Thoughts on CCV?

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Redrider2911

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So I don't I have my stock draft tube on my tappet cover anymore, I didn't like the smell I was getting in the cab and the amount of oil it was dripping. I tried to set up a venturi crankcase vent from a valve cover to the downpipe after the turbo, I found that I had too much back pressure there to create good vacuum because of some of the bends I had to make down stream. So now I am back to venting under the hood, and with a less-than sealed old Willys cab, the smell can get uncomfortable.

SOO. I was at a buddies shop the other day and we were checking out his drag race motor he was putting together. He opted for a crankcase vacuum pump, thing is supposed to pull like 12" of vacuum. This also supposedly aids in at least an additional 15hp as well as keeping seals in place during higher RPM/higher blowby conditions.

This got me thinking a little bit, I don't want to run a vacuum pump; they are expensive and take up more space than I can spare, plus I would still need to vent those gases somewhere. Of course, our intake manifold does not have any vacuum like a n/a motor. BUT post-filter, pre-turbo there should be plenty of vacuum. I believe Cummins spec for air filter restriction before replacement is something like 22" of vacuum.

I did more searching and found that this is actually common practice with newer diesels, replacing the road draft tube setup. It seems a lot of people are eliminating these due to complaints that their turbo and intercooler are getting coated with engine oil? It might sound counterproductive to want to add this setup to an older truck, but I believe it has its uses; proper evacuation of crankcase gases and maybe even a little increase in power though most likely negligible.

What about running the crankcase vent through a good catch can first, then into the pre-turbo tract? Your ideas and opinions are much appreciated.
 
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I personally don't see the huge issue with the motor ingesting its own blow by, to an extent.

That said this is how I vent to atmosphere. It's messy and I have to clean everything every couple weeks.
 

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Keep in mind, if your catch can cannot keep up with oil vapors, it will overspeed.

A good catch can with enough ventilation, like 2 or 3 from tappet cover and 1 or 2 from timing cover, all 5/8 or 3/4" will be adequate to evacuate vapors to atmosphere without much, if any oily smell.

If your motor was recently rebuilt, it will take some break in time to seat rings well, and that will take care of a good chunk of the issue.


The exhaust venturi is a very feasible one, however, will not work at low speeds at all.
 
That makes sense, pretty much saying that if your crankcase gases discharge at too high of a velocity that there will be more chance of oil staying suspended, even through a catch can.

So I know there are different kinds of catch cans. Cheap ebay ones that are literally just hollow cans (crap), ones that have multiple baffles and screens to strip the oil out of suspension, and even ones that have some type of foam or steel wool filter media. Common complaints include not enough oil separation out of the baffled ones, and too frequent of service time out of the filtered ones due to clogged media.

What about discharging the crank gases into a longer tube that goes almost all the way to the bottom of the catch can, then pre-fill the catch can with 1" or so of oil. As the gases pass through, any liquids will stay with the oil at the bottom.

Yes, I would agree with you that most of my blow-by is because of the fresh engine. It actually seems to be getting better every day.
 
Not really answering your questions, but switching oil brands can dramatically reduce blow by smell, especially rotella stinks. You can also plumb the blow by directly into the exhaust down pipe as long as you're not running too restrictive of mufflers.


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That sounds like a runaway risk, especially if you blow a head gasket and pressurize the crank case.
 
Cummins610 said:
Not really answering your questions, but switching oil brands can dramatically reduce blow by smell, especially rotella stinks. You can also plumb the blow by directly into the exhaust down pipe as long as you're not running too restrictive of mufflers.


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In my first paragraph I already addressed this. Wont work with my setup.
 
Venting the crankcase to the intake of the turbo just doesn't sound like a good idea, catch can and all. I've half filled a catch can before on a truck that was run hard, I've since added another can and breathers. If you hurt a piston or anything to pressure the crankcase and blow oil to your catch can and it makes it to the turbo is what I was talking about.
 
