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antz
Friday 2nd March 2012, 18:08
Ok guys forgive me for being dumb here but...

what is the PCV system thingy?
Why do people always talk about renewing them?

LiamT4
Friday 2nd March 2012, 18:20
I'll just give you the basic (as thats all i know lol)

The postive cranckase ventilation, is a sort breather pipe(s) that recirculates the air in the engine, mainly for emissions purposes.

People replace these, as when they start to become clogged up it can can cause issues like higher pressure causing the rear main seal to let go.

Hopefully someone will come along to a) give a better explenation and b) tell me if i'm talking gibberish!

M-R-P
Friday 2nd March 2012, 18:55
Liam has it about right, there's a seporator tank, under the inlet manifold which takes liquid from the vapour (most of it) and fumes are vented back to the inlet (which is why charge air tubes often have a bit of oil in them.

Porcine_Aviator
Friday 2nd March 2012, 19:04
Hopefully someone will come along to a) give a better explenation and b) tell me if i'm talking gibberish!

You are dead right and yep you do talk gibberish even if it's correct gibberish. Ooops banned :)

LiamT4
Friday 2nd March 2012, 19:07
You are dead right and yep you do talk gibberish even if it's correct gibberish. Ooops banned :)

I do have a phd in talking b*ll*kcs. lol

Porcine_Aviator
Friday 2nd March 2012, 19:10
:worship::bow_kneel :worship:

antz
Friday 2nd March 2012, 19:14
so is it simply just an oil catch tank? am I able to replace it with an oil catch tank adn rebather system like for example...a rally car has?

my escort has one and it runs from the crankcase and the rocker cover o a catch tankw ith breather in?

LiamT4
Friday 2nd March 2012, 19:17
so is it simply just an oil catch tank? am I able to replace it with an oil catch tank adn rebather system like for example...a rally car has?

my escort has one and it runs from the crankcase and the rocker cover o a catch tankw ith breather in?

Yes, theres a few who have done that on here.

M-R-P
Friday 2nd March 2012, 19:25
That have done that but because its a turbo, you have to be careful. There's a pipe that draws pressure from the inlet manifold that helps the pcv work. Long story short, there's a big pipe coming off the airbox to turbo pipe, from the bit with an electrical connection. Pull that off, plumb it intoa catch tank and block off the connection on the inlet pipe.
Makes sense in my fuzzy little world any-hoo :)

antz
Friday 2nd March 2012, 20:06
well that makes good news because the standard PCV seems a bit stupid.

Although Martin,....whaaa????? haha I havent ever stripped down a T5 lump or really inspected one thats not already in bits out of the car so I dont actually know what pipes run where or what they do.

M-R-P
Friday 2nd March 2012, 20:18
Sorry dude! Basically, there's 2 ports under the inlet mani ports, they normally have the pcv catchtank attached directly to them. The tank has 2 ports on top, one is split from the inlet mani and somewhere i can't remember at the mo (I think its the vac line to the brake master cylinder) the other goes round the block to the inlet pipe, before the turbo. This is the one to attach to the additional catchtank. If you do a Google search on "volvo pcv system" you'll probably get a better explanation than I can give youwhile posting on my phone ;)

antz
Friday 2nd March 2012, 21:44
cheers fella. something to think about because the pcv system fouls my engine mounts in the 240 so Im thinking of ditching it for a seperate catchtank I can mount on the inner wing.

Volvostorm
Friday 2nd March 2012, 21:50
That have done that but because its a turbo, you have to be careful. There's a pipe that draws pressure from the inlet manifold that helps the pcv work. Long story short, there's a big pipe coming off the airbox to turbo pipe, from the bit with an electrical connection. Pull that off, plumb it intoa catch tank and block off the connection on the inlet pipe.
Makes sense in my fuzzy little world any-hoo :)

On my breather system, I'm not blocking the pipe that goes to the intake, as, I'm sure I've read somewhere it need the vacuum at idle to suck the fumes out of the engine.

The big pipe will go to a catch tank. :)