Oil Breather Tower

[AlandAnn]

Just found this thread... can't access fleabay at work, so i'll flag it for later, thanks

[AlandAnn]

£80.00 for a straight replacement!! It's only plastic ffs. These companies should be ashamed.

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[itchyfeet]

Can anybody other than 123-jn clarify how a T3 breather tower should be tested?

If I paid 80 quid for one and it behaved the same as mine I would be p1$$€doff

£80.00 for a straight replacement!! It's only plastic ffs. These companies should be ashamed.

They won't sell many and if you knew how much injection moulding tooling costs you would realise they need to price it according to sales to cover the tooling.

[silverbullet]

If you can suck air from the small pipe on the tower that connects to the engine air intake, then the diaphragm has failed.
It is textile reinforced rubber, much like that inside a distributor vacuum unit.
I bet most breather towers out there no longer work properly.
It allows the crankcase to vent excess blow-by pressure, but not under high-vacuum conditions i.e. at idle, when oil vapours could be drawn into the engine and result in a poor idle HC reading.

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[itchyfeet]

Thanks Ian
Have you fitted these 80 quid new towers to the engines you have done?

[bigherb]

It allows the crankcase to vent excess blow-by pressure, but not under high-vacuum conditions i.e. at idle, when oil vapours could be drawn into the engine and result in a poor idle HC reading.

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It doesn't work as a PCV valve with a carb just a plain breather.

[itchyfeet]

please tell me more?

It allows the crankcase to vent excess blow-by pressure, but not under high-vacuum conditions i.e. at idle, when oil vapours could be drawn into the engine and result in a poor idle HC reading.

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It doesn't work as a PCV valve with a carb just a plain breather.

[bigherb]

please tell me more?

Look where the breather pipe is connected to.

[itchyfeet]

My understanding of positive crancase ventilation is that there is a flow of air through the crankcase but this isn't the case with the WBX

There is no ventilation, the only way in for air is around the dipstick as far as I can see.

So I don't understand the breather, it seems to me just allow volitiles to be drawn off, if so why the valve?

[bigherb]

The breather is just connected to the air filter which depending on how dirty your air filter is is near atmospheric pressure, it doesn't know when there is high manifold depression as it is before the carburettor. On the injection engines the breather is connected to the inlet manifold where there will be high manifold depression when the throttle is closed and works as a PCV

[silverbullet]

I have re-used the towers on the engines I have built. Hard to justify the 80 sovs on a new engine for so little benefit.
AFAICS the valve allows the engine to vent pressure from piston ring blow-by whilst minimizing idle emissions and allowing some oil vapour to condense and run back down into the engine.
Oil foaming characteristics and evaporation control has come a long way since the mid-1970's when the wbx was signed off for manufacture.
I intend to change my own 2500 build to a PCV system with vented rocker boxes, just like Subaru used.

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[itchyfeet]

So the main reason they are 80 quid is because nobody buys them.

[silverbullet]

The diesel ones arent cheap either...

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[bigherb]

So the main reason they are 80 quid is because nobody buys them.

Only if you have an injection engine as if it wasn't working it would cause rough idle. Or if it was blocked high crankcase pressure.

[123-jn]

Having fitted my chinese valve to the outlet of the tower, I can say that it definately reduces the flow of gases into the air filter at higher airflows but it doesn't shut off as well as the correctly working tower that I have. Under acceleration this appears to more or less close the flow off. I used clear tube with some cotton threads glues to the top in the centre so I could see which way they flapped in the flow. Using the chinese valve under hard acceleration there appears to be a reduced flow but not a complete stop. At tickover and when cruising the flow seems to be in evidence. I plan to cut up one of these chinese valves to see what is inside and how it works. According to what I have read with high vacuum at tickover the flow should be low and it is lower but I sort of assumed that was due to less blow by gases. AT high cruising speeds the flow should be high due to low vacuum and it is .(also there is more blow by)
Under hard acceleration with high vacuum the flow should be low and is almost non existant with the good vw tower.