supergreenNA1

just built a b18c for turbo. i have started it up 4 times and everything seems ok. right before the second time i started the engine i installed an oil catch can with it filtered to the atmosphere. the first time after the catch can install seemed ok... but 2nite i fired her up again and noticed a small but steady amount of smoke coming out of the filter on the catch can. anyone else experience this with a catch can on a built engine? is the smoke normal?


[Modified by supergreenSol, 10:03 PM 8/7/2002]

Madness

could it be moisture (water) evaporating istead of oil?
i've seen that before -- kinda looks like smoke HTH

supergreenNA1

so.... some of the people on this board have built engines... right?

X2BOARD

Yes, some of us do...

Yes, a small amount of faint smoke emerging from the catch can filter is normal. It's just doing it's job extracting excessive crankcase vapors from your system. You shouldn't have anything to worry about.

BTW, how did you have your 'intake' for the can setup ? Which catch can are you running ?

X2

supergreenNA1

it's just a hose coming from the black can in back of the block running to a greddy catch can. i put a small k&n filter on the nipple that would normally run back into the intake manifold.

X2BOARD

Ok, sounds about right.

b20civic

also, you might find that after the motor is broken in, and the rings have seated that the smoke stops coming out of the filter. I would imagine a little is okay, but id bet its because your rings havent seated yet, if the motor was freshly rebuilt.

Ash J. Williams

the smoke/mist os normal on atmo vented catch cans. you also will notice a strong motor oil/gas smell as you pop the hood, as in carbed motors. that is also normal. prepare to wipe oily film off your accesories, BTW.
why don't you vent the catch can back into the intake?
stan

supergreenNA1

the catch can isn't run back into the intake because i'm trying to keep that crap out of the system..... hence the catch can.

X2BOARD

Yeah, the presence of the catch can vapors in the intake charge increase chances of detonation.

X2

downpipe

supergreensol, did you include your pcv valve in this setup? if so, how does it open? i was reading that the pcv valve only opens when it sees vacuum.

supergreenNA1

no. no pcv valve. just a hose from the black can in back of the block directly to the greddy can.

CalvitoSol

sorry to bring up this old post but, if you just put a breather on the can w/o hooking it back up to the IM, what happens to the whole that's left on the manifold? do you just plug it up? also, i've heard that pcv valves are useless when boosting. why is that? what are they for? if you don't need it, why is it there in the first place? sorry for all the questions but i'm still in the learning process.

Bnjmn

PCV valves are only open under vacuum, so they close during boost. They are still useful in a boosted car because some ventilation of the crankcase is better than none (you are never always boosting). If the catchcan isn't hooked up to the intake manifold, how do the oil vapors get sucked through the catchcan so it can do its job? The whole idea of the catchcan is the there is a PCV valve, that opens under vacuum, that vacuum sucks the oil vapors from the crankcase to the IM, but on the way to the IM those vapors go through a catchcan (ideally internally baffled) where they turn back into liquid oil. That way you should have very little oil going back to the intake manifold. The only way it should differ from the stock system is that there is a catchcan between the intake and the PCV valve. Otherwise all you are doing is creating an elaborate filter breather setup, which isn't too ideal on an engine that is designed for a PCV system.

ben

madman604

heres what i found.

if you plug up the valve cover vent with say a catch can or valve. it forces oil into the cylinders causing mondo smoke. if you attach a catchcan, make sure the gasses can actually flow thru the can (hook up to the intake) if you only hook up one end, you'll get smoke.

so hook it up to the intake. not much oil will make it thru anyways. VS just a hose from the cover to the intake.

X2BOARD

Well, the PCV system is designed (on our cars) for an N/A setup with a particular crankcase pressure to deal with... relatively low levels. It vents the vapor back to the I/M, where it is burned with the next combustion cycle.

The reason we should remove the PCV system in favor of an open loop breather/catch can set up is...

1) The PCV system was not designed to deal with the increase crankcase pressure of a turbo motor, thus the stock PCV valve will get stuck trying to deal with the pressure....doink... broken.
2) Turbos are not stock on most cars, therefore, the motor will not operate properly w/ the PCV system as it is designed for stock configuration.
3) The PCV system is designed to vent oil vapors back into the combustion process, this does 2 things: a) It makes the motor run dirty, as it has to burn oil with the mixture b) Oil vapors that exit the crankcase are hot and heat doesn't mix well with forced induction and the fact that oil vapors induce detonation doesn't support the use of a closed loop PCV doesn't help it's function either. Detonation in an FI engine will easily mean 're-build'.

