Crankcase vent

raydav

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I acquired an 84 E350 with a 460/C6 in 1993. Over the next few years I replaced the C6 with an E4OD and the Dana 70 single with a Dana 70 dually. In 2005 acquired an 89 E350 for it's 7.3 IDI. I later redid the IDI fuel supply system including replacing the filter with a Racor on the frame. In 2012 I added a turbo that was intended for a 2000 PSD.

There are a few pics here.
https://goo.gl/photos/LJNV4esgmYmSzKdL8

The original IDI crankcase vent is just out of the valley, into the CDR, and into the intake. It is out of sight and out of mind. When I first removed the air cleaner I noticed that the intake was wet with oil. It has been said that is to be expected.

After I installed the turbo I turned the CDR around and setup to run the CDR output to either the air, the turbo intake, or the tail pipe about two feet after the turbo - there is no muffler, a turbo is listed as a muffling device.

I settled on piping the output of the CDR to the turbo input. The CDR allowed oil to pass - as predicted - before the turbo was installed and continued to pass oil after, so the intake system from the compressor to the intake was wet.

I just installed a Mann oil separator. The initial system was valley to Mann to a catch can. I ran a few errands and in about fifty miles the can had seven ounces of oil in it. And the output of the Mann had no signs of oil.

So I have some data points. One, the engine throws out a lot of oil from the valley. Since The engine has never used enough oil to really notice, the CDR has been putting most of the oil back into the crankcase. The Mann is completely effective at separating oil.

Since seven ounces of oil in fifty miles is too much to deal with in a catch can, I ran the drain of the can to the turbo oil scavenge pump which is on the frame to the rear of the turbo. And no you cannot gravity feed the drain to the pan. It is crankcase pressure that pushed the oil out of the valley, and it is that same pressure that will not only prevent oil from draining into the pan but will pressurize the Mann and prevent it from accepting valley oil.

However, with the Mann only system, the oil traveled a foot and a half from the rear of the engine to the Mann at front of the engine, then about ten feet to the scavenge pump, and then ten feet back to the front of the engine where the oil is returned. Since the CDR removed most of the oil I reinstalled it. Now the Mann only needs to deal with the oil that passes the CDR.

Right now the Mann output goes to the air so I can monitor it - it remains dry.

There are two hills near me that I use for performance comparisons. This is not scientific, but it seems that a diesel engine runs better on diesel fuel than it does on crankcase fumes.

Would you like a dry intake?
 
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OLDBULL8

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Seven oz. of oil is a lot in 50 miles.

But when you installed the turbo, did you punch a few 1/4" holes in the valley pan baffle for the oil to drain if the valley pan has never been replaced since about 92.
 

raydav

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Seven oz. of oil is a lot in 50 miles.

But when you installed the turbo, did you punch a few 1/4" holes in the valley pan baffle for the oil to drain if the valley pan has never been replaced since about 92.

I don't believe the baffle has ever been replaced.

Just before I installed the Mann I punched a single, quarter inch hole.
 
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