how do you fit up an oil catch can?

[oldcorollas]

damn rockets
the exhaust gases that leak into the crank case also contain moisture, but when hot, that moisture should evaporate and be sucked out of crank case back into manifold... unless you have catch can....

you mean moisture/humidity from the atmosphere getting back into the motor? possible, but maybe not a huge threat if the openings are not large.. in stock application the rocker cover is vented to before TB, so it is effectively open to atmosphere anyway.

you mention both pressure and vacuum (crushing?). lines should not squash under pressure, only under vacuum. it is important NOT to seal the system so that no pressure builds up and pushes oil past seals, or pops seals out...it should always be vented to the intake, via an efficient air/oil mist seperator. did your catch can burst outwards or crumple inwards?

fuel filter will nto flow anywhere near enough air, especially after the paper has been "wet" by the oil.... ever tried to breath through a wet towel? the air from rocker cover must have a free path out.

two reasons to get a device between cam cover and intake.
1) catch can if head oil drain design is such that oil pools on cornering and is subsequently blown out.
this problem is worse with tired motors with too much blowby.
2) oil air separator if their is an air/oil mist blown out of the cam covers under throttle.
this problem is worse with tired motors with too much blowby.

and as mentioned, in case something goes horribly wrong and you are just containing an engine hemorrhage.

so.
use big lines for flow. restricting air getting out will cause pressure and leaks.
don't block outlet, plumb it back to intake.
use an oil/air separator in preference to a flashy milo tin.
run line or lines from cam covers to the device, run the air out line to the intake. if in doubt, use another mist separator instead of a filter. filter wets with oil and doesn't flow (try it )
if you have a serious problem, either your engine is rooted, you need to redesign the oil drain in head, or you need a dry sump.

in drag racing (and other forms) higher vacuum in the crankcase gives higher engine output.
the size of a catch can should not affect power (unless it is causing a pressure buildup in the block), ie if the lines are big enough, the size of the can is irrelevant.

catch can is often a band-aid for an engine problem. work otu what the problem is and design the catch system to suit that... just wacking on a catch can is a bit random

[gearb0x]

Mines not sealed, hoses are just jammed in the top of the bottle, its mainly there to keep oil from going all over the motor and onto the track

It used to have a filter on the top of the motor but all it would do would cover the rocker cover in oil

catch can is often a band-aid for an engine problem

Yup! in my case ye old 2TG is in need of a rebuild, just over 100psi on al 4 cylinders. But it still runs and makes power