catch can setup?

[wde_bdy]

the problem with keeping the pcv valve is you still have fumes getting into the intake.

I may be wrong but I presumed the PCV valve is mounted into the rocker cover, so what I mean when I say keep the PCV valve is leave it in the line to the catch can so that fumes etc can only flow out of the rocker cover.

Callum

[Dirtbag]

Cheers for the discussion guys, Think I might go ahead with option 2 once I get hold of a can and breather. Is it alright to run a pipe to the breather somewhere closer to air flow, so that the fumes do not sit around under the bonnet?

[Mr Revhead]

yes its in the top in the pic above. its the grey plastic angle piece.

ok i got ya. what i was meaning is with that other line from the can to the intake, youll still get fumes that way

[TWSTD]

So I would be drilling a whole and mounting a nozzle for a pipe to fit over on the side of the plenum?

Sorry - i was referencing the plumbing on my 3sgte when i edited your pic. In my case the PCV valve breather line runs straight into the intake manifold. I was not suggesting you tap a port into the intake mani!

On the 3s at any rate, a sealed catch can in place as per my drawing prevents the oil that leaves the PCV valve getting into the intake mani. I have tested this in my application both before and after catch can install (using a small clear fuel filter as shown here: http://i5.tinypic.com/20j64py.jpg). Prior to catch can install it filled with oil within 4 weeks. After catch can install no sign of oil after 8 weeks.

Also the filter on the rocker cover is simply going to allow you to suck air into the intake via the PCV valve and catch can, effectively a vacuum leak.

No it wont - there is not a vacume inside the cyl head, only positive pressure. Put your hand over that rocker cover breather with the engine running - you will feel it "blowing" the blow-by out.

PCV valve lets air be sucked out of the rocker cover and should be left in with catch can setups.

I was not suggesting you remove the PCV valve - quite to the contrary, it is important to keep that in place!

[Mr Revhead]

the pcv is a one way valve.
with that filter there air will come in the filter, and out the pvc, hence the leak as that air will enter the inlet after the a/f meter.
how ever a MAP car may be ok

[Steelo]

Hey,

This looks like a pretty cheap and effective mod that I can do to my Bz-r.

Is the option 2 (2nd pic) with the breather the best way to go? in terms of results etc...?

Can you guys recomend some products to me?

Can someone post up a pic of their set up?

Steelo

[Jebus]

I have a hose that goes from my rocker to the ground, captain planet loves it. Like this because I have a FWD Throttle body on an AE86 manifold.

[Dirtbag]

captain planet loves it.

just combine your powers and you'll be fine

Wheres a good place to get some hoses for it all? You don't need anything special for them do you? Just hoses that fit and some hose clamps?

[4000GT]

my catch cans a coke bottle

haha I use a 1l antifreeze container.

All that stuff is fine unless you are racing... they are pretty strict on can capacity etc.

1l antifreeze container is fine. 1l for a sub 2000cc engine (as explained by Callum), been through many a scrutineering with that sucker.

Maybe for drag racing, not circuit racing at CCC events etc.

[Caveman]

the pcv is a one way valve.
with that filter there air will come in the filter, and out the pvc, hence the leak as that air will enter the inlet after the a/f meter.
how ever a MAP car may be ok

what the hell, a pvc is not just a one way valve, if you actually knew how it worked you wouldnt be saying that.

It is a positive crank ventilation valve.

When at idle the pvc valve is mostly closed. This will not negatively affect idle speed and not cause a 'vacum leak'. Where do you think the other pipe is attached to anyway?

At WOT the valve opens as manifold pressure is low hence the spring allowing the pcv valve to open and vent gas through from the crank case into the manifold.

It is a one way valve in that if the manifold becomes pressurised the valve will close, that doesnt matter on NA cars so dont worry about it.

Best way to do it is the way described in TWSTDs picture.

[matt dunn]

what the hell, a pvc is not just a one way valve, if you actually knew how it worked you wouldnt be saying that.

It is a positive crank ventilation valve.

Agreed.

The PCV valve is more of a vacuum regulating valve.
Vacuum from the manifold suck mit closed against spring pressure.

At idle there is high manifold vacuum and the valve is there to stop the full vacuum getting into the sump.
Vacuum in there is as bad as pressure.
Pressure can blow out the rear main seal etc etc,
Too much vacuum in the sump will suck them in an d cause them to leak just as much.

The reason to fit a catch can is to stop the oil vapours entering the intake as they lower the octane rating of your air fuel mix and cause detonation which the ecu senses and retards the timing and you loose power.

If you Are going to fit a catch can and still plumb part of it back,
what is the point?

You may stop mthe actual oil liquid from getting there,
but you will not stop the vapours/fumes/smell from getting in there.

Matt

[Dirtbag]

The reason to fit a catch can is to stop the oil vapours entering the intake as they lower the octane rating of your air fuel mix and cause detonation which the ecu senses and retards the timing and you loose power.
Matt

So best idea is to have it all finishing up in the catch can with a filter? or without a filter?

[4000GT]

The reason to fit a catch can is to stop the oil vapours entering the intake as they lower the octane rating of your air fuel mix and cause detonation which the ecu senses and retards the timing and you loose power.
Matt

So best idea is to have it all finishing up in the catch can with a filter? or without a filter?

You have to run a filter, the point is to relieve crank case pressure... if you dont have a vent you might as well just block the holes and not even have a can.

[Loudtoy]

Go with option 2 in your pics, mount the can where the igniter is and you won't get any smell. I had it this way on my old 20v 101 and never got any smell and i used to empty it about every month and a half or so used to be pretty full by then but it wasn't a very big can really only bout 500mills

[Jebus]

The reason to fit a catch can is to stop the oil vapours entering the intake as they lower the octane rating of your air fuel mix and cause detonation which the ecu senses and retards the timing and you loose power.
Matt

So best idea is to have it all finishing up in the catch can with a filter? or without a filter?

You have to run a filter, the point is to relieve crank case pressure... if you dont have a vent you might as well just block the holes and not even have a can.

Block both holes and tell me how long your rear main stays in your motor for.

[Caveman]

The reason to fit a catch can is to stop the oil vapours entering the intake as they lower the octane rating of your air fuel mix and cause detonation which the ecu senses and retards the timing and you loose power.
Matt

So best idea is to have it all finishing up in the catch can with a filter? or without a filter?

You have to run a filter, the point is to relieve crank case pressure... if you dont have a vent you might as well just block the holes and not even have a can.

Block both holes and tell me how long your rear main stays in your motor for.

I think he was being sarcastic
The reason i suggest venting back to the manifold on a street car is the fumes are terrible. Race is a different story however

If you dont want to plumb it back run a long hose to the wheel well to vent, that way little of the fumes will get in the cabin

[Mr Revhead]

so i took a few words to explain what u took 3 paragraphs


the fumes arnt that bad, you catch a whiff every now and then, thats about it

[Dirtbag]

Completely forgot to ask, do i need to block up this hole?:

[Mr Revhead]

YES

[Dirtbag]

CHEERS