How can i... (PCV question again)

[A80Avant]

i have fitted the catch tank now,and eliminated the vapours that go to the tank.

However im still having the top rubber seal of the head get moistured by oil. I presume this happens under boost conditions.

as you can see in the photo,i have altered(sorry paul) that's the PCV system i have now at the car.

How can i eliminate the lower entrance of the tube to the camcase? i suspect that under boost conditions,the lower tube still brings vapours on the camcase and it is what causes the seal to get wet again.Most of them are going in the catch tank,but still it's enough to produce this issue again.

What problems would it cause if i had that tube sealed? That would mean that under idle and vaccum,all crankcase vapours would have to go through the PCV valve,but that would not open.would it?

[A80Avant]

could it be that the PCV valve is not working properly ? anyway to test it?

[Jamo]

You've pressurised the head. PCV also works from a pressure differential from head and block. You need to vent from the head and the block not just block alone.

Why would you go against S2centrals.net and other catch tank setups?

[newsh]

You cant block that pipe or you really will get some oil leaks.

Are you saying the cam cover gasket is leaking? If so its probably gone hard with age and needs to be replaced, you also probably need to remove the PCV Valve so it all breathes a bit easier. The next stage would be to take the camcover pipe to the catch tank too as I have done.

But bottom line is if your cam cover gasket is leaking it needs replacing and or resealing.

Have you checked that the pipes are not blocked? And the 2 valves are in working order? I'd take the whole lot off and wash then out, you get a lot of mayonnaise build up in them. If they're blocked then you'll get the gaskets leaking under boost. I had the camcover gasket blow out entirely when the tiny plastic one way valve went wrong a couple of years back, another good reason to get rid of the whole lot..

Actually maybe that little valve is leaking, that would account for your fluctuations in boost and the oil seepage.

[GazzaG60]

the reason for the can is to use it to vent the vapours there and not back to the engine so that you get no contamination to combustion mix and also to relieve pressure. by blocking it you have increased pressure and risk killing gaskets and filling the can every boost run.

unblock it.

personally id **** the carbon can right off and just run 3 hoses to the can with a filter on that.keep that pressure down

it was not uncommon for the 16vt to fill a can down the 1320. the use of beetle oil filler helps as this has an additional breather on it. it fits to the rocker cover and the cap on top of it.

[A80Avant]

thanks for the answers.

1) reason for adding the catch tank as i did(after quite a few threads and questions) was because it was easier and also it still utilises the N80 valve which the ECU controls and thus i wouldnt have any fault codes there.I thought this would just eliminate the problem with the MAF contamination and inlet tract which i wanted.I havent blocked anything.Hose to camcover is still stock. I have only rerouted the hose to maf towards the tank and then to atmosphere. (thought that would be enough since during idle and vaccum the camcover shouldt have any problems)

2) The rubber cam seal is new and replaced only 2 months ago.Also took the large pipe and cleaned it 8 months ago along with the check valve,so it is open.

3) i havent replaced the PCV valve for about 2 years,so i dont know if that is blocked. Would removing that create any issues now that i have added the tank?
Is the flame deflector needed as well?

[A80Avant]

right so if i add that pipe from the camcover directly to the tank,would that work? Wouldnt vapours during boost still go in the camcover then?

[S2central.net]

You can try taking both the crankcase vent and head vent directly to the catch/cyclone tank - bypassing the PCV valve - but it might be better to keep the valve in place as it is designed to open only when the pressure builds up to a certain level.

[A80Avant]

i will try replacing it and see if it is damaged

[newsh]

right so if i add that pipe from the camcover directly to the tank,would that work? Wouldnt vapours during boost still go in the camcover then?

The important thing to remember here is that the pressure is already in the cam cover, we're trying to let it out.

[A80Avant]

obviously for the pressure being there it means that during vaccum and idle there is no problem.right?

it is only under boost when the problem arises and it needs to be opened/freed so that fumes can go that way,rather than to the camcover.

[newsh]

The cam cover and the crankcase ARE THE SAME THING, they are connected by the oilways inside the block which drain the oil back to the sump. The pressure is trying to get out of both!


The only reason the pipe goes round and down to the T piece near the crankcase outlet is to try and get some of the oil in the cam cover fumes to return to the sump.

[A80Avant]

so in essence the small hose is a return hose then?

cause the only way i think about it is that since the large metal tube(with the PCV and check valve) is going to the catch tank, if the small tube is blocked,then all fumes should be going to the tank supposing that,that tube is open.IF the tank is creating difficulty in the fumes to go out,then the only viable way to make things work is to try and find a way to reroute the whole thing back to the MAF.However having seen what comes out of the filter and what stays in the tank,i doubt that the tank will do much good there.

If the small tube is blocked,and there is a positive pressure on the large or a partial block there,then that would explain why i see some oil residue on the camcover and really not much on the tank (but quite a bit on the oil filter)

[S2central.net]

I think you are thinking about it too much !

[A80Avant]

i know.... i just want to know what i have to do before i rip the whole car open to try to fix stuff...