Ok this might be hard to explain with no pictures but .....
I was looking at the intake manifold last night and where it meet with the head
There are passages from every intake runner to a center port which runs into
the head, then out the breather on the valve cover.
When an engine is in boost this would cause great boost leak to atmosphere
and additional unneeded pressure in the crankcase, which would lead to premature failure
of multiple gaskets.
Has anyone plugged this port in the head?
Im also planning on running an external oil catch can with 2 1/2" NPT ports on my valve cover
for added ventilation.
There should be a check valve in there that doesnt let boost through, just vaccuum.
Where is the valve located?
I blew thru and it went right thru the head.
Pictures of said ports? The only port from the mani to the head would be EGR...
fortune cookie say: better a delay than a disaster
Here are some pics I googled on the internet. Ports are circled in red.
But I cant find a pic of the corresponding port on the intake manifold.
Im sure you understand.
Im sure this causes boost leak ..... you can blow right through it all!
Wow, I just checked the port on the manifold and it's about the size of a pin head. You definitely won't be loosing much air through that, and it's certainly not enough to create noticeable crankcase pressure (especially with your PCV going to a catch can).
fortune cookie say: better a delay than a disaster
Yeah exactly, but I dont want to overspin my turbo to create the pressures I want.
Im going to plug mine up!
let me know how that works, because i was actually thinking the same thing. i have a bare head sitting in front of me
IM GOING TO USE A 1/8 NPT PLUG, SO I WILL POST PICS SOON.
yup plug the PCV hole. great idea.
Are you plugging it between the head and valve cover? If so, bad idea. You want to plug that hole in the manifold (just stuff a thumb tack in it).
However, like I said, it's pointless if your valve is functional.
fortune cookie say: better a delay than a disaster
Yes im plugging the hole between the head and the valve cover, should have it done today.
Then Im welding two 1/2" npt bungs on the valve cover for ventilation and running lines to a catch can.
This will vent the crankcase but not the intake where the boost pressure is.
Whet valve are you talking about, i can push and pull air through those passages.
Ok so here is what I did.
I tapped the head with 1/8" npt
Then put a plug in it.
I over sized the valve cover hole to accomodate for the top of the plug.
Then I welded 1/2" ntp couplings directly above the baffles on the valve cover for plenty of PCV action!!!!!
I'm guessing that you are gonna run both of those lines to a catchcan. Why the breather though? I would think that pressure would release in the easiest path and to me it looks like the breather is the place where it would happen. could you cut the nipple off where the breather is and then weld a nut there instead of one of the other two? Thats just my thinking, i hope this doesn't sound as bashing. I just want to make sure i know about the pcv before i go turbo.
PCV is venting the engine due to the air displacement on down strokes and up strokes of the piston.
Also on an older motor there will be excessive pison ring gap due to high milage and wear.
This will cause more blow by air into the inside of the crankcase.
If there is not vent it will cause multilpe gasket failure.
Rear main seal, oil pan, valve cover, head gasket..
The air will flow out the path of least resistance thats why I left the breather port on.
Its not going to a catch can, its going to be a open loop system, just braided hose down the back of
the block to vent to the atmosphere.
Plus I have no room underkneath my hood for a catch can, and I have a fresh never ran built motor, so im not worried
about blow by right now.
Also, the couplings are above the valve cover internal baffels, which will not allow a direct exit for oil jumping around in the valvetrain.
well i knew how the pcv system works but was more concerned for any oil that might be pushed out. If like you said you have a brand new motor then crankcase pressure wont be a concern. My motor on the other side is a little on the older side so i will be running a catch can that has an atmospheric breather.
not such a good idea ..... unless you like the smell of gas fumes.
my vent to atmosphere is going down the backside of the engine to underkneath the car close to the ground.
this will actually cause a vacuum when driving sucking pressure out of the case.
if you vent it under the hood, the un burnt blow by gasoline will vent under your hood, and come into the cabin.
*fumes* yum yum
