Venting PCV gas from catch can via breather

[Pirate]

Hi
Im going to do the EGR mod and Im thinking instead of using a catch can and sending the gas back to the turbo can it be just routed away from the engine altogether via a breather? would this damage the engine? I know its not the best for the environment but is it possible or has anyone done it?
Cheers

 

[baitfish]

Yeah mate, just put a new line on to the pvc and run it down low somewhere so the oil drops on the ground, with something like a one way valve to stop any crap going back in when then engine isn't running.

down side is you'll drip oil everywhere, not real nice, and its illegal so if you get pulled up and they spot it you'll prob get into some decent trouble.

I'd prob go about it by putting a catch can in, with a medium to condense the oil vapour, then run the outlet back to the air intake where it original hooked back in and leave it there, and blank off the intake hole.

that way you wont drip oil everywhere, and your not sucking that hot gas back into the turbo. Plus if you get pulled up, and you've plumbed it in well it should just look like its going to where its meant to go at a quick glance.

 

[ben85]

i wouldn't vent to the air, wherever u park at night will end up a big oily mess in time.
u can run it to a catch can and just vent that to the atmosphere with one of those little breather filters ontop of the can, but i didnt like venting fumes into the engine bay where they could enter the cab and be inhaled.

 

[Pirate]

So the engine wont have any undesirable effects if i blank the PCV intake?no limp mode?, I like the idea of making it look like it goes back in but just vents, I would use a normal catch can setup but Im worried if it does fill (me forgetting to empty it) and do damage to the engine

 

[bods]

They do need to breathe a bit, so if you are going to block the inlet back to the turbo off you need to make sure you have a vent on the catch can. As above though, you will still have a bit of oil vapour going through the filter so you will still end up with oil hanging around a bit. If you block the turbo side off without venting the other side you will end up blowing out the sump and rocker cover gaskets as the gas tries to get out somewhere...

They shouldn't fill up very fast, it depends how worn the engine is. If you vent it and forget to empty it you will end up with oil everywhere, lol

 

[baitfish]

i left my catch can for about 15,000kms before i emptied it and there was about 100mls max in there (I've got 200,000kms on the odo). you would have to forget for a long time to have it overfill. In saying that, the more oil you leave in the can the less effective it will be at condensing the oil vapour.

 

[Pirate]

By the sound of it its ok not to put it back in the enigine, so ill run it into a can with a filter and breather and a mock return tube then there will be absolutely no crap or gases going back and no chance of me doing damage if i do forget to empty it.
To avoid the problem of PCV gas possibly getting through the firewall, im thinking maybe i could have the breather filter away from the catch can on the end of a piece of hose that extends to the rear of the car and then maybe even have another drip catching tray under it incase some does go past the catch can?

 

[Tappet]

Not really a good idea to vent to atmosphere. The gasses coming out of the crankcase are toxic stuff and it is illegal to do so. Having said that if you were going to vent it to atmosphere back into a chassis rail could be place to go. May take the stink away from the engine compartment with the added benefit of an anti corrosion coating on the inside of it

I do wonder, that if the gas is plumbed back to just prior to the turbo. There maybe some negative pressure at that point, as the engine/turbo starts to draw air. Would this scavenging effect assist with reduction in crankcase pressure, perhaps mitigate the effects of the small restriction the extra plumbing and catch can may present??

 

[mad possum]

very toxic stuff to vent, if you like to breath that while standing around your truck enjoy. also there used to be at least huge fines for doing so, and I assume they're still around ($10k for stuff like that). just do the catch can mod properly, better in most ways.

 

[chule]

By the sound of it its ok not to put it back in the enigine, so ill run it into a can with a filter and breather and a mock return tube then there will be absolutely no crap or gases going back and no chance of me doing damage if i do forget to empty it.
To avoid the problem of PCV gas possibly getting through the firewall, im thinking maybe i could have the breather filter away from the catch can on the end of a piece of hose that extends to the rear of the car and then maybe even have another drip catching tray under it incase some does go past the catch can?

Sounds overly complicated. Just get yourself a quality catch can, Provent 200 or similar and all your problems are solved. It's legal, not one speck of oil will find its way into your turbo and the replaceable filter element is good for 80thou k's. Plus you can drain back the collected oil direct into the sump if you choose to.