



Rusty

 

[Cummins724]

I have the same problem & yes I do use mine to warm the truck up. My oil doesn't get black, but darker brown shades..... still can see through it. I only use Valvoline Blue & Fleetgaurd filters. I am going to get a fs2500 system soon to clean it up.

 

[BigYellowIron]

I have used it to warm up, the ecm will turn it on. Only use it when slowing down. I use it loaded and unloaded. Oil readings was normal at every oil change, until the brake was installed.

 

[jelag]

We've been installing exhaust brakes and engine brakes for 20 years or so..... They are offered on CAT, Isuzzu, Hino, Mercedes, Dodge, Ford, Chev and IH to name a few... . they have approval of the manufactures and on some engines can be ordered that way from the factory... . Some engines can't support engine brakes because of the design so exhaust brakes are fitted to some of these... . Others, like a Cat M10 we have in a IH truck won't accept either, but I a can assure you... . that what happens in the combustion chamber under full HP and Torque applications blasting up a hill..... does more to add dirt to the oil than letting your truck run all night with the exhaust brake on... .

The only path to the oil galleys is valve guide wear, and past the rings in the combustion chamber... . when the brake is on there is 60 psi of back pressure in the exhaust system..... and very little combustion in the chamber at idle conditions..... I can't see where this is a problem... .

For more information on this... . contact tech support at PacBrake, they have been building and selling engine brakes and exhaust brakes for all that time...

 

[RustyJC]

The high exhaust back pressure when the exhaust brake is energized at idle causes flow reversion from the exhaust back to the intake during valve overlap - that's why the IAT sensor becomes sooted up. In addition to the soot remaining in the combustion chamber, this soot is pulled from the intake manifold back into the cylinder on the intake stroke where it can agglomerate in the lube oil film on the cylinder walls. On the power (downward) stroke, the oil scraper rings pull this soot-carrying oil from the cylinder walls back into the crankcase.



Rusty

 

[Vaughn MacKenzie]

I have used it to warm up, the ecm will turn it on. Only use it when slowing down. I use it loaded and unloaded. Oil readings was normal at every oil change, until the brake was installed.

I'm going to venture a guess that the idling is what's sooting up the oil, especially if the engine is started cold then the brake is engaged. With cool combustion and the 3rd injection event there's probably quite a bit of particulates from partially burned fuel recirculating more than once from the scavenging/backpressure effect. With this going on there's probably a fair amount getting by the rings. I don't know how often you use the brake for warming up and for how long, but you might start up like I do by taking off within a couple minutes of starting the engine. Next time you change your oil you might avoid using the brake at all during idle and see if that helps keep from oversooting it.

 

[DerekW]

consider additional oil filtering such as fs2500. but what do you seriously expect you have a explosiong that normally can some what escape when the exhaust valve opens then you make it harder for it to go out the exhaust valve then its gonna find somewhere else to leak the explosion. Few member on TDR run gapless rings and even fewer gapless rings with exhaust brakes. it would be nice to hear from those members and their own experiences.

 

[DerekW]

hey if we ran dry sump oil systems on these things imagine the sealing on the rings and the lack there of in the way of blow by. but its reall rare to find a dry sump cummins 5. 9 only in the racin world my friends. but if dodge would consider it from the factory The power would be nice and the EPA would do alot more moaning but that is towards the other diesel engine suppliers to run dry sump on future vehicles for better emissions.



hey does anyone know how big in microns soot is? I would seriously like to know so I can try to figure out how much wearing soot is putting on these engines. I read some where on the internet ahhhh on morosos website that theres a certain size particle in oil you dont have to worry about



BRB with factual data.

 

[DerekW]

okay dokey here you go thank you come again

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[camsv3500]

I went to the link... it didnt work for application,,