hi,

i know there are many posts about this, but i spent the last 2 days trying to understand what to do and more i read, more i get lost. i understand it can be done in different ways, too many ways for my current understaning.

i'm stripping down an ST170 engine, i'm not expert at all with engines, i'm trying to learn.. im not looking for power or anything, just make it WORK.

i would like to keep the crankcase breather open, using a plate as in the image below. i read it can have some influence on emissions, and emissions test make me worry.. so the plan is take the safest way possible about this aspect.

In image link

i did a collage of what i understood reading different forums.. retroford.. passionford..
somebody can tell me if i understood it correctly? i'm trying to use a 3 ports catch can.

i'm also looking for a "idiot guide" to zetec basic modifications, there is one around?
i have a mechanic that can help me about other aspects of the rebuilding but he is more used to think in terms of "replace the broken part XXXXX with the same XXXXXX part". in my country modifications are mostly, illegal.

thanks,
David

Them plates are not the ideal solution. Like no plate at all there are plenty that get by with it but others don't depending on how heavy the engine is breathing and what your doing with the engine.

The problem with them is there is no way to separate the oil from the vapour.
If the engine is breathing a lot and you are chucking the car about them it will push the oil out.

I usually use the factory separator and remove the pcv valve and pipe it to a catch can or use it as ford intended piping it to the inlet manifold.

Manufacturers haven't been allowed to vent to atmosphere for years. I haven't checked the Iva requirements to see.

[Edited on 11/5/21 by big_wasa]

hi big_wasa, i read your comments about this topic in old post in the last days.

i have very modest plans for this engine, if my car will ever hit the road.. first target is get IVA, second ... "tourism" driving. no racing, no drifting, no monster power, nothing like that for sure. for me stock power is more than enough.

there is an ideal solution?
leave the stock stuff, as in understood from this document is useless:

original application is only activated via the ECU for emission control purpouses under certain running conditions

if this is true, and no better solution... now i understand better why people blank it.
if other people passed IVA emission tests with hole blanked... should pass also mine.

David

re-reading your answer, after your edit. i think i understood what to do.
i will do as you suggested.
thanks you very much.
D

[Edited on 11/5/21 by davimora]

i updated the diagram.

here is the v2

is what you suggested?

I think you have mislabelled the PCV valve? Your diagram suggests it is the cam cover breather?

I have an st170, and it breathes heavily over 6500rpm. But using the OE separator is ideal (the plate type just had oil pumping out) and I feed that to a catch tank, along with the cam breather. No filter on the tank. But an outlet to the air filter box, to give a little vacuum and help prevent the engine pressurising.

I get a smidge of water in my catch tank, that is all.

hi cliftyhanger,
yes, top-left "PCV" is wrong, i copied the image from a catch tank maker website.

quote:

---

But using the OE separator is ideal (the plate type just had oil pumping out) and I feed that to a catch tank, along with the cam breather. No filter on the tank. But an outlet to the air filter box, to give a little vacuum and help prevent the engine pressurising.

---

https://images.app.goo.gl/VC3RwuJnwRW8FrqHA

Pcv

[Edited on 11/5/21 by big_wasa]

Early zetec's had much more complicated breathing systems with ecu controlled solenoids for exhaust gas recirculation.

The basic pcv just requires a vacuum to pull it open and purge the crank case.

[Edited on 11/5/21 by big_wasa]