Crankcase venting/catch can issues 4AGZE

[craigy]

hey guys,

I was at winton attending a drift meet on the weekend and the car was running sweetly up until the point the catch can was overflowing with oil!
It appeared to be quite clean, to the point where i considered reusing it...but i didnt of course. About 2 hours later after a number of runs, the supercharger stopped and i heard a rattling under the engine bay.
I pulled into the pits and my dipstick had blown out of its holder and was sitting behind the headlight! The dipstick had chewed up the s/c belt and oil sprayed all over the bonnet and throughout the engine bay. I rechecked the catch can and it was empty.

Have I got a blow by problem or do i need to reconsider my crankcase venting system?

at the moment i am using a cheap "autobarn special" catch can fed from the rocker cover feeding back through the sealed can and back into the inlet before the throttle body.

[roadsailing]

i'd just vent the can to atmosphere, see if that makes any difference

[celica_john]

does it have a pcv valve? have you tried cleaning that out?

[celica_john]

also check none of the hoses are blocked - i've seen that before!

also is it plumbed into the intake before or after the supercharger?

[MWP]

Blowing out the dipstick is obviously a sign something is blocked up.

But...

at the moment i am using a cheap "autobarn special" catch can fed from the rocker cover feeding back through the sealed can and back into the inlet before the throttle body.

This isnt how the PCV system should be setup.
The factory PCV system isnt just for emissions, it has other uses as well like cleaning out the crankcase air (keeps oil clean) and stopping oil leaks.

I suggest you go back to the stock setup, but put the catch can between the PCV valve and the inlet manifold (vaccum side of the TB).

[craigy]

correct me if i'm wrong but i dont think it has a PCV valve. I dont think the factory setup run to the vacuum side of the intake either.
I know the lines and feed into the manifold isnt blocked, because I took the hose off the rocker and blew in it and it was fine. A friend with a turbo sprinter on the same day had his catch can venting to atmo and he had no oil in his.

[roadsailing]

4AGEs dont have PCVs if i recall correctly, mine didnt work properly because some dick cut and shut it wrong, and it was on the vacuum side of the TB instead of on teh atmosphere side.

are you running a non ZE style inlet manifold craig? i cant remember.

atmo venting FTW!

[30psi 4agte]

1 x vote for venting the can to atmosphere

[YLD-16L]

I run a 3/4" line from one cam cover to a catch can, and then a 3/4" line from the can to my intake (pre-trubo). The can has a 1/2" line to the sump as an oil return.

This setup has been on the car basically unchanged for about 6 or 7 years (except for a few times where I just vented to atmo) and has not had any issues at all.

Your setup sounds like it should be doing the job well enough to stop the dipstick from blowing out. Done a compression test lately as it sounds like a hell of a lot of blow-by to do what it's doing.

[Hen]

I concur with Wild. Your catch can setup is right.

I've not seen a PCV valve on a ZE. It must vent BEFORE the throttle (the line out of the catch can shouldn't see vacuum or boost).

Maybe your rings are really stuffed. Try a compression test.

Hen

[lexsmaz]

Doesn't sound good, but the first question i have is, how long have you had that setup for with the plumbing & catch can etc ... & have you been out to previous drift days with no problems?, if the problems are only now, i would say it sounds terminal, but also check, yourself take off all the breathers & start up & run the car, warm it up & give it a few hard rev's keeping an eye on the breather outlet in the rocker cover, Not very accurate but gives you a bit of an idea ... you should see little to no smoke .... If it pours out like a chimney thick column also with a fair bit of pressure, Then its obviously not good... Also as stated, back it up with a compression test, make sure you do a comparison to all the other cylinders, ideally no more than a maximum of 10% difference across them all, should be closer to 5% ...

[takai]

The GZE has the crank case venting pre throttle when stock. It goes into a pipe which sits ontop of the throttle body.
You can see where it connects in in this photo:

The blue pipe is where it goes.

[ed]

i think youd be suprised with the breather sizes required to effectively ventilate an engine on the track... blowing your dipstick out is clear indication that your current veltilation is insufficient. you need to vent the crankcase AND the head separately, have an atmo vent, and a one way valve setup to prevent indrawing and pressurisation

[takai]

FWIW my 4A is running fine on the track with a pair of 9.8mm (3/8") breathers to can to atmo. Has 2L of breathing room though before it fills.

And my tolerances are probably a bit tighter being a dedicated track car.

[YLD-16L]

The last ZE import I had hold of was very worn and was a terribly heavy breather, it sounded a lot like Craigs one. Nothing short of a rebuild was going to fix this one.

Mine with a single breather in 3/4" as mentioned previously is fine on the track. I have been running a clear hose from the can to the intake lately at the track to see if the can was draining adequately and not filling and pumping oil into the inlet. It has been perfectly fine with nothing more than a very little oil mist condensed on the walls of the tube.