Pcv ??

grassy said

OK. I am a bit confused between the two items...a pvc and a breather.

Neither of my valve covers have a hole for either.

I do have a breather - part # p4120446.

Should I buy 2 pvc and put one on each valve cover or one pvc and one breather ?

Neither of my brit cars had either though one had a stink pipe which came off the valve cover and was run under the car..maybe an early pvc valve :)

Thanks


Ian.

Click to expand...

The breather is there, because manifold vacuum dissappears as the throttle is opened and at some point the blowby exceeds what the pcv can handle, so the breather allows the excess blow-by to be vented, usually to the air-cleaner,, or in some cases just vent to the engine compartment or to a "stink tube", called a 'road-vent' tube.

No vent, with only pcv, would likely cause seal leaks, or oil pushing out the dipstick tube, because of excess crankase pressure at high rpm..