But I will agree, that on a stock or lightly modded (I/H/E) car... the PCV system should be kept in place, with no breathers... as taking it off on this type of setup would impede preformance.

X2

madman604

forgot 1 thing. Isn't the PCV system supposed to create a partial vaccuum in the crankcase/oilpan to let the crank and rods spin more freely = more power?

Bnjmn

So you are saying that in a boosted car that there is no need for the intake manifold to provide a vacuum to suck vapors out of the crankcase? They just leave on their own?
Also, with a catchcan + PCV valve, you should have next to no oil on your intake and no detonation problems as well.
About the PCV valve breaking, that could definately be a problem- how common is this?

Ben

X2BOARD

You shouldn't run a PCV valve with a catch can, it's pointless.

If you read my posts carefully, you will see that I did not recommend running the valve at all.

And the oil DOES make it to the intake while the PCV system is in place... that's what it's there for. With an open loop system (catch can), the vapors leave on their own.

X2

Bnjmn

I don't think I'm making myself clear here- No doubt oil will get into the intake with just a PCV valve in place, just look at any stock manifold. BUT you should have next to no oil in the intake with a closed loop system and a catchcan in place, whether you are using a PCV or not.
My argument is that a closed loop (using the intake manifold as the vacuum source) will be much more effective than just having an open loop that vents to the atmostphere. Why not just run a little filter on the valvecover if you are going to do that?

Ben

Ri5e

If you have the catch can connected to the Block and then vent out into the air, that would make the catch can worthless.

The purpose of a catch can is to clean the oily air from the crank case and retain the pcv so that vacuum from the intake manifold is used to "help" suck out the crank case air/pressure (so you don't blow oil seals) and recycle it into the manifold.

Under boost the catch can is worthless because the pcv valve closes. All the pressure in the crank case exits via the valve cover breather nipple.

But say your boosting 13 psi and shift, the manifold goes back to vacuum and quickly "sucks" in a lot of oily crap from the crank case and then your back into positive manifold pressure. So the Catch can IS doing its job in between boost shifts.


[Modified by CRV Monster, 8:35 PM 9/11/2002]

madman604

don't most catchcans have some sort of filtering media to trap oil vapour until it collects into droplets. then you empty out the can when its full of liquid oil. understandably some oil makes it through, but not enough to cause detonation IMO

CalvitoSol

so, would it be ideal to have 2 catchcans? i know it sounds overboard but if the manifold "sucks" out pressure from the crankcase while shifting because of vaccum and the valve cover venting while under boost, shouldn't there be something in between BOTH the pcv/stock oilbox and the valve cover before it reaches the IM? also, if you remove the pcv on a fi car, wouldn't the engine itself lose pressure all the time? is this bad or is crankcase pressure not needed on fi cars? also, what the deal w/ the vent nipple that runs from the valve cover to the im? does it vent or suck in air? i wanted to put a breather there to get rid of unnecessary things from the engine but alot of people suggested that it needed a certain amount of pressure on newer engines. (i have a 94 sol b16a3). on a side note: i've been piecing my kit together for the past 4 months now and i'm done w/ all the basics from the intecooler and down to the dsm injectors but still short on cash for a 2b, tuning and a few other misc. hardware. everytime i try saving up, i come across a thread discussing ways to make your car safer. like the catch can, hondata 2b after i originally decided to go w/ the vafc hack, etc. i really want to have the turbo on my car already but kinda sketchy on whether or not my car will be setup properly. i don't really wanna cut corners, so are catchcans really necessary? how are stock engines affected w/o catchcans? will boosting a stock n/a motor affect it that much where a catchcan is really necessary? i guess if a stock car can benefit from a catchcan, a fi would definetely need one too....right?

earl

I don't think I can buy your theory. The first goal is to relieve positive pressure in the oil pan not to suck "oily crap" from the pan. It's an OIL PAN so you want oil in it. The positive pressure pushes oil vapors past the rings which is bad. If the block is vented to the can, then positive pressure will bleed off thru the can.
The ideal situation would be to put negative pressure (vacuum) in the pan to help the rings seal. This can be done with a vacuum pump in a race car or manifold vacuum thru the pvc. But to do this is to put oil into the intake charge which promotes detonation.

TurboDANDEE

Well im confused now. So what is the CORRECT way to hook up a catch can for a turbo motor so we can end all this??


[Modified by JiSATSU RaceR, 8:06 AM 9/12/2002]