Oil Catch Tanks...

[Guest Eamon]

Ok can some one clear this up what is the correct way to run the catch tank people on toyotagtturbo forum have uploaded loads photos (ive posted) and then people talk about guting the pcv valve....

Now what is the best way/ correct way...

[Kennedy]

I thought it was supposed to connect to the breather and pcv.

EDIT:

Found this which was posted a while ago

Thread

[enzo_e492901]

The bottom pic is right... when there is vacuum in the manifold the vacuum draws the blow by through the catch can, catching the oil. You still need the PCV Valve.

Gavin

[Guest Eamon]

Ok well that diagram seems different from any of the photos i posted, Can people just post up the ways they done it

[Russleh]

can someone translate that bottom diagram into a proper picture. cant seem to get my head round it even tho it looks simple lol

[kevink]

First of lets get somethings clear. (Got info from Wiki, correct me if i am wrong)

What is a pcv valve?

The Positive Crankcase Ventilation valve.

What does it do?

Its a one-way valve that assists with the continual evacuation of gases from inside a gasoline/petrol internal combustion engine's crankcase.

What?

As an engine operates, high-pressure gases are contained within the combustion chamber and prevented from passing into the crankcase (containing the crankshaft and other parts) between the side of the piston and the cylinder bore by piston rings which seal against the cylinder. However, some amount of gas always leaks past the piston rings into the crankcase. This amount is very small in a new or properly rebuilt engine, provided that the piston rings and cylinder walls are correctly "broken in", and increases as the engine wears. Scratches on the cylinder walls or piston rings, such as those caused by foreign objects entering the engine, can cause large amounts of leakage. This leaked gas is known as blow-by because the pressure within the cylinders blows it by the piston rings. If this blow-by gas could not escape then pressure would build up within the crankcase.

How does it work?

The system relies on the fact that, while the engine is running, the intake manifold's air pressure is always less than crankcase air pressure. The lower pressure of the intake manifold draws air towards it, pulling air from the breather through the crankcase (where it dilutes and mixes with combustion gases), through the PCV valve, and into the intake manifold.

The valve is simple, but actually performs a complicated control function. An internal restrictor (generally a cone or ball) is held in "normal" (engine off, zero vacuum) position with a light spring, exposing the full size of the PCV opening to the intake manifold. With the engine running, the tapered end of the cone is drawn towards the opening in the PCV valve, restricting the opening proportionate to the level of engine vacuum vs. spring tension. At idle, the intake manifold vacuum is near maximum. It is at this time the least amount of blow by is actually occurring, so the PCV valve provides the largest amount of (but not complete) restriction. As engine load increases, vacuum on the valve decreases proportionally and blow by increases proportionally. With a lower level of vacuum, the spring returns the cone to the "open" position to allow more air flow.

At full throttle, there is nearly zero vacuum. Should the intake manifold's pressure be higher than that of the crankcase (which can happen in a turbocharged engine), the PCV valve closes to prevent reversal of the exhausted air back into the crankcase again. At this point the PCV valve is nearly useless, and most combustion gases escape via the "breather tube" where they are then drawn in to the engine's intake manifold anyway.

Conclusion

So if you are going to connect the tubing back onto the intake manifold you need a PCV valve connected or you will be pushing air back into the crank case. If you are going to let the system breath freely than you do not need an PCV valve.

Options:

So if you look at the pictures in the opening post:

First picture seems to be connected wrong as both breather pipes are hooked up to the catch can, this means the gasses can't be vented in any way at all!

Second and third picture seem to be correct, but are not your only option. They have used the method in the second layout in my picture.

You can also hook it up like the third method i have shown. This has other positive effects:

The oil, moisture and blow-by gasses do not get pushed back into the intake system and engine. They cause carbon, sludge build-up and hot air.

[Guest Eamon]

Good lad this clears some things up

[Russleh]

cheers. mines is connected to the breather in the middle of the rocker lol that will be wrong then. guess its just best to have a little filter on there then ?

[kevink]

i have a breather on the other vent cause i have a FMIC.

But its gets oily and even sprays minute oil on the rocker cover, so i ordered a oil catch can for that vent. For now i am leaving the pcv as it is.

[Russleh]

ahh thats what usually goes at that breather was rackin my brain for ages earlier trying to think of what went to that bit lol.

[kevink]

BUMPING this

read post below

[kevink]

The pcv valve only opens when there is a vacuum in you inletmanifold.

So you will have to gut it or hook it back up to your inletmanifold!!!

if you do hook it back up you must tak ein consideration that you catch can will be under pressure when you come on boost!

So actually you would have to hook up a pcv valve between your catch can and your inletmanifold!!!

[Spoonz]

i use to pcv valves, the original which had a vacum pipe goin from that to the catch can then another one goin from the catch can to the inlet manifold has can be seen in this pic posted by weejohn from tgtt

http://www.toyotagtturbo.com/forums/showth...highlight=catch

my catch can gets full of mucky oil now has wen i had it the other way like posted above it done nothing,

dont forget u have to have a breather on the rocker cover aswell

[StarletRick]

that first pic up there....

if that catch can isnt vented. hes going to blow his turbo seals in about a week ^^

also, you HAVE to remove the pcv valve. it doesnt work as a breather unless its gutted or replaces with a metal nipple.

easiest way to do it is go from the breather on the bottom left > catch can > air intake (before the turbo)