Catch tank

[Rusty]

Just ordered a custom catch tank for my S2.

Having looked at the breather system I have decided that I'm going to intercept the breather where the PCV valve is and then use the existing pipework to feed back to the inlet. This should make for a very neat installation and removes the problems with the carbon canister solenoid.

The other option is to run a pipe along the strut brace and feed the carbon canister into it. Either way the breather system remains sealed and feeds into the inlet as I'm happier doing this.

I've made a very rough sketch of the tank and have asked about getting others made in the future so see how it goes and I'll let you all know!

[Rusty]

Right, just had a good look at this and am starting to get more of an idea of what's required.

I didn't realise that the breather released into the inlet manifold. Should I remove this and just connect it to the inlet pipe or should I leave it connected?

I've read that a new PCV and flame trap are a good idea. I'll get new ones on order if I need to keep them in the system.

How is the PCV supposed to operate, I can't see what it does / how it works.

[mcandmar]

Everybody has there own opinion on this, most want to remove the connection to the inlet track to prevent oil from being blown into the turbo and intake. Personally i would rather leave it in place as the vacuum helps suck out fumes and water vapor from the crank case. The best solution IMO is to fit a separator in between the crank breather connection and the inlet track, that way everything works as before except for the heavy oil being filtered out before it reaches the inlet. I'm also not a fan of draining the catch tank back into the sump, if its been sucked out of the crank case it should be disposed of IMO. But as i said, everybody has their own theory's on this.

The main difference is a separator vs a catch tank. Most catch tanks are just an empty box, where as a separator has a series of baffles or a spiral path to separate the oil from the fumes as it passes through.

Oh and PCV valve is basically just a one way valve.

[S2central.net]

The PCV is there to treat blow-by gasses... Every engine has a certain amount of blow-by the pistons that gets into the crankcase. Left untreated this would build up pressure in the crankcase, and unburnt fuel will dilute the oil over time... So these crankcase fumes have to escape. The old school method was to just vent them to atmosphere - usually by some kind of filter to catch worst of the muck, but these aren't allowed anymore by green regulations.

Most non-turbo cars simply recirculate the crankcase fumes to the airbox or IM as they are always under vacuum. You often see these systems gunged up where the crankcase fumes condense and dump the oily muck into the airbox.

On a turbo car like ours, we cannot dump crankcase fumes into the IM, cos it might be under pressure - hence why they get connected to the side of the turbo that is always in vacuum.

Carbon canister fumes are controlled by the EVAP solenoid on the ECU. These are vented to the IM cos the ECU knows when its boosting or not.

The actual pressure valve on the crankcase is designed (IIRC) to only open the vent at a certain amount of pressure - can't remember how much but would be easy enough to test.

The flame arrester is there to stop any backfire scenario from having the chance to propogate a flame into the crankcase...which could be nasty.

[Flat on my back]

.

Wot happened to that funny 'thingy' Jamo found...was quite big but looked a good seperator device.

[Rusty]

Cheers. Where does the flame trap go? Is it part of the PCV or is it further up the breather?

I took the PCV valve off and it didn't seem to be one way, not that I could get to operate, so I think it's knackered. A new one should sort that out.

I've located the solenoid and IM section and have got a better understanding of what it does. Are there any tests to make sure that the solenoid is working correctly? I've had a bit of a random boost leak shown by a fluctuating boost gauge, I wonder if this could have something to do with it... might block it off and see if I still have the problem.

I'm going to intercept the breather at the point where the PCV valve is and the re-connect to it there too. This leaves everything as factory as possible and so should work fine. I'm not going to return to the sump for now as I don't want the hassle. If there's a lot of oil in the tank then that's an indication that I have some sort of problem, the car is using a little oil at the moment.

The tank I've had made isn't anything fancy but I might see if I can have it baffled to aid condensation of the vapours.

Just ordered some flexible silicon hose that states it's ok to use with oil breathers. It's the steel coiled stuff so hopefully I can bend it a bit and make everything look pretty

Going to give everything a good clean when I fit all of this so should be fine.

Finally, why did they have to make this so complicated!

[newsh]

Andy, there's a little tiny plastic one way valve in the hose which connects to the IM, replace that as well, this is the valve that opens when the throttle is closed and applies vacuum to the PCV system. The rest of the time it gets gentle vacuum from the MAF hose. The PCV valve is a partial one way thing, it restricts if there is a sudden increase in flow in one direction, the diaphragm in there is resting on a spring, but has a hole in it anyway..

[Jamo]

Err I 've got to ask why did you sell Dom's catch tank?

It is perfect for what your doing.

Two inlets, one from block one from top, return to sump and the to just return to turbo inlet.

[Rusty]

I sold it and then decided that I actually wanted a catch tank... silly really. This is a little different and easier to fit than Dom's one.

[Rusty]

Emailed the guy making this yesterday and it is baffled.

This is going to cost £40 delivered and he was willing to offer a discount for say 5 units so if it's any good I'll let you all know.

[terrybullwon]

Emailed the guy making this yesterday and it is baffled.

This is going to cost £40 delivered and he was willing to offer a discount for say 5 units so if it's any good I'll let you all know.

Why didnt you ask Baz to make you one off this forum?

His works excellent and will build you one to any spec.

[Rusty]

That'll be because I don't know who Baz is and so didn't know he did them....

[terrybullwon]

That'll be because I don't know who Baz is and so didn't know he did them....

http://www.s2forum.com/forum/showthr...ght=catch+tank

[Rusty]

Oh well

[Rusty]

Catch tank has been made and paid for, hose is here, just got to sort the PCV and other bits then it's fitting time!