Club 80-90 Forums

does anyone know anything about the breather systems a 1986 engine i got a new lump fitted and the guys arent sure where the pipes are meant to go an when they connect them all up the oil gets blown out every where.
there is a pipe which comes up from the turbo to the airbox an off of it there is a smaller pipe with a tee piece the tee piece then goes up to the rocker cover breather an also onto the pressure release valve,but in the past someone has made there own tee piece with a plumbers fitting an i think this is the problem but am not sure ,it looks to me like the pressure from the turbo is going up to the rocker cover an not into the release valve , not sure if the teepeice should be some special part that i dont have which deflects the air into the release valve rather than the rocker cover
any help would be appreciated
cheers craig

Presumably you have a JX engine, if so, the cam cover breather hose should connect to the air intake hose just before the turbo. The air dump valve can also connect to the air intake but is also fine just venting to atmosphere which is the case with mine. Where is the oil actually coming from, the breather hose shouldn't really have any oil in it , have you got the round oil trap on top of the cam cover ?

hello thanx for your reply, the oil is being blown out from the dip stick because its like pressure from the turbo is going into the rocker cover through the breather,rather than into the dump valve ,i had the pipe to the valve off but when the turbo was boosting the air was gushing out an it felt like the turbo was loosing some of the boost ,but there ws no oil ,i do have the round oil catcher on my rocker cover breather, not sure if the tee piece to the valve should maybe be like a one way valve or something to stop air going back into the rocker cover ....................stressed out craig

Where are you?

People may come and help if you let us know.

The relief valve on the end of the intake manifold should vent to atmosphere.

The breather on the rocker box should vent into the inlet manifold before the turbo.

The rocker breathers can get blocked, so if in doubt drill holes in the gauze and make sure it 'breathes' freely - there should be no restriction if you blow through it.

While you're at it replace the cork gasket on the rocker box with a Corrado 8V rocker box seal - it's a rubber one that works loads better. If you get an Elring one it should come with studs that don't have shoulders - otherwise it won't work!

hi we are in dundee in scotland , the pipe from the rocker box does go down to the inlet manifold but in the past someone has put a tee piece in it. do u think it just goes straight down to the inlet manifold without the tee piece ,also the relief valve has a connection for a pipe, should this pipe just be takin down an vented underneath the motor ??
cheers craig

its like pressure from the turbo is going into the rocker cover through the breather

No thats not the case, that pipe goes into the inlet side of the turbo (which is nominally atmospheric or lower) ~ the pressure is coming from blocked breathers or piston/ring blowby (wear)... OR you are overfilling it with oil (easily done, if anything's been modified and the dipstick or dipstick tube is not bona fide original for that installation.

Can't say about the Tee-piece unless you say what else is connected to the other side of the Tee...?

Mine doesn't go into a tee piece, though if it did - I'd know where to point the extra pipe- into a cannister that could breathe back out.

AS DH says, the BOV in the inlet manifold can vent to atmosphere locally, no need for a pipe, mine is plugged internally anyway as I'm over-boosting.

right i just been out tinkering again ,the breather from the rocker cover goes down to the inlet pipe at the back of the turbo ,from that breather going down there is a t piece ,the pipe from this t piece goes on to the pressure release valve, now when i start the motor it runs fine no oil from anywhere ,great, but when i drive the thing an the turbo is boosting the oil is blowing out onto my alternator an all over everything,now if i disconnect the the pipe from the release valve going into the t piece the motor goes fine apart from when the turbo is boosting,not at first but after some boost then there is a whooshing sound like air gushing out an it feels as though the boost from the turbo is being lost ,but there is no oil leaking out ,wondering if the problem could be with the release valve but not sure if this would cause oil to blow out ,right im away to wash me hands any help much appreciated
cheers craig

Sounds like it could be a blocked rocker cover breather - builds up pressure in the engine and then releases it and hoses the oil out with it.

Do you have the splash guard on under the rocker cover (you can only see this if you have the rocker box off)? In motion if this isn't present there could be excessive splash causing similar symptons.

It's also possible that the rocker box isn't sealing - if that's the case then it'll leak under load again. Be careful when tightening the nuts down as it will distort easily and constantly leak if you bolt it down too tight.

How new is the 'new' motor?

Clive please use unabbreviated terms prior to abbreviating them so we can be sure what you're on about - BOV won't be instantly obvious to everyone (blow off valve).

Thomas, get real..

the BOV in the inlet manifold

Are there any other valves in the inlet manifold?
Haven't we been talking about the valve in the inlet manifold already, that simply vents to atmosphere, ?

It's just sloppy not clearly showing what an abbreviation started out as.

What can I say, I would have expected you to stick to that sort of well established convention.

Sloppy, tsk

OK, so last week it was my sentences were too long and explicit and now this week my attempt at shorter ones has failed the Thomas test...

John, apologies

BOV = Blow Off Valve

Something I think I'm in need of more than your diesel engine

not sure about the splash guard inside but i dont think the breather is the problem because the motor drives ok when the breather is disconnected no oil just the same gushing of air when the turbo is boosting,i also cant see any oil leaking from round the rocker gasket which was replaced when the motor was fitted , i think the motor came out of a golf about 1989 i think , my freind is a volkswagen mechanic an is also baffled by this problem , im away to the local plumbers merchants to see if i can get a y piece instead of a t piece from the pipe which comes from the release valve as i think that some of the air coming from the release valve may be going back up the rocker breather through the t piece hoping a y shaped fitting may help
fingers crossed craig

Why would a Y piece instead of a Tee piece make a difference - pressure is pressure - direction and shape have no bearing on it.

There's still a few unanswered questions from above... what is the other line from the Tee piece doing, where is it actually going?
Do you know how much boost you're getting?
Could the engine be worn and this be blow-by?

The plumbing though, does seem suspect... but 'all' breather lines seem to need checking for bloackge first.