Re: How do you install a catch can?
Crankcase ventilation is via the valve in the rocker cover directly to the intake manifold, and should be drawn back into the engine and reburnt. Unfortunately if you have a lot of blow by ( sad rings, really high boost ) you get a build up of oil in the intake manifold as the oil vapour condenses. If you install the catch can immediately below the intake manifold, the blow by leaves the rocker cover and goes into the catch can and the vapour will be drawn into the intake manifold, and the condensed vapour stays in the bottom of the catch can as oil.
Provided there are no leaks, all vapour should return and burn, and the excess oil can removed and disposed of from the catch can as necessary.
This in no way bypasses any emissions setup on the vehicle. It just prevents oil build up in the intake of a vehicle which might be in need of a rebuild.