Theroretical reason for a generic vented can. Cheap way to prevent crank case pressure and help save engine seals. Does not properly address PCV system, pulling vacuum, emissions, smells, or potential oil hazards in bay. Advantage, super cheap, generic, and if all you want is to prevent losing a rear main, or front seal, assuming the lines and filter are big enough, it will do that, at the expense of other items such as your AC/Heat being full of fumes.

Great for dragrace cars that make a few passes a day, then stuff gets emptied, checked. Not so good for road race people or daily drivers.

Also be aware, just because it has a filter on it, doesn't mean it is a vented can. The MM have a filter, but also a one way valve that only allows it to vent under excessive crank case conditions, basically if something goes wrong. Then again MM cans can be setup vented, or not depending on use and application.

If you don't mind smells, and don't mind that it may spray oil, and don't want or need a functioning PCV system, then just hook what you have up.

 

No combustion engine should EVER use a vented crankcase or see atmospheric pressure. Not a race car, not a daily driver, none of the above.

ALL Wet-sump application's call for a crankcase pressure of approx 1 to 3" of Hg (1 to 3 inches of Mercury of vacuum)

You can measure crankcase pressure using a 2-bar map sensor (for typical data logging) or using a traditional gauge (use something which can read inches of water for resolution)

To understand the PCV system, start with the 1 to 3" Hg of vacuum and figure out how to create that pressure drop inside the crankcase.
A. ALL OEM Engines use a Post-air filter, fresh air inlet for WOT which depends on the air filter post pressure drop to generate a WOT Vacuum of 1 to 3" Hg
B. ALL OEM Engines use a PCV valve located on a hose between the intake manifold and crankcase in order to derive a Cruise/Idle Pressure drop of 1 to 3" Hg (idealy)

By adjusting post air filter pressure drop and PCV valve orientation/use/orifice you can effectively achieve a crankcase pressure drop of 1 to 3" Hg In any wet sump application

If you FAIL to achieve the necessary wet sump crankcase running pressure of 1 to 3" Hg then any combustion engine will:
1. Begin to seep engine oil from every seal (valve cover, front/rear mains, etc...)
2. Suffer from reduced piston ring performance (Blow-By Increases non-linearly with crankcase pressure)
3. Incur reduced Engine Oil Quality (the engine will wear and tear more frequently)


To put another way,
PCV is essential in every application, because:
1. low pressure pulls light chain hydrocarbons out of engine oil
2. rapid evacuation prevents oil contamination
3. low pressure enables fully intended piston ring seal function
4. low pressure reduces windage, gobular interference, and flattens rivults (too low and it can starve wrist pins for oil as a testament to its effects)
5. low pressure prevents oil leaks and seal blow-out, helps keep oil out of seals
6. low pressure keeps oil out of the engine's oil baffles and intake

more reading
https://zilvia.net/f/showpost.php?p=...2&postcount=30
https://www.sr20-forum.com/informati...on.html?page=1
fluid mechanics book pictured
https://www.corvetteforum.com/forums...post1599127968
http://www.nsxprime.com/forum/showth...=1#post1862819