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The PCV stands for positive crankcase ventilation. It is a one way valve that vents the oil vapors out of the cylinder head from under the valve cover and into the intake manifold, where it can be then burned off in the combustion chamber. The valve makes sure that the intake manifold could never blow back into the valve cover, if something were to go wrong, like a back fire or if for some reason there was more pressure within the intake manifold than the cylinder head/crankcase....
I know what pcv stands for. What I was unsure about was the apparently massive vacuum under the valve cover. After a run on the local dyno we heard a squeaking noise from that area and when we unscrewed the oil cap (no, not the 710 cap) the air rushed in at a great rate of knots. A bit of vacuum is OK, but this much? Haven't measured the vacuum as I don't have an appropriate gauge, but it was a lot. And yes, it didn't make sense for the inline check valve to operate the other way round - but neither does all that vacuum. I also have an unidentified oil leak in the same area, and just maybe the vacuum is sucking in a gasket or two. Just a thought. It's not the VTEC seal - I replaced that some time ago for no good result. And yes, I do know that the two are not related. Maybe the cam seal is, though, and I suppose that's the next trip.
Okay after you adding some details, I understand a bit more of your question....
So the engine should have two air ventilation ports, correct? One for the block (breather box?) to pcv to the intake manifold and one going from the valve cover to the air intake tube right?
Under normal operating conditions what you described, shouldn't be possible... I would insure that there are no kinks or blockage in either of those two vents or the PCV itself. The air should be able to flow freely from the air intake tube, to the valve cover and then from the block (crankcase/breather box) to the pcv and into the intake manifold. If air is unable to freely enter the valve cover, but the pcv is applying vacuum to the crankcase, you might be building vacuum in the valve cover as you described...
Here's a pic of the motor. Note the PCV connection, which is how the motor came to me from the UK. It's in a 1977 Mini Clubman and is not easy to see behind. Motor is a 1993 B16A2. Just one valve cover breather. There is a black tin box behind the motor, low down. What pipes/valves should connect the box to where?
The hose on the back of the IM is supposed to go to the brake booster in a civic, also that as stated above appears to be a check valve, which goes between the IM and the brake booster.
the hose on the front of the IM should go to the PCV valve and then to the black box.
The hose off the Valve cover typically connects to the Intake Arm pipe, but a lot of guys run a breather with aftermarket Intakes
Have any of you guys ever swapped a stock GSR intake manifold with a Skunk2 (ITR replica) intake manifold? If so, how did you reroute all of your vacuum lines? I'm burning oil in my Integra now that I have GSR swapped it. Not sure if it is because of bad piston rings or I have my crankcase ventilation wrong...
OK, this is how I see it. The small hose from the front of the IM goes down to the black box via a fitting near the head. The hose on the back of the IM should (?) go to a brake booster, which I don't have (the Mini has 9" brakes and needs no assistance), and I can blank it off. The valve cover can be vented to atmosphere via a small breather as I don't have a standard inlet tract - OR - I can install a small pipe to the aftermarket inlet tract and connect a hose from there to the valve cover. As I'm getting the car licensed soon, I guess that Plan B will be what the traffic people will want. And that pipe with the check valve in it can go into my growing cabinet of spare parts not needed just now.
Tell me if there's a problem with any of that.
11-07-2017, 05:05 AM
Re: B16a2 PCV query
