PCV or not PCV

[Lawbags]

Howdy all,

At the last stages of my 2.1td conversion and in the original car, the engine ran a PCV valve.
The original intake system has long gone, so I now don't know whether to run a catch can setup, or try and fit a PCV valve.

I've got a take off from the dip stick cannister here:


and would run the PCV into the front of the air flilter here:


So it's that, or a standard catch can set up.

This is the first time I've tinkered with a diseasel, so don't know the benefits of each.

Any thoughts and suggestions?

Cheers

[GreenV8S]

It's better for the environment to run a PCV system. It's better for the engine to run a catch tank. You do, however, need to either make the catch tank self draining, or remember to drain it manually.

[mk2 24v]

Do you have room to run a catch can inline of the proposed breather pipe?
Oil filler extension housing-catch can-air filter is probably what I'd do

[GreenV8S]

mk2 24v said:

Oil filler extension housing-catch can-air filter is probably what I'd do

Be wary of the air filter.

On a PCV system the crank case has a ventilation which draws air IN, typically via a small filter. It's very common to see these sticking out of rocker covers and perfectly sensible to use a small paper filter to keep crud out of the engine.

On a car without a PCV system that port on the rocker cover is a breather outlet. Breather gases will contain oil mist even after they have passed through a catch tank. If you pass that through a small paper filter then you'll likely to find that filter ends up as a soggy oily mess. A small paper filter is a poor choice in that situation. What you really want is a strainer to catch whatever coarse oil droplets you can, and then let whatever's left go straight to atmosphere.

[mk2 24v]

Shouldve clarified, I meant the original air filter for the actual engine as the last line.
So any vapours that come out of the catch can get ingested/caught by that cone filter

[GreenV8S]

mk2 24v said:

Shouldve clarified, I meant the original air filter for the actual engine as the last line.

Ah - got it.

[Krikkit]

Lawbags said:

and would run the PCV into the front of the air flilter here:

I'd put a catch can in, then an extension which moves the filter away from the turbo, and plumb in a vent to the extension so it can breathe to/from the inlet like an OEM setup - light oil vapours, water etc get sucked out of the catch can which makes life a lot easier (a 0.5L catch can will probably only need emptying every service).