I wouldn't even think about it personally. It will coat your turbo and your intake tract. Compounds are going to pull oil. It will make a mess and you won't know if it's ccv or the turbos leaking or both.
 
jasonc said:
Venting the crankcase to the intake of the turbo just doesn't sound like a good idea, catch can and all. I've half filled a catch can before on a truck that was run hard, I've since added another can and breathers. If you hurt a piston or anything to pressure the crankcase and blow oil to your catch can and it makes it to the turbo is what I was talking about.
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A friend of mine melted a piston in a 12v and it blew the oil cap off the valve cover and shot oil everywhere.

Lots of air looking for a place to go is going to bring some oil with it, I'd be concerned unless you have a very good drain back catch can.

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I ran a vacuum pump on my first engine. Pulled through a catch can, then vented out the exhaust pitot. All I can say is have a really large catch can. A vacuum pump on a engine running 90psi of boost can suck a lot of oil.

With the new engine, I replaced the oil filler cap with a filtered breather cap. Then I have a 12n hose on the tappet cover that 90s up as far as possible, then turns a 180 down to a baffled catch can. And, I run a 7/8" vent hose from the rear turbo drain inlet, forward and up to another baffled catch can beside the radiator. That can I sometimes vent to an exhaust pitot, sometimes I don't. All that together works well. Normal driving won't put much oil in the cans. A few passes at the track will put oil in them though.

In your case, some of the ebay cans aren't that bad, but if I were you I'd make my own. I make mine out of 4" tubing, then add a few baffles inside, plus a couple of the stainless steel scrubbing pads, and finish off with a plenum to slow the flow. There is also a perforated baffle separating the flow from the reservoir. Use the biggest hose and fittings you can make work. Pretty inexpensive to make except for the bungs.

I would not vent anything in front of the turbo. With a engine running low boost you can get away with it. With running 75psi+, the chances of blowing out oil are much higher. Taking turbos apart and pulling an intercooler to clean it is no fun.
 
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Kind of on subject, what do you guys think about re-purposing an old oil bath air cleaner for a catch can? Maybe not for this project, but something more "rat rod" like.

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Poulina said:
I personally don't see the huge issue with the motor ingesting its own blow by, to an extent.

That said this is how I vent to atmosphere. It's messy and I have to clean everything every couple weeks.
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The thing I don't like about venting straight to the intake, is that it can result in preignition if you have major engine problems, making major engine problems even worse.

J-Pipes said:
Kind of on subject, what do you guys think about re-purposing an old oil bath air cleaner for a catch can? Maybe not for this project, but something more "rat rod" like.

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That could work well I think. Maybe even for catching oil and venting to the turbo intake. I think I would put a electric valve on the bottom of the oil cup, so it could drain back to the pan when the ignition is off.
 
J-Pipes said:
Kind of on subject, what do you guys think about re-purposing an old oil bath air cleaner for a catch can? Maybe not for this project, but something more "rat rod" like.

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Click to expand...

I modified an old power steering reservoir for future use. Would be along the same lines. Welded some stainless fittings into it and bought some stainless pads to help catch the oil vapor.
 
The thing I don't like about venting straight to the intake, is that it can result in preignition if you have major engine problems, making major engine problems even worse.


Preigniting oil vapors from the crankcase in a compression ignition direct injection motor? I would think you would need a hole in a piston to get enough cumbustable material back into the intake charge to have enough to cause a detonation issue?
 
jasonc said:
Venting the crankcase to the intake of the turbo just doesn't sound like a good idea, catch can and all. I've half filled a catch can before on a truck that was run hard, I've since added another can and breathers. If you hurt a piston or anything to pressure the crankcase and blow oil to your catch can and it makes it to the turbo is what I was talking about.
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The way your post appeared, it looked like you were responding to having the case vented to the exhaust.
Nbd

Something smart goes here
 
Poulina said:
The thing I don't like about venting straight to the intake, is that it can result in preignition if you have major engine problems, making major engine problems even worse.


Preigniting oil vapors from the crankcase in a compression ignition direct injection motor? I would think you would need a hole in a piston to get enough cumbustable material back into the intake charge to have enough to cause a detonation issue?
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Yes, it has to be a major piston problem. Hole, Crack, severely scored, ect. I've seen it happen and things get worse as a result.
 
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