Blow by catch tank

[TomC]

Has anyone made a collector tank for blow by from the valve cover, block, and air box breathers?  Would like to put together something that collects all in one tank with a ball valve drain to easily drain the tank when full.  Thanks, Good Luck, TomC

[robertglines1]

been several discussed here made from PVC and the like..I just use two detergent(laundry soap) jugs and run hoses in where lid was. Empty at oil change :usually not much in them. wire/bolt in a place away from exhaust.  Bob

[FloridaCliff]

Tom,

Here is what you need.......

http://www.busconversions.com/bbs/index.php?topic=11842.0

[Oonrahnjay]

Not to seem criticizing anyone, but here are a few thoughts based on my experience (which isn't "heavy-duty").

1)  An important thing with a "catch tank" is that it shouldn't allow any possibility of blocking whatever it has been set up on.  Those "breathers" are there to let pressure out and bad things (like engine runaways and blown gaskets) can result if they're blocked.  So be sure that the tubes into it, the setup inside it, and the outlet cannot become blocked.  It's probably a good idea to check that fittings and the cap are kept clean occasionally, too.

2)  If you're getting drops of liquid oil, a catch tank is pretty easy but if what's coming out is a mist of oil, often a catch tank just moves the place that the oil spray gets put. A good way to deal with oil mist is to take Jack's breather tube (as shown in the other link) and put a couple of copper "pot scrubbers" in the catch tank above the inlet tubes but below the breather cap.  They will do a good job of helping condense the oil mist into drops that will fall to the bottom of the tank and not get sprayed out the breather as mist. Don't back them in tightly (see 1, above) -- the open weave will do the condensing just fine.

3)  It is sometimes possible to pull vent air and vapors into the intake manifold but on a diesel you must be VERY careful of this.  Even slight increases in the amount of oil vapor being introduced to a manifold can lead to an engine runaway.

4)  The issue of check valves and similar components has been discussed.  It's important that your breather system is properly setup and maintained to the manufacturer's design.  Don't expect a catch can to make up for the breather system not working as it should. 

5)  Also, be sure that there's not an underlying reason for too much oil being blown out of the engine.  A breather system is meant to ventilate a properly working engine cavity.  If there's a leaking seal or damaged gasket or other mechanical problem, you could be seeing that in the amount of oil.  A catch can might be a valuable way to keep things clean on a healthy engine, but if you have a mechanical problem in the engine, make sure it's taken care of rather than depending on a catch can to hide the problem.

Hope this helps,  BH NC USA