john banks

There was a puddle of oil on the left chassis rail from the breather that comes off from the centre of the block on the EJ257. Anyone know how this is connected OEM as I am a little tempted to block it off. The other breathers are behaving immaculately considering the mileage and usage

Denmark

iTrader: (2)

On mine i connected the extra crankbreather teed into the oe one,and then went to atmo,

And it works great


Skassa

Pavlo

I would, it will get splash off the crank. The OE system probably has a separator in it.

Paul

john banks

I need to confirm from the service manual but it sounds like the two new breathers on the heads are T'd together and join the new breather on the crankcase, with the other breathers working as before. Apparently this equalises the pressure between the crankcase and the heads, which I thought was a no-no hence the need to confirm.

Andy.F

This makes sense then all the breathing is done via the vent which has the internal baffle/separator chamber.
There may also be further benefits to this set up as the majority of the breathing comes from ring blowby, closing the loop back to the heads will create an airflow circulation from the crankcase centre vent -> Heads -> Sump -> Baffled vent. This will improve the oil drainback from the heads compared to the std set up where the oil return and blowby gasses are contraflow.

I believe poor drainback from the heads contributes to the big end problem at high rpm by reducing the sump level.

Andy

harbering1

john how did you conect the extra breather.
My 2.5 sti engine is ready to drop in the car
I don`t know how to conect the extra breahther on the engine.

Regards
Pascal

Callum Ferguson

iTrader: (1)

Hi John,
Any chance of one or two pictures to aid the discussion? Hope you're getting the gearbox/clutch problem solved.

cheers,
callum

Bob Rawle

As an observation I use this block in my STi5, well my block has the extra breather ... just blanked it. The STi9 does have it as well and it is connected to the heads as a separate link to the "normal" breathing, I have no oil collecting in the intercooler at all (STi9) so maybe this gives a clue. In practice you need the twin breathing rocker covers to make use.

bob

john banks

Just blocked mine in the end reaching the same conclusion Bob given that I have the old style (STi 5) heads. Andy thought that the new dual system was quite good in that the crankcase ventilation also assisted return of oil from the heads.

The particular breather we are discussing is very oil indeed because it has no baffling underneath and just gets oil flicked up from almost above the crank.