Just recently I switched from having my pcv line running from the black box in the back of my block going to the intake manifold to just having the line dumped to the ground with the check valve removed. I did this in hopes that it would vent much better in boost, but ever since I did that(just about a week ago) it seems to have recieved an increased amount of noticable blowby from the valvecover. I had a straight line running from the valvcover and dumping to the ground too, but i removed it because I saw a good bit of oilage dripping from the end of it under the car. I tried revving the motor up at idle and noticed a very small puff of vapor come out of the valvecover at around 5k rpms that I didn't really notice before i performed that pcv mod. Is it bad not to have any vacuum running to the crankcase at all at idle? I thought letting it vent in boost at least would be a better advantage.

BTW my car doesn't smoke AT ALL out of the tailpipe in boost like its burning oil and compression is... 185 180 185 190 straight across. This is a y8 block with over 100k miles on it. I have been running 12psi daily for a while now.

 

yea i noticed the same thing when i took my pcv out to let it vent...it started spitting oil out valve cover...changed it back to stock and it stopped doing it...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jockobo &raquo;</TD></TR><TR><TD CLASS="quote">yea i noticed the same thing when i took my pcv out to let it vent...it started spitting oil out valve cover...changed it back to stock and it stopped doing it...</TD></TR></TABLE>
damn that makes me feel so much better. Thanx man . Is it really worse running the motor with the PCV though? I'll take the increased junk out the valvecover if I can get better venting in boost.

 

it didnt stop spitting oil out the valve cover when you install the line back, it is just spitting into the intake manifold. if you take the line off the valve cover and you have oil spitting out then you have major blow by. and you might want to think about doing a compression check.


Modified by b20turbojason at 6:02 PM 2/14/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b20turbojason &raquo;</TD></TR><TR><TD CLASS="quote">it didnt stop spitting oil out the valve cover when you install the line back, it is just spitting into the intake manifold. if you take the line off the valve cover and you have oil spitting out then you have major blow by. and you might want to think about doing a compression check.


Modified by b20turbojason at 6:02 PM 2/14/2006</TD></TR></TABLE>
Check out my post. I did to a compression check. 185 180 185 190...compression is the same everytime I check it. Also the oil doesn't spit all over the engine bay or anything..just a nice dribble down the back of the valvecover. Also remember it is still vented to come out of the back of the block too so there is just no vacuum on it like there was before.

 

I have come to the conclusion it is because of the small diameter lines you used.

This small diameter makes the velocity so high inside the lines that it is actually sucking up extra oil unnecessarily.

I have -12 lines on the back of the block AND valvecover and it does not fill up or spew as much as when I used smaller lines.

EDIT:
I had a setup similar to yours and had it dump to the ground directly. One the dyno, I watched MORE than a quart of oil spew out by the end of the dyno session.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike1114 &raquo;</TD></TR><TR><TD CLASS="quote">I have come to the conclusion it is because of the small diameter lines you used.

This small diameter makes the velocity so high inside the lines that it is actually sucking up extra oil unnecessarily.

I have -12 lines on the back of the block AND valvecover and it does not fill up or spew as much as when I used smaller lines.

EDIT:
I had a setup similar to yours and had it dump to the ground directly. One the dyno, I watched MORE than a quart of oil spew out by the end of the dyno session.</TD></TR></TABLE>
damn thats a lot of oil . Have you come to the conclusion that everything is fine with your setup? As in good compression and everything? The line i'm using on the back of the block is the stock pcv line. Maybe i should just take the line off altogether and just let it dump out the pcv box itself. Also the line i'm running on the valvecover is rather large. 1/2-3/4 inch I believe.

 

If you take the line off the black box, you will get oil EVERYWHERE. IT really spits it when your WOT!!

My motor did this from day one of startup of freshly new build.

 

hmm maybe i'll just have to rerun the line how it was and put the check valve back in. Are there really any negative effects of running this pcv setup due to not having any vacuum to pull out crankcase vapors? The stock setup with the black box seemed to work fine for 2 years on my setup.

 

Lots of oil vapor inside your intake mani which lowers the octane rating of your fuel and excessive crankcase pressure are the only bad things that can happen.

With excessive crankcase pressure, it can ruin piston rings and sometimes....blowout seals like rear main, front main, oil pan, and cam seals.

Just a fyi...I ran turbo for like a year with OEM PVC setup and didn't notice anything that bad.

