OK before I ask my question let me explain what I'm talking about. On the back of my b18a block there is a black "breather box". It has two holes on the top. One is connected to a little tube that comes out of the block just above the box, and the other hole has a tube that goes up and connects to the intake manifold plenum. Here's a little diagram I drew:


I am currently running a vent system using two -10 fitting welded to the valvecover, connected to a venter catch can (Jaz w/breather). Here's a pic:


A lot of people say that when using the vent system like I have, you should plug the breather box on the block. Usually they take the breather box off and use a rubber filler plug (I believe Z10 sells them).

Now my question is, wouldn't it work just as well to just plug the two outlets from the box, and plug that little tube coming out of the block? What I'm saying is to plug all the tubes that I have circled in red in the pics below:



Wouldn't this have the same effect as removing the box entirely and plugging the hole where it is attached? I was planning to plug all these tubes with the little rubber caps you can buy at pep boys, attached with a little adhesive to make sure they don't blow off.

Also the tube that comes out of the block in (on the left in the third pic) is actually a fitting threaded into the block - can I just take this off and screw a bolt in there? Is it a typical metric thread or some kind of pipe thread?

And finally, regarding the stock breather that goes from the nipple on the rear of the valve cover (just behind the oil filler cap) to the intake pipe - some people have said that I should plug this one too, and just let my vent system at the front do all the venting. What is everyone's opinion on this? I'd rather not leave it connected to my intake pipe as I would prefer not to have oil vapors contaminating my intake charge. Should I just cap it off, or would it be better to put one of those little breather filters on it, or should I leave it connected to the intake pipe?

Thanks in advance for any help...

 

Come on guys please help with this...

 

i would like to know also

 

bump for answers/advice...

 

use a freeze plug to plug the hole when removing the black box, and a 1/8" pipe plug for the fitting on the head parts shouldnt be but a few $ and pretty simple to install

 

For the tube on the valve cover, just put a breather filter on it. For the PVC pipe connection,(black box your talking about) just let it air into the atmosphere. Plug the intake side with a bolt(12mm), the one comming from your intake manifold.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B20TDC2 &raquo;</TD></TR><TR><TD CLASS="quote">use a freeze plug to plug the hole when removing the black box, and a 1/8" pipe plug for the fitting on the head parts shouldnt be but a few $ and pretty simple to install</TD></TR></TABLE>

can you get these at the hardware store?

what size freeze plug do you need?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16a@9krpm &raquo;</TD></TR><TR><TD CLASS="quote">For the tube on the valve cover, just put a breather filter on it. For the PVC pipe connection,(black box your talking about) just let it air into the atmosphere. Plug the intake side with a bolt(12mm), the one comming from your intake manifold.</TD></TR></TABLE>

tried that and I could smell the oil vapors inside my car

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowegxxrevolt &raquo;</TD></TR><TR><TD CLASS="quote">

can you get these at the hardware store?

what size freeze plug do you need?</TD></TR></TABLE>

looks to be about an 1&1/4" (freeze plug) the one i have in front of me is a dorman part#565-104 heres a pic if it helps click to enlarge



the little plug is the one that goesin the head

 

Just out of curiosity, why do you want to plug it up, crankcase pressure would build in the bottom end. I'm running the same valve cover breather as you have (I have a Moroso can), but I also have the rear stock breather box. What I did on the rear though, is instead of having it run to the PCV valve then to the intake manifold, I have a 1/4"NPT to 6AN fitting in place of the plastic nipple and braided line that runes to a Mororo catch can with a breather element on top. I don't like the idea of closing of the crankcase. Here's a shot of it, I just ran that to a Moroso can with a beather on top.




Modified by PandaHatch at 4:57 AM 3/23/2005

 

:subscribes:

Can you show a pic of where your front 2 hosed run to?

