I have a p pumped 24v that I am currently in the process of building, and since the front breather is not a great choice for this engine setup I have purchased a billet tappet cover with 2 breather holes in it. I was also planning on running 2 breathers in the valve cover as well. I have seen several catch cans you can buy that have up to 4 fittings for breather tubes and a drain that allows you to drain the oil back into the crank case. My original thought was to use the fuel pump block off, weld or screw a fitting into it and drain the oil back into the engine, but now I'm curious if this method would work because I'm thinking that drain would be under pressure as well and not drain very well. Since I started thinking about this I thought about how the turbo drains oil back into the block and was curious if the crank case pressures ever have caused any issue for the turbos draining back into the block.....anyone with some insight or experience please chime in. Thanks!

 

My thoughts? Usually what comes out of the breather you don't want back in your engine. Your better off finding a better place to vent it. Someone used PVC over the top of the engine then down the back. Looked kinda tacky, but the idea is fantastic for a couple of reasons. 1, it gets rid of the bottle. And 2, it eliminated the oil loss associated with steep down hill angles.

 

Cougar, I'm not sure you are understanding what I am talking about. a Catch can vents gasses, and drains oil back to the engine. Why on earth would it be a bad thing to put that oil back in your crank case? I hate the idea of blowing oil along the underside of my truck, I also hate the idea of wasting the expensive synthetic oil I use in my truck.

 

I know exactly what your talking about. The reason the current "catch can" makes such a mess is no one ever (or hardly ever) removes and cleans them. It only hold so much oil. That oil collects in the can slowly over time until it starts spilling out the vent holes. So using a "direct to atmosphere" vent will not be blowing oil everywhere unless you have a high blow by engine problem. The reason you don't want to return that oil to the crank case is it's not just oil. It contains contaminates that you don't want back in your engine. Water vapor, acid vapor, and other assorted combustion byproducts that will condense back into the oil you want to drain back into the engine. As far as "expensive synthetic oil", I don't waste my money on them. It comes down to proper regular maintenance. Not how much you spend on it.

 

The "catch can" that is on the front of an engine isn't really a catch can, it's more of a puke bottle. The catch cans I am reffering to will be aluminum or stainless, and have 3-4 AN fittings going to the can. Usually 2 from the valve cover, and 2 from the tappet cover. The can has a breather on top of it and will vent all the vapors out, and it is baffled to allow the engine oil to seep down and drain, through another AN fitting that goes back into the engine. A lot of these have a 40 micron filter on it as well....All engine oil that is being used has a small amount of condensation in it, but just because the oil is trapped in a sealed catch can and returned to the crank case doesn't mean that oil is any worse than the oil being returned to the engine into the oil pan by normal means. as far as synthetic oil goes, thats a personal choice but for me it's cheaper to run it because my oil change intervals are 10K miles and I have had the oil tested before and it has tested fine. I would have to change my oil twice as much if I wasn't running synthetic.....for me it is expensive but it's cheaper due to the longer oil change intervals. I also use Lucas oil treatment and have had great results with that stuff.

 

Rightwinger,
I understand what you are wanting to do and I have been thinking of the same for sometime. I have installed a like can on a newer hemi for a friend. completely sealed unit that was able to plumb and catch the oil before it gets dumped back into the intake passages (great emissions). the Hemi motor doesn't dump that much oil but it stopped it completely from going in the intake system. the oil was caught in the sump of the can and still allowed crank pressures to escape through the oem path to the intake.

so on my truck when i had the engine rebuilt (now have 28k miles) the truck did have more blow by and some oil that was escaping not much loss on 4k mile oil changes. I extended the oem puke bottle hose back along frame to the T-case area. I wanted to relieve some more pressure since the truck was going to be awhile to seat and break in etc. I have seen people do the diff vent mods. I bought a oil cap that has a vent filter built into the cap from www.hoeslidiesel.com
What i have noticed the last maybe 2 oil changes is there is less actual oil in my blow by . its not really making any oily mess on the valve cover. So this did help lower pressure.

Catch can.
I'm still thinking of this. options in my head, taking the dipstick tube and modify it to accept oil to return. oil return from turbo ( like you mentioned) also thought there would be a way to plumb into the factory spot up front run that tube straight up and plumb it into the oil cap just like most after market dual oil filter setups. but between the 2 locations vent it. so you would almost be putting the catch can on top of the oil cap and would drain through the oil cap by gravity/pressure or oil would be collected in can and every so many miles open the valve on the bottom and it drains into the oil cap etc, etc.

I can picture it in my head so lol. I hope you can picture what I'm saying.

 

Fleet guard makes something I think is called enviro guard. Could be wrong on the name though. It is a unit that replaces the original breather and catch bottle, vents the gases and returns the oil back to the oil pan via a secondary oil dipstick boss that is apparently used in other applications. In any case it is on the drivers side several inches forward of the dipstick tube underneath the vacuum pump area, it may be behind beneath a large wire loom. It is plugged with for lack of a better term a freeze plug. You pull it out and the enviro guard has a tube with an oring that fits In there with just a pressure fit. At one time I found the install directions online. It may show or tell exact location of the plug which you could use for your return and must not be under pressure as cummins is using it for the exact same thing you are wanting too.

 

I have a friend that says he somehow extended that tube out and got rid of the puke bottle but plumbed it into his exhaust system.... I'll have to ask him what he did and if it actually works, because I figured the exhaust pressure would go up the tube and create problems....

 

Seems to me that venting the blowby back into the engine would overpressurize the crankcase and cause leaks. Any place you leave open to vent the pressure would be the new oil leak source.
Venting the the oil back to air filter like the PCV valve on a gasser would just oil up your filter.
There was an aftermarket device, forgot the name, that would pressurize your blowby to overcome boost pressure and vent it back into the intake manifold right at the engine.

 

You can easily vent the crank case pressure w/o venting the oil. Most performance catch cans use a small filter similar to an air filter, with a 40 micron bronse screen filter behind it, and then make use of a series of baffles designed to release the pressure but retain the oil. Most likely the oil can be drained back into the engine from many spots, but trying to find the best spot is what I'm dealing with. And from my thinking I would assume that the oil would only drain back into the engine once it was shut down due to no pressure being on the drain line.....