q about valve cover breather, unmetered air?

Yep.

D347643 said:

does that not make any sense? wouldnt that cause your car to run f'd up? Is there a way to have an aftermarket breather yet not have unmetered air? just wondering...

btw I have mass air in my 86 , all 92 Gt harnesses.

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Disconnect the PCV

D347643 said:

Is there a way to have an aftermarket breather yet not have unmetered air? just wondering...

Click to expand...

Yep (when I said yep before it was answering yes to your question about whether you would end up with unmetered air).

As said, one can do away with the PCV completely, running breathers instead. With a bi-directional breather, one can plug the TB to oil filler (valve cover) lines...........

Good luck.

D347643 said:

ok since i have a mass air meter wont that mess things up? anyway i can fix it?

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Yep reconnect the TB bi-directional hose, ditch the breather cap and run the PCV as it's suppossed to be run. If you sue after market VCs that have a push in oil filler use this cap:
View attachment 501923

D347643 said:

where can i get one of those breathers and why shouldnt i just ditch the pcv, its a simple disconnnect PLUS ive had more than one vac leak due to the pcv and its hose.

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You can get if from fordracingparts.com or oemfordparts.com just do a search for breather cap or oil cap and you'll see the list of them. Get part number M-6766-D302 The PCV is a very efficient system for crankcase evacuation, much more efficient than a breather since you have no road draft tube like the old school cars with breather caps had. If the PCV gives you vacuum leaks replace the PCV screen, GROMMET, and valve and PCV hoses. The hoses complete with t connector should be under $20 at ford, the screen, grommet, and valve is another $20.
Tim

Drew - this is really simple. But you have to believe what you're being told. If the manifold is under vacuum (as at idle) it's SUCKING on the crankcase through the pcv valve. When it's sucking on the crankcase, one of two things can happen.

1) If the crankcase is completely sealed to outside air, then you'll pull a vacuum on your crankcase. The crank end seals and various gaskets (like Valve cover for instance) probably won't seal perfectly, so pull enough vacuum on the crankcase for long enough (long interstate cruise) and eventually you'll probably pull some air into the crankcase via one of these other paths.

2) If the crankcase isn't sealed (you have a breather or the stock hose to the throttle body) then you have a path for air to enter the crankcase to make up the air that's being pulled out of the crankcase through the pcv valve. The stock system is designed so that the make up air has already passed through the mass air meter for obvious reasons.

Put a breather on the stock system and you allow unmetered air to enter the intake whenever vacuum is present - i.e. - you create a vacuum leak. Some vacuum leaks are worse than others -- you can have minor vacuum leaks that don't impact idle or drivability that much.

If you want the stock pcv system to work correctly then put on a new hose/valve/screen/grommet -- buy the parts from the dealer as they fit better to eliminate leaks. Then reconnect the valve cover nipple to the throttle body and get rid of the breather.

Otherwise, cap the pcv port on the manifold, block off the pcv hole in the lower intake and put two breathers on. Be prepared for the oily mess the breathers will make as they dispense a mist of oil over the top of the engine. An alternative is to run hoses (at least 1/2" dia.) from each valve cover to a remote located catch can that is vented. That will relocate the mess to the top of the catch can.

D347643 said:

where can i get one of those breathers and why shouldnt i just ditch the pcv, its a simple disconnnect PLUS ive had more than one vac leak due to the pcv and its hose.

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I ordered mine from summit. It was really cheap, i think it was $7.