I straight up looped the breather box into itself and ran the gold nipple to a pcv then to my IM. Pretty much bypassed the breather box. I gotta change that one of these days.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PandaHatch &raquo;</TD></TR><TR><TD CLASS="quote">Just out of curiosity, why do you want to plug it up, crankcase pressure would build in the bottom end. I'm running the same valve cover breather as you have (I have a Moroso can), but I also have the rear stock breather box. What I did on the rear though, is instead of having it run to the PCV valve then to the intake manifold, I have a 1/4"NPT to 6AN fitting in place of the plastic nipple and braided line that runes to a Mororo catch can with a breather element on top. I don't like the idea of closing of the crankcase. Here's a shot of it, I just ran that to a Moroso can with a beather on top.




Modified by PandaHatch at 4:57 AM 3/23/2005</TD></TR></TABLE>

what you are running is sort of the same principle as the endyn kit with it you remove the breather box which doesnt come on the newer honda blocks . on the endyn kit you remove the plugs on each side of the oil filter. then install thier fittings and loop the modified moroso can into it to relieve pressure

 

I had th e Endyn kit on my B20VTEC, after I switech to a Dart block, the fitting for the back doesn't fit due to the Dart having 3/4"NPT plugs. I just used the Endyn tank for my valve cover breather.

 

ok i see what happened to your b20/vtec if you dont mind me asking

 

Valve seat cracked into 3 pieces, bent the valve and went through the piston, only had 300 miles on it after being built. Destroyed everything besides rods, cams and springs/retainers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PandaHatch &raquo;</TD></TR><TR><TD CLASS="quote">Just out of curiosity, why do you want to plug it up, crankcase pressure would build in the bottom end. I'm running the same valve cover breather as you have (I have a Moroso can), but I also have the rear stock breather box. What I did on the rear though, is instead of having it run to the PCV valve then to the intake manifold, I have a 1/4"NPT to 6AN fitting in place of the plastic nipple and braided line that runes to a Mororo catch can with a breather element on top. I don't like the idea of closing of the crankcase. Here's a shot of it, I just ran that to a Moroso can with a beather on top.</TD></TR></TABLE>

I was told by a few people that the valve cover breather provide enough venting for the block and their was no need to run the rear breather box. Maybe I'm wrong?

 

Let's put it this way, the rear box isn't going to hurt anything if you leave it on, if you take it off, it will just build up pressure in the bottom end. This is why when people do B20VTECs and 96+ LSVTECs, they usually run an Endyn breather kit since they don't have a factory breather box to release the pressure. I say leave it how it is, or run it to a vented catch can.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PandaHatch &raquo;</TD></TR><TR><TD CLASS="quote">Let's put it this way, the rear box isn't going to hurt anything if you leave it on, if you take it off, it will just build up pressure in the bottom end. This is why when people do B20VTECs and 96+ LSVTECs, they usually run an Endyn breather kit since they don't have a factory breather box to release the pressure. I say leave it how it is, or run it to a vented catch can. </TD></TR></TABLE>

ok I guess that makes sense. So I know that I should run the line that usually goes from breather box -&gt; intake manifold into the catch can, what about the line that comes off the fitting on the back of the block/head?

 

Leave the fitting that comes off the block conencted to the breather box. The other nipple, runa line off that to the catch can and then from the catch can back to the intake manifold, all you're doing, is running it inline.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PandaHatch &raquo;</TD></TR><TR><TD CLASS="quote">Leave the fitting that comes off the block conencted to the breather box. The other nipple, runa line off that to the catch can and then from the catch can back to the intake manifold, all you're doing, is running it inline. </TD></TR></TABLE>

Why does it need to be inline? It needs vacuum from the intake manifold for some reason? It seems like I could just run it to the catch can and that's it - if the breather box is basically just a baffled "hole in the block" won't the crankcase pressure escape on its own through the hole?

I know the vacuum from the intake might reduce the pressure a little more, but then again it might suck oil or oil vapors into the incoming air as well...

Wait I just realized that since I am running a vented catch can then connecting it to the intake manifold will not pull air from the breather box it will just pull air in through the breather at the top of the catch can (path of least resistance). So that would be pointless...