Air out the Cap

[frapjap]

A friend of mine has an SR that when you take off the oil cap while running, you get a...much more than usual amount of air flowing out of it. Is this prominetly from bad seals, or is there something bigger at hand here?

[Axel Grungy]

why are you taking off the oil cap when its running??

[frapjap]

Couldn't tell you. He diescovered it, asked me to post it. He doesn't run without it, just took it off at idle for X reason. Haven't seen the thing myself. Someone called it postion blow by.

[fatboy]

does he have a pcv valve intact? check that first.

[frapjap]

He mentioned that but when asked what it was/did he couldn't respond with a very good answer, so I let it go. What is it and its function?

[Red coupe]

pcv= positive crankcase ventalator. IT lets pressure out of the crank case. Piston rins cannot seal %100, some pressure wil always seep by into the crank case, if the case was seeled it would pressurize till the unburned air/fule mixture ignited from heat. originaly a vent was added that vented through a filter to catch oil and released preture to the outside air. However the whole emitions thing came around and so a valve was added to alllow venting of the crankcase back into the intake so unburned fuel could be reused to keep emitions down.

[frapjap]

Nice, thanks for the lesson. Ya learn something new everyday.