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DIY Catch Can

PostPosted: Fri Feb 05, 2010 8:27 pm
by pig75
An oil catch can is used where excessive blow-by (leakage past the piston rings) of air and fuel vapor occurs. This creates a positive pressure in the crankcase. Engine manufactures have placed a valve on the engine block which releases this pressure. This valve is known as a PCV (Positive Crankcase Ventilation) valve. During engine operation, blow-by gases, as well as oil mist from the rotating components of the engine, pass through the PCV valve and are routed back into the intake for the engine to burn off. However, some of the oil mist and other products settle along the engine intake and over time form a "gunk." The oil catch can collects the oil mist and condenses the fuel vapors while allowing "cleaner" gases to be passed back into the intake. Typically the blow-by gasses are passed through a wire mesh, which give the vapor droplets something to adhere to.

More can ideas here viewtopic.php?f=19&t=851
Catch can for a 3.1 MU. 2.8 is the same but you will need to weld a fitting to the dipstick tube or manually drain the can.
First on the drain fitting, get a ball that just fits inside the fitting. I just used a ball out of an old bearing.
Then put a dent on the fitting so the ball does not fall out. This acts as a non return to stop any oil pushing up the dipstick tube and filling the can while running, when the motor is stopped the oil will drain back past the ball and run back down the dipstick tube into the sump


On the dipstick tube you need a tee fitting. In this case it was 5/8”x5/8”x1/2” for the drain hose


The can I used can be pulled apart so it can be filled with stainless steel scouring pads and fitted with a tube on the inside so the oil is at the bottom of the can
How the can should look on the inside

Then it’s just a matter of running new hoses from the tappet cover to the fitting with the tube on the can. Then the other fitting goes to the T where the hose went to the tappet cover

Re: DIY Catch Can

PostPosted: Fri May 03, 2019 5:40 am
by pig75