The EV-98 will shut completely during boost, while the stock PCV will continue to bleed boost if problems arise.

 

Hmmmmmmmm? And where/how would boost get into the crankcase, except through the OEM PCV? How can it "bleed boost" if boost is present(above the PCV)?

I'm not flaming you as I honestly want to know. I have the Danny Swanson kit installed so I believe it works but I'm willing to learn differently.........

Dan

 

This explains why our pvc valve needs to flow in both directions.

The EV-98 PVC valve has been out since 1998, if it is truley used on the Cobra it must be a different set-up than the L.
Why would Ford install a different valve?


The fact that we operate a supercharged engine puts us in a very different category than any normally aspirated gasoline engine when discussing crankcase breathing. In our case, crankcase breathing MUST be allowed to circulate both in a forward AND in a reverse direction. So, how does our system work and why does oil get into the manifold?

First off...all air entering our engine is metered, and should remain so unless a fuel curve recalibration is performed to correct for any modifications such as installing a breather cap. Don't think this is a fix for the oil problem either... it isn't. It only helps due to the fact that it reduces the amount of negative pressure in the passenger side valve cover during high vacuum scenarios thereby reducing the amount of oil actually migrating through the PCV valve.

Part of this metered air, during unboosted operation, enters the crankcase through the inlet tube at the bottom of the intake tube bellows prior to the tb. This crankcase mixture is then vacuumed through the crankcase to the PCV valve and into the top of the s/c chamber where it accompanies throttle-body air to be combusted. At idle this system operates at around 18 in HG... not enough to draw oil up the PCV line to cause our problem. However, our engines like to create vacuum, especially when we suddenly get off the throttle at 4000 plus RPM. Here I have seen vacuum draw as high as 24 in HG! This is enough vacuum to suck the heavier oil droplets recklessly splashing around inside our valve cover up through the PCV valve and into the top of the charger. Long decelerations from high RPM's will build this oil volume rather quickly as some of you can see in your coalescing type oil separators. This is the major source for our "oil in the manifold".

Increasing boost, as most of us have done, increases the significance of this problem.

During most boost scenarios (not all), pressure will build at the top of the s/c causing crankcase breathing to reverse direction. As positive pressure builds at the top of the s/c, crankcase gasses are forced back down through the PCV valve, through the crankcase and out the inlet tube into the inlet air stream. This pressure, normally, is no greater than 2psi and does not have the strength or velocity to carry oil back to the bellows chamber. Again...increasing boost, above factory preset levels, and long durations of high boost, will influence this number for the worse. Even still, this avenue for oil depositing into the intake is minor compared to the frequency and volume of oil entering the manifold from the PCV valve line. The ebay kit does nothing to address the more serious aspect of this problem.

I have communicated with an engineer at Scientific Research about our problem and became aware that Ford is well informed on this matter we call "oil in the manifold". Scientific Research is the company that worked with SVT/Ford in developing the Eaton supercharger for application on the modular engine. and also the Jaguar engine. Anyway...one of the points covered and confirmed was that the crankcase must remain unpressurized during boosted and non-boosted operations. This is the reason for the PCV valve function in our engines (it flows both ways).

The PCV valve kit offered on ebay effectively stops, or greatly reduces this reverse flow causing the crankcase to pressurize. With the crankcase pressurized, even for a very short duration, damage to engine seals could result along with oil being pushed past the piston rings and into the combustion chamber. At a nominal 3000RPM this damage can happen very suddenly!

Is there a cure for this problem? I know of one and it really is not a cure in the true sense...but it works. On my Lightning engine between the valve cover and the supercharger is a small, billet aluminum centrifuge which allows engine produced vacuum, or pressure (it works both ways) to spin the crankcase oil/gas mixture, effectively separating the heavier oil droplets from the lighter gasses and isolating them. The oil is gated off and channeled to an unpressurized chamber where it is allowed to flow back to the engines oil supply..all automatically and without maintenance. This is a one of a kind unit, not for sale.

Years ago, an aviation industry engineer solved a similar problem in a similar way. He was tired of seeing the unsightly mess made by engines blowing oily crankcase gasses all over the bellies of expensive aircraft. He designed a dual stage, centrifuge/oil separator to clean these gasses before they were exhausted under the engine cowling. It worked! The captured oil was returned to the crankcase instead of dripping down the fuselage.

Those of you who own Lightnings and are aviation enthusiasts check your accessory catalogs. I believe these units are still being manufactured today.

I hope I have helped some of you understand the dynamics of our problem. As we all know, this excessive oil intake is not good for many reasons. To the best of my knowledge the compressor type filters on the PCV line are the most cost effective device available for oil separation and they seem to be rather efficient if the filtering media is
maintained and the reservoir bowls are emptied prior to being full. Thanks for listening.

 

How others have solved this problem.
http://www.autospeed.com/cms/article...les&A=0338&P=1
http://www.y8s.com/celica/air-oil/
http://www.andair.co.uk/extra/sep.htm
http://www.diesel-central.com/News/OilAirSeparator.htm
http://www.m-20turbos.com/separator_facts.htm
http://www.m-20turbos.com/breather.htm
http://www.m-20turbos.com/products1.htm
http://www.turbophile.com/turbophile...rmation.html&1

and I could keep going. Looks like a opportunity for someone to enter the aftermarket world, like Jay and Herb did with their products.

 

damn, I think Im going to pass out from all the reading. Good info

 

Interesting mod, think I'm gonna use my Oil Separator from REM and attach a hose to the bottom of the cup so it will automically drain back into the engine.

Now how will I attach the hose back to the valve cover so the system still works like stock?

 

I like that idea... As long as it will actually work.

Since my L stopped smoking on startup after installing the EV-98-B PCV valve, can I not assume that it is at least helping things?

I don't want to hurt my engine, but having it not burn oil all the time now has to be better.

I am going back to the stock PCV valve tonight - I will see if the smoke on startup resumes.

 

I get that too sometimes from what I have been told. Some of the guys at my work have seen a small amount of smoke come out when I start it up every now and then. I havent seen it yet, have to get someone to turn the key for me so I can watch. Is it anything to worry about?

 

You never ever want boost to go back into the crankcase. Skip

 

try these

http://www.roadraceengineering.com/eclengine.htm


2 products half way down. One is made by Greddy and is Polished.