Oil Catch Can/Separator

[1993MTXSHO]

Hey guys been a while since I posted, life's been crazy the past few years but I'm finally looking at putting a catch can on my 93 mtx and I've been doing all sorts of reading and I'm still confused. I see some guys putting breathers on and some guys saying you have to keep it all connected so the MAF reads all incoming air.

I read this thread a bunch of times but still don't fully grasp this.

http://www.shoforum.com/index.php?threads/crankcase-pressure.116823/#post-1277952

Read this whole mess too:

http://www.explorerforum.com/forums/showthread.php?t=148135&highlight=oil+separator


I think what I'm reading my be boosted vs. NA setups? My car is NA but I want to keep all or at least most of the junk out of my intake. I've read that keeping it all connected helps pull all the gasses out of the crank case better vs just venting it. Also saw that I really may need 2 cat cans to catch everything.

Can someone clear this up for me? I can't seem to wrap my head around it.

TIA

 

[Irish Pride]

What I did was eliminate the hose coming off the valve cover and added a catch can between the hose coming out of the valley and to the throttle body. You can see all I did is added a breather filter to the valve cover and capped the port on the intake. For the can I used new rubber line coming from the valley and I found a preformed hose with a 180° bend in it to go from the can up to the TB. Works great with no issues and the amount of sludge it catches is amazing.

image by Chad Corcoran, on Flickr

 

[1993MTXSHO]

Won't that cause unmetered air to enter the engine and throw off the computer?

 

[Irish Pride]

Won't that cause unmetered air to enter the engine and throw off the computer?

The air in the PCV system is coming from the crank case. As long as you cap the port on the intake no unmetered air is going into the engine. The line running to the catch can already runs to the TB. All you are doing is adding a can to it.

 

[1993MTXSHO]

I'm trying to get a grasp on this so forgive me if I'm ignorant, but if the PCV in the center of the block runs into the intake, and there's a breather on the valve cover, that's all pulling from the crankcase. If the valve cover is vented isn't that able to pull in unmetered air right through the head/and through the crankcase?

 

[Irish Pride]

image by Chad Corcoran, on Flickr

 

[shomethe$$$]

No the engine will not get un-metered air back into the engine because that air doesn't have a path back to the throttle body or intake. Block all the ports on the TB and intake.

If you have a closed system catch can (one which actually separates oil and air, with baffles, foams etc.), you could plumb the valve cover and valley hose to the catch can, then you can plumb the catch can outlet back into the intake with a check valve (if you have boost). If you vent the valve cover and try to plumb the catch can back into the intake then you will get un-metered air back in. I think this is where the confusion is.

But with this system you may eliminate that nasty odor when you have the windows open but no matter how good the catch can separates air and oil, some oil will get back in if you plumb it back to the intake. I prefer vent to atmosphere and block everything else off.

 

[quikSHOilver]

What I did... I fabricated this simple oil/air separator using 2.5"x 4" steel pipe and 3/16"x 3" plates to put inside act as divider then stuffed the bottom with steel wool. Used 3/8" barb for hose attachment and not to mention small air filter breather on top opposite the barbs. Finally, I drilled and use 3/8" shut off valve in 0f bottom (opposite side from top where air breather reside) to drain crud out.




Drilled "3/8 for barbs


Divider plate welded in


Drilled the top cover for air breather as well bottom for drain. Fabbed up a bracket.


Powdercoated. I run hose from middle of valley to lower barb, upper barb goes to under intake by throttle body.

That doing so has reduce crud in the intake system significantly.

 

[rubydist]

where we are, with emissions testing, we cannot have those little filters like Chad shows on the front valve cover. so, the catchcan part of what he did is fine, you just need to keep that other hose from the front valve cover to the intake in place, so that there is not the possibility of "pollution" coming out of the front valve cover.

 

[1993MTXSHO]

So most of the oil spray comes from the center of the block, not the valve cover?

 

[shomethe$$$]

So most of the oil spray comes from the center of the block, not the valve cover?

Yes, my rarely had oil soaked onto the front filter, if you boost more often the front filter would get dirty a lot quicker. The valley one got dirty pretty quick. For a heavily boosted car a rear vent would be good but you would either have to take the internal baffles from the front valve cover, if you have an extra, or make a baffle.

 

[shomethe$$$]

where we are, with emissions testing, we cannot have those little filters like Chad shows on the front valve cover. so, the catchcan part of what he did is fine, you just need to keep that other hose from the front valve cover to the intake in place, so that there is not the possibility of "pollution" coming out of the front valve cover.

You can't keep that in place if your valley one is going to open air or the catch can unless you put a check valve on it (valley or valve cover) which don't work anyway in boost. Its best just to block it off and route the other two to the catch can. I guess you can make a pretend hose and then tee it off to the catch can.

I wouldn't advise anyone with a street car to use a vent filter, the smell is bad.

 

[1993MTXSHO]

My car is just a heavily modded NA 3.3. no boost or nitrous at the moment. Maybe in the future, but for now what do you think the best setup is for me?

 

[shomethe$$$]

My car is just a heavily modded NA 3.3. no boost or nitrous at the moment. Maybe in the future, but for now what do you think the best setup is for me?

Just route both to air or to a vented catch can, then block the intake and TB. Before emissions, connect them back.

 

[SHO~OFF]

I have a 91 sho. What is this catch can and is it something I should look into?