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I would recommend that you cease your search for an original pcv and go with the M.E.Wagner.

There are several reasons why. The originals are low perf items. Literally costing a few cents each new and performing every bit of worth the money.

PCV are not supposed to leak vacuum at idle but are supposed to open at a predetermined vacuum level roughly corresponding to the car at cruising.

That's the theory but in practice rarely achieved.

Wagner's leak the least at idle. Right around 1 in of mercury. The stock ones leak somewhere around 4 or 5.

At sudden wot opening they are all supposed to close to prevent a sudden lean mixture. Wagner's do. Stock? Maybe?

Wagner's are precision made and are EASILY adjustable to deal with the specifics of your camshaft vacuum characteristics.

To those who think the right thing to do is to run open valve cover breathers? There is data available that shows that a crankcase negatively pressurized (as a correct pvc system does) adds around 25hp to the engine.

Inches of mercury and psi are equivalent. 1 in of mercury is equal to 1 psi. A maximum of -12psi crankcase pressure is recommended. More then that and you can suck in the crankshaft seals.

You normally should have 10-12 at cruising but you need an installed vacuum gauge to see that.

The reasoning is that the vacuum helps seal the compression piston rings. So if you are running open breathers you are giving away around 25 hp. That's free horsepower to be gained just by running a functioning pcv system.

I have two of the M.E.Wagner units in two of my cars. One of them running "Webers".

They are dependable, made of stainless steel and completely rebuildable if need be.

I feel that I can vouch for them and recommend one to you if you are wise enough to run a pcv system. The M.E.Wagner would be a smart solution.

Last edited by panteradoug

My "guess" is no.  The PCV valve "sucks" stuff out of the crank case - as Doug described.

To have enough pressure in there to pop the dipstick, while (also) blowing through the PCV valve would seem to me to be a pretty significant pressurization.

Have you run the engine with the PCV Valve removed (or breather, or the oil fill cap) and put your hand over the hole, and checked to see if you feel a lot of pressure blowing out of the case when the engine is running?

If you have enough "blowby" (it would be from compustion pressure - rings) to pop the dipstick out of it’s seat, you should see other effects, like oil inside the air cleaner (if you have a breather going there).  I would also think you would see oil vapor coming out of the dipstick tube once it is popped off.

Certainly your PCV valve ought to show symptoms of oily flow back into the manifold.

Let us know.


Last edited by rocky

Your issue is being caused by a non-functioning pcv.

If you are blowing out the dipstick, you have piston rings leaking compression and you are going to blow out the crank seals also.

You can confirm this with a leak down test.

IF you have recently done new piston rings then that would not be too unusual. It takes a few hundred miles of cruising for the rings to completely seal BUT they need help of a negative pressure in the crankcase to help them seat and stay seated.

In the leak down test, you will actually hear them leaking compression.

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