Noob as question about engine components.

[Eskimo_firefighter]

Hi there, just curious about what this pipe is for?

[beeza]

When ya get a build up of pressure in the head from high rpm,it needs to go somewhere and that somewhere is out that hose and into the intake arm and back through the engine.It's set up this way for emissions because in that air is oil aswell,just small amounts.

It's popular to run a small air filter off the valve cover side but I was told by someone who knows engines:

'If ya want ya engine to last re-connect the breather hose'.


Am I right or wrong guys?

[markismaximus]

pretty much yes. But its crank case pressure not pressure in the head. Some blurb I found:

During normal compression stroke, a small amount of gases in the combustion chamber escapes past the piston. Approximately 70% of these "blowby" gases are unburned fuel that can dilute and contaminate the engine oil. At higher engine speeds (rpm), blowby gases increase crankcase pressure that can cause oil leakage form sealed engine surfaces.

The purpose of the positive crankcase ventilation system is to remove these harmful gases from the crankcase before damage occurs and combine them with the engines normal incoming air/fuel charge...

[trism]

^^ this is correct.

It feeds into the intake pipe for emissions reasons. All the nasties get burnt off in the combustion chamber.

[Eskimo_firefighter]

Thanks for that guys, really helpful stuff. So would all the aftermarket air intake system like injen, fujita come with an extended pipe to connect it to that valve, correct?

[trism]

depends really.

some come with a nipple on teh intake pipe for you to run a pipe to, others will not.

sometimes you will see them with a little filter liek this on them

http://www.enjukuracing.com/images/knbreather58ths_full.jpg

other times you will see a catch can

basically, a pipe is run from the rocker cover to a metal catch can, oil deposits will be left in it, then either a filter to vent to atmosphere, or running back to the intake pipe

http://www.gassavers.org/files/gassavers/pvc_catchcan0.jpg

[cristian]

those little air filters have been known to be classified as a defect though, under the same rule as blow off valves which aren't plumb back into the exhaust...something about all fumes released into the atmosphere must exit via the exhaust...

i know that 9 out of 10 people don't have a plumb back bov but a really anal officer at a defect station won't let you get away with it...

but like mentioned, aftermarket intakes made by reputable brands provide the inserts for this very reason...

[beeza]

Yeah that was the small filter I ran for a year or so until I was told the above.

Great one Markis!!

[beeza]

I reckon this is the best/safest set up.

Safe because of what I was told above and the popo,best because ya catching all that 'blow back' from the PCV in the oil catch can.

http://i99.photobucket.com/albums/l287/beeza2/100_2411-1.jpg

Yellow = 'If ya want ya engine to last re-connect the breather hose'.From valve cover to intake.The very very small amount of oil in the upper engine can be cleaned out with suburu upper engine cleaner,every 2nd oil change,should do it anyways!

Red = From PCV to oil catch can.'Blow back' is caught in the catch can.

note: PCV valve,where the hose connects,is on the back of the block,under the intake maniflod (fun to get to)

Green = From Oil catch can to Intake manifold.No oil will go into the intake manifold.