Catch can Causing smoke

[bewstin]

So, today i installed my oil catch can, started up the car, and within seconds tons of smoke was comming off the exhaust manifold, and filling up the car with oil smoke while it was just idling!! I thought the catch can was supposed to reduce crankcase pressure!! I attached a pic of how i had it setup. Also when the car was running i pulled off the hose going to the breather on the left side of the valve cover, and i could feel a little pressure puffing out of it. Is this normal at idle??

 

[dfwdsmer]

Well you have it set up wrong take the hose off the pcv valve and connect it to your intake

 

[JusMX141]

You can't run both freakin' lines to a sealed catch can....how is it going to vent?

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Right now you have ZERO crankcase ventilation. You'll be lucky if your turbo isn't destroyed from all the oil bypassing the sealing rings. This is a perfect example of how these cars get such a bad reputation for being unreliable.

 

[bewstin]

I ended up unhooking it so its back to the stock setup right now. I thought you could delete the PCV and run a straight fitting and cap the intake manifold?? If not should i just have the one breather from the valve cover going to the catch can, and then just put a breather filter on the other fitting on the catch can?? That was gunna be my next attempt.

Thats what i thought when I was doing it, because the PCV vents excess crank case pressure back into the intake manifold. I have a friend who lives by these cars and hes the one that told me to do it this way. I took his word seeing as he has a 700HP 89 mirage, automatic 1g drag car, and an EVOVIII. I must not of listened well enough. Funny i can rebuild my engine but cant install a catch can, haha. I feel like an idiot right now sorry everyone. So what would be the proper installation seeing as there are two fitting on my catch can...

You can't run both freakin' lines to a sealed catch can....how is it going to vent?

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Right now you have ZERO crankcase ventilation. You'll be lucky if your turbo isn't destroyed from all the oil bypassing the sealing rings. This is a perfect example of how these cars get such a bad reputation for being unreliable.

For what its worth the car only idled for about 25 seconds before i shut it off. Never rev'd, or even moved.

 

[JusMX141]

So what would be the proper installation seeing as there are two fitting on my catch can...

Throw away that eBay P.O.S. and buy a setup that will actually do something.

Start by reading this.

http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

 

[bewstin]

I actually have a Greddy catch can as well but couldn't find small enough barb fittings in metric to match up to the size of my valve cover breather, thats why I bought that one. No need to get hostile man, I'm asking for help not to be talked down to, thank you.

Thank you for the link, that cleared everything up as well. Ill re-install everything properly tomorrow. =)

And sorry if i misread your suggestion, i just get frustrated when i don't think and make dumb mistakes.

 

[JusMX141]

And sorry if i misread your suggestion, i just get frustrated when i don't think and make dumb mistakes.

Sorry if you mistook my hostility; I just get frustrated when eBay parts ruin perfectly good cars.

 

[bewstin]

Oh i totally understand you there. I'm one for doing things right, i don't like hacking anything or taking shortcuts. Which is why this kinda upset me so much. Ill have to go hardware store hopping tomorrow and get some barb fittings in 5/16 size, the ones on the greddy catch can now are like 9/16 (HUGE). Thanks for the help, really cleared things up.

 

[Calan]

Oh i totally understand you there. I'm one for doing things right, i don't like hacking anything or taking shortcuts. Which is why this kinda upset me so much. Ill have to go hardware store hopping tomorrow and get some barb fittings in 5/16 size, the ones on the greddy catch can now are like 9/16 (HUGE). Thanks for the help, really cleared things up.

A single 5/16" line is way too small for anything but a stock car. And even then, it wouldn't hurt to go bigger.

You really need something like two -6AN lines going from the VC to a sealed catch can that is fed back to the turbo inlet, or at least two -10AN lines (or maybe larger in some cases) if you are running to a can that is open to atmosphere...which coincidentally is why those cheap empty cans come with larger fittings.

