Oil Catch Can Question

[the.planetary.gear]

I was wondering if there was a tutorial on installing oil catch cans. It seems rediculously straight forward. I want to make sure however that I'm not overlooking anything or need to watch out for anything.

[240sxvaj]

yes it is straight forward. the oil catch can should have two holes you can use which ever for in/out. plug the line to valve cover and into oil catch can, plug the other line from the catchcan to breather(filter), or in between turbo and maf. i think i'm clear?

[krazydriver]

^ um.... no! that wouldn't really let the catch can serve it's purpose.

The purpose of the catch can is to collect blowby from the PCV system to keep it from going into the intake manifold and being burnt.So you need to find your PCV valve. Factory there is a hose that connects this directly to the intake manifold, instead connect a hose from the PCV valve to the catch can, then a hose from the catch can to where the PCV valve connected back to the intake manifold.

This way any blowby is first pulled through the can, where the particles can settle out, then the air is pulled back into the engine and burnt.

If you have a turbo car you need to do some interesting hose configurations. On my car the old PCV valve was drilled out and runs from there to the catch can. The other opening on the catch can runs to a T. From the T one hose goes back to the intake manifold with a 1 way check valve in place so that it will suck into the manifold under vacuum, but do nothing under boost. The other open end of the T is connected by hose, with a check valve, to a fitting before the turbo, this way the vacuum created between the air filter and turbo will suck the blowby into there under boost conditions, while not allowing airflow under vacuum conditions.

Hope that makes sense!

[the.planetary.gear]

Thanks. Thats EXACTLY what I needed to know. I appreciate the information. I don't have a turbo car yet. I'm trying to gather all of the information I need so that once I have all of the parts I can just start putting things together, without having to stop and do research. Then build a little. Then stop . . . etc.

[s13-t]

pictures please!!!! or a diagramn or somthin. trying to figure out where the best place to install it and what to hook it up to.

i have a s13 blacktop sr20det with a breather on my T already oil stained....

[s13-t]

ok i think i understand....this is what i have...and i need an oil catch can to go t the T where the breather is, then the other end of the can goes to my intake?

[480sx]

The way you have your PCV system rigged right now is called a free air crank case vent. IMO its pretty useless and completely defeats the purpose of a PCV system. IDK how that caught on as a good idea but its.. not.

You want to get rid of that breather and attach that fitting on your valve cover to your turbos air intake. This will suck the blowby gases out of your crank case and keep your oil cleaner, longer.

[240sxvaj]

yes it is straight forward. the oil catch can should have two holes you can use which ever for in/out. plug the line to valve cover and into oil catch can, plug the other line from the catchcan to breather(filter), or in between turbo and maf. i think i'm clear?

-------->hooooldd, i think i'm okay, i understand the point of it just suck at explaining it. i just hate being corrected

thanks! krazydriver

Modified by 240sxvaj at 1:39 AM 7/17/2008
Modified by 240sxvaj at 1:39 AM 7/17/2008

[240sxvaj]

^ um.... no! that wouldn't really let the catch can serve it's purpose.

The purpose of the catch can is to collect blowby from the PCV system to keep it from going into the intake manifold and being burnt.So you need to find your PCV valve. Factory there is a hose that connects this directly to the intake manifold, instead connect a hose from the PCV valve to the catch can, then a hose from the catch can to where the PCV valve connected back to the intake manifold.

This way any blowby is first pulled through the can, where the particles can settle out, then the air is pulled back into the engine and burnt.

If you have a turbo car you need to do some interesting hose configurations. On my car the old PCV valve was drilled out and runs from there to the catch can. The other opening on the catch can runs to a T. From the T one hose goes back to the intake manifold with a 1 way check valve in place so that it will suck into the manifold under vacuum, but do nothing under boost. The other open end of the T is connected by hose, with a check valve, to a fitting before the turbo, this way the vacuum created between the air filter and turbo will suck the blowby into there under boost conditions, while not allowing airflow under vacuum conditions.

