Oil catch can, whos fitted one?

[Doogle]

Hey all,

I have been thinking about fitting an oil catch can. How does it work with the PCV system? I have seen it setup on some but not sure how it works, my impression is the PCV almost sucks the vapor out of the block.

 

[Big Ben]

@Yiannis197 might be able to help. I’m sure he has/had one

 

[Daverb]

Me. Coke can

 

[Doogle]

Me. Coke can

Any pics?

 

[steve11]

Here’s pic of the one I fitted to my 200:



And the one I fitted to my 275:

 

[Doogle]

Here’s pic of the one I fitted to my 200:

View attachment 125927

And the one I fitted to my 275:

View attachment 125929

Steve, so to get the plumbing right, one end connects to the outlet on the back of the engine and goes to the catch can, the other hose runs from PCV valve to the catch can?

 

[TB Rich]

You don't have to route back to the inlet manifold (well to stay road legal you might have to) as it is preferable not to really. I run a catch tank without routing back to the inlet, as the oil vapours do nothing but dilute the charge and cause more knock sensitivity. Not such a problem if you're at standard compression (mine was higher comp), but it's not for performance reasons they route the vapours back in - it's part of the emissions systems for crankcase vapours etc.
If the catch tank has a proper substrate for slowing and cooling the vapour to collect the oil properly, then you can route back to the inlet as it should be pretty much clean air, however most catch tanks are just empty voids, in which case I'd not route back to the inlet. Stick a breather filter on one of the ports off the catch tank, or something like a Mocal tank has a breathable lid.

Shameless ITB pic aside, but you can see where mine is mounted currently at the back where the airbox would normally sit. This is not routed back to the inlet - as there is no where to route it for a start anymore! - but as said even on the plenum I did not route back to it, and I used a silicone cap on the port off the plenum to blank it.


Cap on plenum:

 

[Doogle]

You don't have to route back to the inlet manifold (well to stay road legal you might have to) as it is preferable not to really. I run a catch tank without routing back to the inlet, as the oil vapours do nothing but dilute the charge and cause more knock sensitivity. Not such a problem if you're at standard compression (mine was higher comp), but it's not for performance reasons they route the vapours back in - it's part of the emissions systems for crankcase vapours etc.
If the catch tank has a proper substrate for slowing and cooling the vapour to collect the oil properly, then you can route back to the inlet as it should be pretty much clean air, however most catch tanks are just empty voids, in which case I'd not route back to the inlet. Stick a breather filter on one of the ports off the catch tank, or something like a Mocal tank has a breathable lid.

Shameless ITB pic aside, but you can see where mine is mounted currently at the back where the airbox would normally sit. This is not routed back to the inlet - as there is no where to route it for a start anymore! - but as said even on the plenum I did not route back to it, and I used a silicone cap on the port off the plenum to blank it.
View attachment 126022

Cap on plenum:
View attachment 126023

Thanks for explaining it Rich. I think my concern was that from what I have read about a positive crankcase ventilation system (and I may havr interpreted it the wrong way) is that the vapours are pulled out and pushed into the inlet by the PCV. I know the vapours will naturally rise out but as the best place to mount it seems to be by the main engine mount on the offside thats a fair bit of hosing. I was worried the hose would clog?

I was intrigued to see why Steve11 has rerouted it back into the inlet as opposed to the atomsphere via a filter?

My cars on 117k now, anything I can do to help preserve power and gain any little bit is a good thing.

 

[TB Rich]

yeah I suppose as the port on the plenum is pre TB it will always experience vacuum on the PCV pulling the vapours, I would assume the widget on the side is some sort of restrictor valve mind as it would seem like a substantial amount of pull otherwise?
I also remember Ashford told me that on their high spec engines that make more power and rev higher they actually weld a larger -10 AN fitting on to improve crankcase breathing, however for more regular specs the standard elbow off the back is apparently large enough to do the job just fine.

While I was at Pure I got one of their fancy billet crankcase covers with a -10 AN fitting on it, but tbh it was purely for the shiny-shiny and not as I felt I needed it as such! Nice having a proper AN fitting too as it meant the hose could match the fuel and oil lines which are being done in ProGold black & gold crimped fittings. I'll get some pics when the catch tank is re-installed and plumbed back in.



I'd guess the long return Steve has would not block but just in winter and short stop start journeys you'd get that oil/condensation build up in the line, goes a bit like mayonnaise. Probably not a problem for Steve mind as he's in Australia!

 

[Doogle]

Id definately rather go for a simpler setup, one hose to a can with a proper system to vent to the atmosphere. Theres so many different sizes, any recommendations?

 

[TB Rich]

Get 1ltr as a minimum tbh. Assuming you're not racing, as some regs I've seen call for a 2ltr minimum if not running back to the inlet manifold.
Mocal makes life easy with it's breathable lid, plus a few different anodised colours never hurts Although I'm quite the fan of Radium stuff now, fantastic quality to the parts and machining.

 

[Daverb]

They do cost a fortune though.

The Clio Cups used this:



If you want bling go for bling but it doesnt need to be anything fancy.

 

[TB Rich]

Builds a race car with a sequential box(?).....uses milk bottle and zip ties for breather tank You're right you don't need 'fancy', but then there's just plain ghetto too! lol

 

[Daverb]

Yeah Renaultsport must have been painting somewhere lol