7A Oil Catch Tank

[Tom_]

Hi guys, i am thinking about buy a custom Oil Catch Tank, but i dont find anything about aplication on 7A (CQ20V) engine. Do you have some experience with instalation on N/A 7A engine? Or any ideas how install or which place use to install it? Thanks lot

[steve briance]

On mine i am lucky enough to have the metal crank case breather conversion so no squishy hoses. This also meant it was dead easy to change the direction of the outlet and send it towards the front of the car. I remember cutting and shutting the curved section of the outlet pipe to achieve this, it was a piece of cake to cut and re-weld swivelled through the necessary to get the angle right. Lick of paint and you would never know!

My catch tank sits under the radiator cowling next to my headlamp.

Rubber hose runs from crank breather and goes through a small hole made in the side of the vertical plastic shield at the side of the rad like the power steering hose.

Blocked up the large hole under the air intake hose with a billet of round aluminium i happened to have had lying around for ages, secured in place with jubilee clip.

Up to you and the tank you have as to how you fix it to the car but mine was tall and thin and is held with nut and bolt onto the front panel.

[Tom_]

Any pictures of your installation ? Thank you

[Rusty]

You want a swirl pot over a catch tank. Run a coke can sized tank over the crank case breather with an inlet on the side from the head and an outlet on top to the metering head or wherever the original goes. Disconnect any hose that goes to the inlet manifold to prevent it bypassing the tank.

You can run a catch tank on the return line if you like but it won't do much unless your engine is totally dead.

[steve briance]

I don't seem to have any pics in the library so will have to try and get a lens through the pipe and wire mess on that side of the engine to take some at the weekend...

Swirl pots seem to be for coolant and fuel, I googled to see what the difference was and from my brief browse; most sites mentioned oil <vapour> catch tank under the bonnet along with a separate coolant swirl pot. What exactly is an oil swirlpot swirling if it is connected to the breather system? The coolant ones actually had spiral baffles inside which looked pretty cool!

The tank i got works by providing baffles for the hot vapour to bump into and cool against, it then condenses back into oil and runs down into and is 'caught' in the tank. The other end of the tank is vented into the atmosphere. yes yes, i know this wouldn't meet euro whatever emissions standards but boy is my throttle body and inlet tract clean as a whistle since fitting the tank!

[Rusty]

Having done a lot of research, spent many £00s developing, testing on track and selling kits for S2s, I can assure you swirl pots have a place on a proper oil breather system. Many OEM systems use them and they have one huge advantage: the oil stays in the engine and not sat in a tank doing nothing.

Baffles are a good plan in a catch tank for the reasons you site. A swirl pot does a similar yet different thing and should drain back to the sump.

You can run a drain from the catch tank back to the sump but with tanks being larger, they tend to be mounted further from the heat of the engine and so condense water, as well as oil which isn't ideal to drain back in to the sump.

[steve briance]

that seems like a pretty clear explanation!

So, similar but instead of keeping hold of the oil, the swirl pot drains back into the engine. Makes sense really as its always a surprise how much oil there is in 'vapour', it builds up in the tank and by not being in the inlet it makes the difference known by how clean it is in there now :-)

Cheers!

[Rusty]

The other thing that affects the longitudinal I5 motor is the fact that on most tracks, the breather is on the side the oil heads towards when cornering. I've seen people fill 1 litre catch tanks in 10-15 laps! With a swirl pot: a few drops and that's it. The problem isn't helped by the head breather location, sticky tyres or a madman behind the wheel...