. . .. The crankcase.

A Preface: The following is based solely on what I've learned through the years of messing with infernal combustion engines so use your imagination where needed.




Folks, you may know most infernal combustion engines have some sort of a crankcase ventilation system. It's predominant purpose is to allow "Blow-By" gases from the compression and combustion cycles of a given engine a means of escape. There are other, less obvious reasons as well but still just as important.

The majority of these gases come from leakage around the piston rings.


They way a piston ring typically works is by taking advantage of the pressures developed with the piston's movement in the cylinder. Said pressure gets in between the ring and the bottom of it's groove in the piston. The way the ring sits in the groove with the piston's upward travel results in the gas pressure pushing the ring outward, against the cylinder wall. That is basically what make it work. The greater the pressure, the greater the force exerted on the ring.
The effective force is directly related to the pressure difference between the high-pressure side (P1 shown below), and the low-pressure side (P2 as shown below) of the ring. So not only increasing the high-pressure side makes a better seal. Reducing the pressure on the low-pressure side of the ring is just as effective. A good illustration of this applied in the automotive industry are the Big-Dawg racers who run a vacuum pump on the crankcase.





Yeah, well, can you make it stop leaking oil?


As of this writing my heap's going on 228,000 miles. While it runs very well and some recent work with the head off revieled the typical "Cross-Hatch" pattern still evident on the cylinder walls, I did notice a lot of slop in the way of sideways piston movement while at the bottom of the bore. Regular expected wear no doubt. With that I would expect an increase in blow-by as compared to new. Here I've gone and made it worse with increased boost exaggerated with water/methanol injection.

It gets to the point where the crankcase pressure can overwhelm the OEM venting system. Not only is the crankcase pressure going up forcing oil around engine seals, but the increased gas flow through the OEM venting system forces a lot of oil mist and vapors through and out of the crankcase making a mess of the truck's underside.


So what can we do about it? MOD IT!!



The OEM 12 valve CTD is vented through the block's lifter valley cover. The vent itself amounts to a 3/4" pipe sticking out the side of the cover. Any entrained oil mist is (hopefully) caught by simple baffling (Part no2).





Catching the oil mist is accomplished by way of "Impingement". The oil mist particles are captured by placing something in the flow where the droplets impinge or impact with it. Like filtering air with a stainless steel scouring pad found in the kitchen. As in our engines, the same can be accomplished by abruptly changing the gases direction of travel. Most often, the oil droplets can't make the turn and collect on the wall of the turn if you will. Gravity has the collected oil droplets drain back into the crankcase.


So how can we have additional venting capabilities without blowing oil everywhere? Here, you have a number of choices available.

Some simply add a common Universal type Breather Assembly to the valve cover(s) or perhaps the OEM 1st Gen oil fill tube.





Dodge/Cummins went to a different method with the 24 valve engines. It works better in catching the oil mist as compared to the earlier version (There's folks who might debate that!) by using a strainer much like the scouring pad.





Dodge/Cummins moved the 1st Gen's oil fill from the front gear cover to the valve cover and placed the new crankcase vent where the oil fill had been.





It appears that the new design is not 100% effective at catching all the oil mist as the standard OEM install includes a bottle to catch the big stuff that makes it out. Periodic/routine maintenance has one empty the bottle when needed.

Still, the newer design vent can be combined with the original for a great improvement over stock capabilities.

 

Another option is to install the crankcase vent as is used in Case/International tractor (Cummins) engines. In this application, the vent/breather is mounted to the top of two valve covers.





The associated Breather assembly bolts to the top of the cover.





The way the cover and breather are made, the flow of oily gases must flow through multiple turns on it's way out. Impingement of the oil occurs all the way. The oil collected by the baffles of the breather are drained through that little pipe seen in the center . . . .





It collects with the oil caught by the initial baffles of the cover, and are drained back into the engine through a pipe in the bottom of the cover . . .





If you go this route, in addition to the cover and breather, you'll need some additional hardware to nail it all together.
NOTE: You 1st Gen folks can use the original OEM valve cover bolts as they are correct for this application. It's my understanding the 2nd Gen 12v crowd may have different OEM bolts that don't fit quite right. It seems they can get by with adding the appropriate washer. You'll need three bolts and an O-ring type seal for the breather, and two bolts with seals for the dual cover. The stock/OEM valve cover gaskets normally used seal the cover to the head.