 

Yea on my setup i don't think i'm making enough power to have the stock pcv setup be an issue. I actually just tested it a second ago. I plugged the stock line back up to the intake mani and voila nomore vapor AT All out of the valvecover when I rev it at idle. The thing that I am wondering about is with the engine running and the line unplugged from the intake mani I can notice a small amount of vapor escaping from the black box line even at idle. Is this normal or is it something to worry about? Is this how much vapor goes into the intake manifold stock or what?

 

Ok I just checked it again when the engine was completely warmed up and I had been driving it for a minute and there was no vapor out of the line from the black box! I guess maybe before my engine was cold and the rings werent seated enough. hmm.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike1114 &raquo;</TD></TR><TR><TD CLASS="quote">If you take the line off the black box, you will get oil EVERYWHERE. IT really spits it when your WOT!!

My motor did this from day one of startup of freshly new build.</TD></TR></TABLE>

its because the valve cover has windage plates that help reduce oil loss but aloue gasses to breath. On the back of the block you dont have this so returning oil is just slung out.

 

Actually you were using Vaccum to assist in venting the crank case from the manifold in the stock configuration.

Becasue you just disconnected the hose you are keeping your pisotn tops clean and the integrity of your fuel quality good but your relief of crank case pressure now sucks, that is why it is forcing out your valve cover.

Take the line off the back of the crank case breather and plumb it into your down pipe or to a catch can with two nipples. From the other nipple of the catch can hook that up to a vaccum source. The steel or baffles inside of the catch can will "catch" the debris or oil sludge and the vaccum will assist in pulling out the crank case pressure.

 

I got a brand new build that has some pretty low miles. Everything check out good. I run a Endyn setup and it fills up with oil after about 15 WOT pulls.

I think I may have the tank a lil too low, and maybe I should use the drainback feature. I probably going to add some valve cover vents as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BodyKits NW &raquo;</TD></TR><TR><TD CLASS="quote">I got a brand new build that has some pretty low miles. Everything check out good. I run a Endyn setup and it fills up with oil after about 15 WOT pulls.

I think I may have the tank a lil too low, and maybe I should use the drainback feature. I probably going to add some valve cover vents as well. </TD></TR></TABLE>
We've also noticed this problem on JDMS1eeper's own car. He has a HUGE catch can coming off the back of the block and it fills up very quick after doing a few days of hard pulls. His build is also brand new and has perfect compression.

I guess I will just keep running it this way and dump the line off the valvecover to the ground for now since i'm too cheap to buy a catchcan at the moment

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BodyKits NW &raquo;</TD></TR><TR><TD CLASS="quote">I got a brand new build that has some pretty low miles. Everything check out good. I run a Endyn setup and it fills up with oil after about 15 WOT pulls.

I think I may have the tank a lil too low, and maybe I should use the drainback feature. I probably going to add some valve cover vents as well. </TD></TR></TABLE>

mine does the same

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BodyKits NW &raquo;</TD></TR><TR><TD CLASS="quote">I got a brand new build that has some pretty low miles. Everything check out good. I run a Endyn setup and it fills up with oil after about 15 WOT pulls.

I think I may have the tank a lil too low, and maybe I should use the drainback feature. I probably going to add some valve cover vents as well. </TD></TR></TABLE>

It is becasue of the loation of your catch can. I run the non restircted H22 fittings in the back of my B-Series like the Endyn ones. They are just in a place where lots of oil can easily get to. If the can is below those fittings gravity will fill it for you. Place the can as high up as possible in your bay and the problem should go away.

 

so how does running the pcv get oil in the intake manifold...is the pressure from the intake side less than the pressure coming out of the crankcase?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jockobo &raquo;</TD></TR><TR><TD CLASS="quote">so how does running the pcv get oil in the intake manifold...is the pressure from the intake side less than the pressure coming out of the crankcase? </TD></TR></TABLE>

That is a great question on a forced induction motor. I imagine it is.

 

you dont run boost all the time, thats why. when there is a vacuum condition in the manifold it will suck the vapors from the crankcase into the intake manifold.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by y7turbo &raquo;</TD></TR><TR><TD CLASS="quote">you dont run boost all the time, thats why. when there is a vacuum condition in the manifold it will suck the vapors from the crankcase into the intake manifold. </TD></TR></TABLE>

Well that is a given but what happens when the motor is in boost. Does the positive pressure exerted supercede the crank case pressure and keep the oil vapor at bay?

 

The problem with our boosted motors is that when we are in boost the stock pcv check valve closes up and doesn't allow any vapor to escape from the back of the block.

 

bump for more info

 

your motor is fine, trust me!