Blocked PCV and new catch can


civicx3

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Ive been having a lot of oil leaks on my EG6 and think its down to a bad PCV valve so will replacing it and installing a catch can. Im not running boost so any advice on setting one up for the first time on a NA motor?

The outlet of the PCV valve goes to the intake of the catch can, but is it best to put a breather filter on the cans outlet or should i run it back to the intake?

If its best to put a breather on the outlet, do you block the intake manifold inlet?

Should i keep the outlet on the rocker cover going to the rubber intake pipe or just put a breather filter on it?

:nice:

EDIT: After reading a lot more on PCV valves i didnt realise the importance of keeping it clean and replacing it when needed. Seems like a lot of people were having the same problems as me, smoking engine, oil leaks everywhere, loss of power, pre detonation etc... All caused by this little plastic valve failing. This guy explains it quite well...

 

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Kipper

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May 27, 2008
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You shouldn't run a pipe straight from PCV because for the PCV to open or operate correctly it needs a vacuum from the Inlet manifold.

This method means you will be venting in to atmosphere.

1) Remove PCV (Pipe should run from a black breather box at rear of block to bottom of PCV and from PCV from manifold), Remove all of this.
2) Plug up port on inlet manifold using 8 or 9mm vacuum plugs (eBay this)
3) Run a pipe straight from black breather box where the the PCV used to route from straight to catch can
4) Can vent rocker cover port straight to catch can too

It's very important that your catch can breathe, Not one of those enclosed cans without a filter.
 


civicx3

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The can i have here has a option to put a filter on it but currently has it blocked and just has a inlet and outlet

wouldnt it still be under vacuum if i routed the pcv to the inlet on the can and the outlet back to intake manifold? pretty much just putting a filter inbetween the original route ( with the can not having a breather filter on )

Not sure i understand your way of routing, sounds like you're saying remove the pcv valve?
 

Last edited:

Kipper

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May 27, 2008
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The can i have here has a option to put a filter on it but currently has it blocked and just has a inlet and outlet

wouldnt it still be under vacuum if i routed the pcv to the inlet on the can and the outlet back to intake manifold? pretty much just putting a filter inbetween the original route ( with the can not having a breather filter on )

Not sure i understand your way of routing, sounds like you're saying remove the pcv valve?

So i keep the breather box to block as it was originally?

Ive got the breather box off and bought a new pcv valve ready to go on
I have removed the PCV completely on my B18C EG Racecar and just vent from the rear of the block (Black canister/breather box) to a catch can instead of PCV meaning the engine is breathing naturally rather than being under vacuum to recirculate the oily gas vapour back in to the IM. I didn't have to remove the black breather box for my setup.

If you add a catch tank in a closed system under vacuum, You are still going to circulate some vapour back in to the IM? Of which you will try and catch with a filter inside a can?

The full blown method would be to remove the black breather canister on the rear of the block and put in an OEM breather port and route from that straight in to a can. Like below.

:
 


civicx3

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im ok with a small amount going back in, it will be heavily filtered and anything is better than what it was as my intake manifold was covered in thick black tar inside

didnt realise you could buy them and do that with the block, im trying to keep my EG6 as original as possible so wont be going that far on this car
 


Kipper

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Yeh fair point about keeping it near original, An EG6 is a rare car these days!
 


civicx3

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fired it up today after replacing all things PCV related and it no longer smokes! It had a new valve, breather box seals, rubber hoses, added a catch can, removed intake and throttle body and cleaned them inside.

It was smoking like a steam train before so that shows how gunked up it was. So if your car smokes, it could be the PCV system

Also made a bracket and used the rubber grommet from a honda radiator bracket and found a blue 10 - 8mm reducer so the big braided catch can pipe wasnt pulling on the plastic end of the PCV valve

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Do1313R

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Mar 3, 2018
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Em1, ek9 rep
looks good man!!!
i just installed a new PCV and catch can as well, my car still spits out a puff of smoke when i cross over into VTEC.
 


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