The assembly is straight forward. Simply press the O-ring into the groove on the underside of the breather. You'll notice in the following image, the bolt hole seen in the upper/right appears to have some pipe sticking out compared to the others. It in fact does and I assume it's for the purpose of installing the thing with the outlet correctly oriented in relation to the engine. You can swap that thing to a different hole if you want to have the outlet point toward the front/left or the rear/left (default) of the engine. Pending where you place the cover, you can orient the outlet so as to point directly to the right/center side of the engine provided it doesn't bump the air intake horn.





Also note that when using the dual version, you'll need to keep the injector lines in mind as where they pass from the injector pump over to the injectors, there may not be enough room for the bridge of the dual cover to fit over them.




As usual, I went nuts and initially started with supplementing the OEM side cover vent with that from the 24v. I then added two the the dual cover vents to that.





I connected the 24v vent with the OEM vent using 3/4" hose, wyeing the two together and on out. The two dual valve cover vents connect to a second 3/4" hose.





The two hoses run down the driver's side of the engine, above and outside of the frame rail there, and on to just inside and behind the driver's front tire.

 

I know, perhaps it's a bit much, but I expect the blow-by to increase as I plan on running with a higher boost figure in the not too far future. With that, I don't expect to have any oil leaks as a result of excessive crankcase pressures. We'll see.
Still, at this point, things work well enough that it appears that coming from the two vent pipes has a LOT less oil entrained with it. I look forward to a cleaner underside. I'm even considering routing the vent gases to the engine air filter box. Maybe.



If you're interested, the 24v crankcase vent can often be found on E-bay. NOTE, you 1st Gen folks will need to relocated your oil fill though. I simply cut the top of the OEM fill tube, drilled the right sized hole in the front valve cover and epoxied it there.

If you want to run the Case tractor vent, you'll need:
1 - Dual Cover P/N 2830784
1 - Breather P/N 2852531
1 - O-ring Seal P/N 2852028
3 - Cap-Screws for the breather P/N 4899092
2 - Valve Cover Bolts 4895214 (1st Gen use OEM)
2 - Valve Cover Bolt Seals P/N 3935449

NOTE: the above part numbers are a combination of Case IH & Cummins part numbers as used by these folks http://www.messicks.com/default.aspx. Doing a search of these forums as well as the lessor Cummins diesel websites will present with similar numbers.
Others who've done the same mod may be able to chime in with more.




I hope this helps those interested in such.

 

Ever thought about an e-vac system like they use on high horsepower gasser motors? Would it work right on a diesel?

 

Even if that don't help a thing, it just looks COOOOLLLLL


Another good job; you can consider yourself an asset to our community.


Besides the cool factor, what is the advantage of the double-cover vent, as opposed to the single-cover vent ??

Are the vent-covers the same size, double or single ??



One other point, I noticed the hose said "heater hose"; I used a piece of heater-hose on a diesel-tank vent and it got spongy and swollen in less than three months; do you think that hose will hold up to oil vapors ??

 

is this another sticky? because i think so...you never know what mod is next.

 

I don't know why it wouldn't work. I'd be surprised if the some of the Big-Dawg Diesel's didn't use it. Perhaps those who know better will chime-in.

The bottom line is any gases that need to vent must first get by the valve push-rods. A tight fit I suppose. A single has just two, a double would have four.
From what I've seen, the breather assembly is common to both single cover and the dual cover.
In a perfect world, the only thing going through the hoses would be water vapor and combustion gases. We'll see.

 

I would like to see what the single valve cover with breather looks like or a part number.

 

Ditto on that, anyone have a picture of one of those?

 

Naturally I can't find the thread that mentions a possible single cover deal. I think it's over on TDR.

 

My truck is stock but I want one. Would it do anything for a stock truck?

 

It only took Chrysler 20 years and government regulation to come up with a completely closed crankcase ventilation system on the 2008 6.7L Ram diesel. The new oil vent filter is replace at 60,000 miles, no more oil dripping on the roads, thanks to the Feds.

 

How about hooking the valve cover breather up to the vac pump ?

 

I forgot about that.

It's my understanding that our vacuum pumps exhaust into the crankcase . . . another source (albeit small) of gases out the pipe.

 

is there any benefit to having the vented vapor routed to the intake manifold, like a PCV system, and burned out? I get tired of smelling oil...
- Sam

edit: my bad fellas - I was surfing the how-tos and after I replied I realized this is the thread tagged at the end of the post by 1985cucv. Sorry for the double-tap.