j1m1z

Perrin oil catch can kit (red) unused and still boxed. change of plan so wont be using this, ( chose black ones instead to match other pipe work) paid £90. 2 weeks ago. asking £75. grab a bargain. buyer pays postage or collects.
this is a quote from andy forrests web-site on breathers and oil catch cans for those who might not know what an oil catch can is for.

Breather system


The original PCV (Positive Crankcase Ventilation)system does indeed do some good for the engine by ensuring the corrosive gasses are removed from the crankcase and replaced by fresh filtered air.
The Subaru system has two main phases depending on manifold pressure/vacuum.
Under manifold vacuum conditions (probably 99% of the engines life) there is a non return valve under the throttle body, which allows the 'blow by' vapours to be drawn into the manifold. The vapours are replaced from the vents on the cam covers, supplied from the inlet duct. This provides the circulation of air through the engine, prevents condensation, oil contamination and internal corrosion.
This is indeed a good thing and there is a strong case to retain this system if the car is a daily driver.

Under positive manifold boost conditions, the non return valve under the throttle body closes and the hot 'blow by' gasses (Note - 'blow by' tends to be a cool vapour at low power but a hot gas at high power) are re-routed via a 't' piece to the intake duct for reconsumption by the engine. The cam cover vents may also vent out during this phase.
This is where you can get oil suspended in the gasses finding its way into the induction system......this is a bad thing ! The oil coats the intercooler, reducing efficiency and causes premature det due to lowering the octane of the fuel.

It is possible to 'catch' the suspended oil in a 'catch can' This is a reservoir deigned to reduce the velocity of the gasses, allowing the oil to fall out of suspension. The oil collects in the bottom of the can and the oil free gasses carry on to be either reconsumed by the engine or vented to atmosphere. The catch can will ideally intercept all 3 vent lines although the main culprit on the Subaru would appear to be the central crankcase vent.

The return of gasses from the catch can is also the subject of some debate. If the gasses are reintroduced to the intake system then you are asking the engine to burn an oxygen free mix ! ie you are reducing slightly the amount of oxygen fed into the engine, this can only mean less power. I personally prefer to vent to atmosphere and block off the return to the intake system. There are concerns that this is not very 'green' however the vented gasses are just of the same constitution as your exhaust gasses (assuming you have a decat exhaust)

j1m1z

UP

WR1 WOZA

iTrader: (2)

Hi m8
I will have it off you ! i can collect im in Stevenage where are you i will pm u my number ! bell me to make arrangements for collection

j1m1z

now sold to WR1 WOZA

fitsandy

Hi,

I have suzuki swift sedan 1300 cc 4 cylinder 86 bhp.

Even I felt the same and routed the blowby out of the PCV to under chassis of the car using a longish transparent PVC hose generally used to connect the LPG cylinders to the LPG stoves in homes in India.

To the breather pipe I just added a 2 inch dia 1 inch deep oil soaked foam filter.

I blocked both inlet manifold hole connected to PVC hose earlier and also blocked the hole for breather pipe in the hose connecting the throttle body and air cleaner assembly.

After this I reset the ECM and thats it.

My only concern is : During non idling engine runs, vacuum in intake manifold sucks blowby fumes from engine cover but now there is no vacuum so will it effect the fresh air circulation in the engine cover ?? Of course under pressure the PCV will work and push waste gases out of the system but... earlier the vacuum from intake manifold supported this ..

Any thoughts ?????????????

You may reply directly on fitsandy at g mail dot com

Regards