Hope that makes sense!

Okay i have a ka-t, soo all those pictures that i seen where it goes from the pcv vavle to catchcan and catch can to intakepipe before turbo is wrong? I'm confused now. Because from what i remember stock ka's pcv vavle only connects from vavle cover to intake right before intake manifold. OR am i right and you're talking about a different car? And sorry my first post was vague. also of course the catch can have to sit a little lower than the valve cover. Correct me if i'm wrong.

[krazydriver]

Alright, I am talking about KA. What i posted before is how i did mine.

First thing to realize is that the PCV vents the crankcase, NOT the valve cover. Reason being you get blowby in the crankcase.... if you've got it in the valve cover The valve cover breather NEEDS to be able to breath either from the intake piping BEFORE the throttle body if you have a MAF, or if you've got a MAP system just put a filter on it.

Therefore where the PCV system exits the crankcase, you need to put the catch can in line between the crank exit and wherever your going into. The factory PCV system hooks directly back into the intake manifold AFTER the throttle body (this way it sees constant vacuum). Only problem with this is on a KA-T there is boost in there, and pressurizing the crankcase is not something you want to do, seals *could* pop out, but pretty much it's not venting anymore and your oil quality goes to hell.

As i described before, using check valves you can create a system where under vacuum the air coming through the PCV is pulled through the intake, with another hose connected between the turbo and filter for boost conditions. This is the ONLY time that location(turbo - filter) will see vacuum, so if you have just one line hooked up between the turbo and filter.... your crankcase isn't really ventilating at all.

Here's a pic of my setup.Pretty much there is a fitting off the block where the PCV exits that goes up to the catch can. The catch can goes to the T right by the throttle body. One hose of that goes with a check valve oriented so it is only open under vacuum in the intake, the other goes between the filter and turbo where there is only vacuum under boost.

I hope this explains what i'm trying to say a little better.

[240sxvaj]

WOW. i'm such a noob. honestly this is the first picture that i see with the catch can being hooked up this way, maybe because everyone else i see is running maf like me. can you get a close up picture of where it is connected to by the manifold? Also i have the same catchcan.

[krazydriver]

i can't get in there to take pics, there's no where near enough space.The factory PCV comes out from a small box thing right behind the alternator. It's NOT easy to get to.

For the manifold, i just routed the hose from the T back into the factory 4-1 fitting so that it feeds into all 4 runners.

If you look at the parts explosion in the FSM you can see what i'm talking about. I had my manifold off earlier this year, so i took the time to plan all this out before i put it back on.

[neverlift]

krazy setup bet it works wonders

[480sx]

The valve cover is an extension of the crank case. So, if you have a vac source on your valve cover it will keep your crank case clean as well.

I think a breather defeats the purpose of a PCV system. IMO, you want a slight vacuum on the whole system(as designed from the factory) so when you get blowby gases(positive pressures in the crank case), the slight vacuum created by your pcv system removes those gases and equalizes the pressure of the crank case. If you have a breather, your pcv is going to try to suck out the air with least resistance.. IE, the breather filter on your valve cover. So, your really not removing much blowby gases at all, your just sucking in fresh air down to your PCV valve.

I know with my vacuum PCV setup my catch can was 40 percent full of FUEL after 500 miles, and its not a small catch can at all. I had a blown injector driver that was washing my cylinder wall.... But thats besides the point. Under the worst case scenario, my setup worked wonders.

[krazydriver]

dude, the factory system has a breather. regardless of the "easiest" airflow, it will have to suck the blowby and/or windage out of the crankcase to allow that fresh air to flow through.idk mine works, and i honestly have almost no blowby.

[480sx]

The breather your speaking of is actually a slight vacuum on the valve cover from the intake pipe.

The fresh air is not going to magically circulate through your engine, its going to go from your valve cover breather, down your front timing cover, and out the pcv valve.

Im not saying that your method doesnt work, im just saying its not ideal.