So why does somebody need an Oil Catch Can Tank ? The reason is, that the valve rings do not create a perfect seal. If they did the pistons would not be able to move up and down. Because there is a tiny gap between the cylinders walls and the pistons, a little bit of pressure is able to escape into the valve cover area and crankcase. At the same time burnt oils are also escaping into the valve cover area. This is called “blow-by”. The contents are nasty and will eventually make its way into the PCV line and Breather. The PCV line will recycle these burnt solids back into your intake manifold which will increase the level of carbon solids, and reduce your octane levels. For a boosted setup with turbo and supercharger, the Breather line will recirculate some of these oils into the intake which will go into the intercooler. Of course, the intercooler works best when the interior surfaces are nice and clean. When the breather line returns any fumes with oils into the intake, this will start to coat the inside of the intercooler with oil, and reduce the heat exchange efficiencies.
So, the simplest solution is to insert an oil catch tank can into each line, this gives these heavy oil solids a place to enter and pool. There are many shapes and sizes, and even different configurations which are closed-loop, and open loop.
There are various negative effects of not having a properly designed Catch Can installed and allowing excess oil vapor contaminates the intake system from the stock PCV system – such as:
• Throttle body and/or MAFS (Mass Air Flow Sensor) malfunction or failure.
• Air filter, intercooler (if equipped) and intake ducting contamination if oil pools and run back out the intake system after engine shutdown
• Reduced octane of the air/fuel mixture, which can cause detonation and the ECM (Engine Control Module) to retard timing, thereby reducing engine power.
• Excessive carbon build-up on valves, piston crowns, combustion chambers and spark plugs. This also increases the chance of detonation and power loss.
• Increased emissions & possible contamination of catalytic converters and oxygen sensors.