How many people are running oil catch cans in their CA's.

From what i've read CAMS might ask for a 2 litre catch can....which seems a little big. (I'm thinking of not running one at all - execpt I'm not sure if i want oily air running through the turbo.

There is a few ways to do it - see thread below, which ways have people gone and why.

http://forums.nicoclub.com/zerothread?id=137506

Have looked at a few options on this one and presently thinking of running the breather from both rocker covers into a custom catch can with two inputs. Oil / Air separator inside and a mini pod on top. Then block off the fitting on the back of the intake manifold.

Problem is this is not road legal in WA. So will wait till car engineered and liscenced.

Interested in thoughts on above.

Old CAs under boost produce a bit a blowby when thrashed. 2 L sounds big, but a poorly rebuilt engine with a full load of oil might actually need it.

Blocked oil drains on the intake side are the main cause for CA oil issues.

It should mostly be about 'catching the oily air' that is displaced when the oil from the sump is pushed back up the oil drains.

I have put a catchcan in between the exhaust rocker cover and the low pressure intake only. I've left the intake side as Nissan designed it.

My car has been thrashed a little, and I've caught no oil in mine at all. Which is a good thing.

I assume that means you plumb it back in to the intake? (Like this pic)

seems like a weird way of doing it, kind of combining two methods?

i would think most oil would come from the crank case breather, crank breathing so as not to get pressurised by what gets past the rings (but could be wrong)

so in my thoughts i would be putting the crank breather through a catch can if any...

i was looking at the possibility of moving the intake breather to the back of the rocker cover, to make plumbing a lot easier and neater, looks do-able but questionable if it's worth it


{edit} looking at the link people seem to beleive the exhaust side will get a bit more blow by.... not sure why that is?

Yep mildman, that's how I've done mine, which is the closest to what the factory did.

The problem with plumbing back the crank vented air to the intake, is the oil in the hot air... that's what the catchcan should be catching. If you need to be catching oil that's pumped up from the sump...that's a crank vent system design problem.

Remember that you want oil in and around the cams. That's why the breathers need to come from the very top of the cam covers. If you put them at the back, they'll fill up your catchcan under accelleration.

Sometimes when making an engine look pretty, you need to accept some functional compromises.

Cool, thanks dd, it made a fair bit of sense to do it that way. I prefer the idea of not loosing any air out of the system.

A 2 inlet catch can will make for less piping too.

I also wonder why the exhaust cam ends up blowing more oil....what sort of air get in to the cam cover?

yeah dattodude, i agree i did mean relocating the raised section to the back of the cam cover, not just a hole in the back face of the cover

is the catch can completely hollow or does it have a filter to retain some air borne oil?

if it was hollow it may not be very effective

Most of them have a baffle between inlet and outlet, not sure if they have steel wool in the bottom - that would be good though for pulling the oil out of the air.