After doing a little research on Google, I also found out that PCV valves don't operate fast eough to achieve the vacuum effect that the Krankvents do.

 

well after about 300 miles and a lot of vtecing, my oil level is still perfect. you can barely hear the popping noise unless ur standing near your hood. so far this was a very worthy purchase.

 

This is (how I think) it works:
#1 = your OEM PCV valve.
#2 = air flow into the crank case (filtered by air filter)
#3 = intake manifold where vacuum is when the engine is running (most of the time)
KV = Krank vents both installed in the same direction of flow

The Krank vent in line with the OEM PCV valve does the same thing :allow flow in only one way.
The second krank vent doesn't allow air flow into the crank case, it blocks the air flow #2.
The intake manifold keeps sucking air out of the crank case at #1 and you create a vacuum.
That second krank vent does allow flow OUT of the crank case when needed.

The enlagered drawing of the Krank vent is not how it looks inside, there is no spring and no ball as far as I could see.
It is basically a check valve, and the drawing is a basic check valve too.

The principle is the same and they work the same IMO.

I do not know what is inside a Krank Vent, it looked to me as some kind of disk, fit very snug into the alu housing.
I think there are grooves inside the housing that allow flow when the disk is moved to one side and the disk closes the grooves when it moves to the other side.
That disk moves by difference of pressure, it moves to the side where is less pressure, like a piston and it may move very fast as there is nothing attached to it.

After searching online I also found that PCV valves limit the flow (in the direction of flow) too, I'm not sure the Krank vents do as well, I'm not sure its needed.
It may be needed to allow sufficiant flow out of the crank case, but I think the Krank Vents allow sufficient flow out too.

 

so the main purpose of these are to prevent oil burning? my 02 i just got i put 1100 miles on it non stop except for gas from ohio to fl and didnt burn a drop? i guess maybe its more beneficial if you have oil burning problems?

 

I think it has more to do with the piston rings on the AP2.

 

SpitfireS, your description is wrong. It shows air flow flowing into the valve cover from the front KV. If this was the case it would never create a vacuum. The front valve cover KV has to be reversed so that it remains closed under intake vacuum conditions.

 

fperra Posted on Dec 12 2006, 03:55 AM
The drawing of the engine is a bit different then the actual situation.
The tubing with the white arrows is the front valve cover inlet without the OEM PCV valve.
The tubing with the black arrows is the inlet with the OEM PCV valve.
Both Krank Vents should be installed in the same direction of flow, IOW, open away from the crank case/valve cover and closed towards.

The Krank Vent in the tubing with the black arrows should be installed as drawn.
The source of the vacuum is the intake manifold.
When there is a lower pressure in the intake manifold then in the crank case the intake manifold starts to suck air out of (away from) the crank case and to create a vacuum in there. When the pressure is higher in the intake manifold then in the crank case you do not pump air into the crank case because the Krank Vent (and the OEM PCV valve) are closed.

The Krank Vent in the tubing with the white arrows should also be installed as drawn.
In this case the "source" of the vacuum is the crank case itself and you don't want to let air in to get rid of that (like in the OEM situation).
When the pressure in the crank case is lower then the pressure in the connection tube between the air box and throttle body the Krank Vent stays closed and will not allow air flowing into the crank case, it is closed towards the vavle cover => a vacuum is mainained.
With a running engine there should be no flow through the metal pipe, no flow going into the crank case.
Only in certain situations there is an outward flow there (through the metal pipe) to release pressure from the crank case into the tube between air box & throttle body.

 

just to clairfy things, since im kinda new to these krankvents,... does this mean it would be unnecessary to run a catch can??

 

You're comparing apples and oranges.

 

importkid Posted on Dec 12 2006, 06:34 PM
They both grow on trees.
They both have the same shape.
Their weight is about the same.
They are both "fruit" IIRC.
You can squeeze the juice out of both of them and drink it.
You can mix the juice of both of them with "hard liquor" to have a lot of fun.



Anyway..

a_zepeda926 Posted on Dec 12 2006, 06:21 PM
A set of Krank Vents creates a vacuum in the crank case.
Basically they are check valves, IOW, allow-flow-in-only-one-way valves.

An oil catch tank is basically a seperator.
It seperates the oil from the air that is being sucked out of the crank case.
So you get less oil (vapour) going through your throttle body & intake manifold.

I think.