Regardless of the line size, you will never be below atmospheric pressure in the crankcase unless you run a sealed can with suction being applied to the other side of it.

BTW - You might want to lose that Unorthodox crank pulley and go back to a factory dampener.

 

[bewstin]

BTW - You might want to lose that Unorthodox crank pulley and go back to a factory dampener.

I'll gladly take dsm advice when given. Whats the reason??? Getting rid of vibration.. or something more serious.

 

[Calan]

There has been tons of discussion on it (just do a little searching), but there is one heated thread that covers it pretty well. I'd start with Unorthodox Racing Lightened Pulleys - Squeeling When Cold... (post #52), where tKelly27 posted some good info and links to some of the theory behind it.

 

[bewstin]

Thanks a bunch for the heads up

 

[Calan]

NP

As you probably noticed, it's one of those topics that generates some controversy.

 

[bewstin]

Yea, all i all, they couldn't of said it better. For the little HP you get from it, its not worth damaging the engine. I'm glad i kept my stock crank pulley, i will throw that on tonight when i fix my Oil catch can setup.

 

[Calan]

One more word of advice... never use a dampener (crank pulley) from an auto parts store; always go with direct OEM from a dealer, or one of the Fluidampr or ATI units. There have been several reports of brand new parts store dampeners coming apart after only a few thousand miles, and it happened to me as well with one purchased from O'Reilly's.

Before you bolt your old stocker back up, make sure the rubber isn't brittle and chipping away...especially if it's been sitting for a while. When those things separate at high RPM, it isn't pleasant.

 

[Tyeler18]

Craig, what is your input on the size for the vacuum source? My catch can is 2 -6an fittings and one (unknown) size vacuum fitting. I just got to thinking, and I'm pretty sure my barb fitting for my vacuum source is smaller than -6an. I have both valve cover fittings run to the -6an and then the vacuum source run to the intake pipe. I'll have to go out and look, but I'm pretty positive the barb fitting is smaller than the other two. Think this will cause a problem? Especially since I'm running both lines to the same can, should I get something that's a 1/2 fitting instead?

 

[Calan]

Craig, what is your input on the size for the vacuum source?

It varies a lot from setup to setup, but for a can with very little to no pressure drop (like an empty can or one with just some coarse mesh in it), I would run a line with the same cross sectional area as the total of what is leaving the VC.

A -6AN line usually has an ID of roughly 5/16", or .313" (worst case, accounting for the true ID of most fittings). The cross-sectional area of that line would be around .077" (Pi * r * r), so that means that you have about .154" worth of area in the lines for air to leave the VC with two lines (.077 * 2). So, you would need a single line with .154" of cross-sectional area to provide the same amount of airflow as those two -6AN lines. Working backwards, that gives us an ID of roughly .443".

SQRT(.154 / pi) * 2 = .443"

That ID is midway between a an -8AN line and a -10AN line; either one would probably work.

If you are running a can with a filter in it (and therefore a pressure drop), I would go one size larger on the line going to the turbo to compensate for the drop across the filter, unless the lines coming off the VC are over-sized to begin with. In that case, you may be able to run the same size line on the outlet as you are on the inlets. For example, I build quite a few setups that use -10AN lines all the way around. On my own car with one of my VS3 cans, I currently run -8AN lines from the VC with a -10AN line to the turbo, and it seems to work fine. As always, YMMV.

With all that said:

1). The line ID's mentioned are always nominal. True hose and fitting sizes vary by manufacturer, so use that ^ as a rough guide.

2). The smallest restriction in the airflow path determines the cross-sectional area. Having a 1/2" ID line doesn't mean much if it necks down to 5/16" at the VC nipple.

3). Elbows, line length, and even the type of hose can affect flow... so keep that in mind when deciding what size and type of lines to run.

4). All of this only applies to a sealed can with a suction source applied opposite the inlets. If the can is open with a breather on top, run the largest lines possible off the VC (within reason of course.