Smoking ABY Avant

[S2central.net]

That's it. On idle, there will be more negative pressure on idle, all oil mist will be drawn back into the crankcase. Under boost, the one way valve connected to the block closes, preventing the crankcase from being pressurised.

And where do you think the crankcase fumes would go under boost if the valve closed ? I don't understand the thinking here.

It's a trick used on rally cars, but they fit the vacuum line to the dipstick tube as opposed to the block as described above, but not practical on a road car - you'll need to remove the connection each time you check the oil level.

I've never seen that done on a rally car before, and I've worked on a few... The norm for oil breather conversions on motorsport engines is to use catch/cylone/breather tanks that separate oil fumes from the airways.

Paul

[BRY]

Bry has an RS2 airbox for sale.

No I don't
BRY has an RS2 airbox for his own car

[newsh]

The 3B already has a one way valve, it's purpose is to allow the inlet vacuum to scavenge the crankcase when not on boost and to close when on boost to avoid crankcase pressure, if its working properly, its just under the Idle stabiliser at the back of the head, its a little plastic thing and lives at the junction of two different size pipes IIRC and is hard to spot. When the car is making boost the system gets suction from the MAF - Turbo hose ( which of course is sucking like mad when the car is boosting) If this little valve is broken there will probably be oil leaks from the Cam cover and or other places and perhaps poor scavenging at idle. Pipes to and from it should be checked too.

[newsh]

No I don't
BRY has an RS2 airbox for his own car

I have an ABY box I dont need..

[S2central.net]

The 3B already has a one way valve, it's purpose is to allow the inlet vacuum to scavenge the crankcase when not on boost and to close when on boost to avoid crankcase pressure, if its working properly, its just under the Idle stabiliser at the back of the head, its a little plastic thing and lives at the junction of two different size pipes IIRC and is hard to spot. When the car is making boost the system gets suction from the MAF - Turbo hose ( which of course is sucking like mad when the car is boosting) If this little valve is broken there will probably be oil leaks from the Cam cover and or other places and perhaps poor scavenging at idle. Pipes to and from it should be checked too.

John - I know the valve you are talking about... Ehh you needed to have seen this one in the flesh to believe it - the breather pipe which should have extended from the front of the (ABY) rocker cover to the MAF hose (to allow the crankcase fumes to be ingested by the engine under boost) was disconnected ! It was an open pipe to atmosphere as far as breather fumes were concerned.

An attempt to block the hose on the MAF side had been done by clamping the metal hose end in a vice - this wasn't airtight either.

Paul

[volcano rs]

the beans are spilt

[Jamo]

the beans are spilt

Volcano RS: **** Turpin

[volcano rs]

you know that! even he had the decency to wear a mask nice pic i'm sure frank would enjoy this .

[spink]

cough,cough time for another user name change/move to a hot sunny country such as Greece?,no but that would be ridiculous :mischeif: