Lately I've had quite a few mail order tuning issues, that turned out to be related to those dang "oil seperator" setups. I tell ya, those things cause more problems than they solve. Well anyway, I've been thinking lately about the whole situation.

Everyone has been trying to STOP the oil in the intake for years. But what if we are all wrong? I'm starting to think that the truck was DESIGNED that way. Let's take a closer look....

A normal Ford vehicle, has a PCV, usually in the valve cover, or somewhere connected to it. From the PCV, there is a hose that goes to a vacuum source, like the throttle body or intake manifold. However, on the Lightning/HD, we have an EXTRA line, tee'd into that hose.

That extra line, goes to the back of the lower intake. Now at first glance, it just looks like a regular 3/8" line, going to a regluar 3/8" fitting tapped into the intake. But if you remove the fitting and look inside, it's actually a tiny metered orifice hole inside. Where the fitting taps into the intake, the intake is cast with a small "sump" which is the low point of the intake floor, as if it was DESIGNED to pickup fluid at that point.

So let's think about how it may work. Under normal vacuum conditions, the intake draws oil up from the pass side valve cover. The oil ends up in the lower intake. Now under boost, the oil is pushed into the fitting, in which the metered orifice acts like a jet nozzle, and shoots the oil back up the tube, and back into the intake.

And what could be the point of this? How about blower rotor lubrication. This could have been a design by Ford engineers, to ensure the Eaton would last 100k miles or more. Having the rotors oil coated pretty much eliminates the chance of galling, or any kind of wear. It also keeps the rear bearings lubed. One thing I've noticed over the years, is that when I've taken off blowers that HAVE oil all over them, they usually look like new. Hardly any scratches, or missing coating. But blowers I've removed that were DRY, are usually the ones that are showing lots of wear/damage.

Now if I am correct about this being a purpose built design, there is still a flaw to it. Where does the excess oil go? In other words, they made it so the oil can get up there, but there's nothing to stop the intake of oil. The motor will continue to draw oil. That's not a big deal from a capacity standpoint, since we all do oil changes. But the lower intake will continue to get oil added to it. I'm not quite sure where they intended that to go over a long period of time.

Well anyway, it's just food for thought. I'm not trying to pitch some new oil product or anything. I hate the ones people already run. I still stand by the fix I came up with years ago. An oil breather cap, and a 7/16" ball bearing stuffed in the elbow over the PCV valve.

 

Great write up. It makes sense.

 

You bring up some interesting points Sal. The question has been posed a few times between myself and a few other L owners thinking almost the same thing you mentioned... (why would it be setup to draw in oil)... has to be for a reason...

I think your ideas are right on about the oil having a purpose. Just like you said though... and from looking at the mess it causes, where did they plan for this oil to go

 

This may have been addressed before, but I would like to hear your take on it. I have been told that the breather cap introduces unmetered air in the crankcase and I have also heard it refered to as the high performance vacuum leak. Is there any truth to these statements?

Thanks Sal!

 

Very good point!

 

Things that make you go hummm

 

Just to clearify a point Sal made.

Not all the oil get leached out and goes to the lowest spot. A significant amount of it goes into the cylinder. I dare say/speculate the majority of it winds up being injested into the cylinder.

I'm of the opinion that my truck had too much "oil in the intake". At just 6k miles (driving like your grandpa) the back side of my TB was CAKED up with not just a coating of oil. But a thick crusty build up. it looked as if a NA car had driven 125k miles and never cleaned it. It was bad..

This sent me to looking and thinking about this issue. I first contacted someone in the know (at Ford) about it. He said to check and see if the valve cover baffle was persent. Second that the PCV was operating properly. If those two are good then "everything is normal".

Me being **** about my truck... I still did'nt like it. But I also am all too familiar with Fords internal processes. I **KNOW** they would'nt "not know" that this issue is present.

My actions were to pull some of the oil out of the system and leave everything well enough alone.

IMO the REM seperator has done just that. I still have a light coating on the blower rotors and lower intake but my TB and intake elbo are bone dry.

Just my two cents from what little I know, Rich

 

now we all know what goes on in Sal
s head on those long sleepless nights

good writeup very interesting

 

Some of the 'caking ' is from the EGR and not all oil related.As for what Sal said if you can do a search about that and the explaination Sal gives.I said that over 2 years ago but everyone called me stupid!
I replaced my blower just last weekend and looked at my intercooler IT is CLEAN no black vanish or anything and the blower looked great to very lite oil film on it but no galling.And I dought anyone runns as hard as I do!!And yes I am running a 4 over on the pulley!I made a breather cap that vents under psi[crankcase,which the crankcase goes to positive psi in boost]and stays in a vacum under cruise and idle..and guess what................you do NOT have to do anything to the pcm for 'unmetered' air.
But here again I am a stupid arky that knows nothing!off my rant box now.Stan

 

Stan,
I value your methods because I know you beaa the living snot out of your truck, and it's still running great. Can you elaborate on your midified check-valve? Any pics? I have the L&S seperator and it fills up like evry 2-3 weeks on me.

Thanks.

 

I'm still lost on the "unmetered" air thing with a breather cap. I have never ran one, but don't see how it would change anything running one. Guess I will have to give it a try one of these days

 

If you look at a stock system the crankcase is 'closed' to air that has not been thru the MAF[meter]that is what those 2 big plastic tubes are for,on the v/c.when you use a breather cap ,now that air that enters the cranckcase,the air is not being pulled in past the MAF[meter]and as such is now 'unmetered'.Since you have now changed the way the air enters the crankcase.Stan

 

The reasoning I assume is, that the oil coating gives the EGR gasses something to adhere too. My TB and upper intake was litteraly dripping with oil when I took it off at 6k miles. Had about a 2-3mm thick crust to the outer 50% of each plate. (0.08" to 0.120" in "arky" measurement)

I'm now at 28k miles and it's been bone dry ever since. I'd say at most it's 1/1000 as dirty as it was back then. I just wipe the blades with a rag and it looks nearly new.

BTW: Ruslow.. you ain't "a stupid arky".

Rich

 

Yes; you are right.

What about making a breather cap with a check valve so that air(pressure) can only vent outward and not be pulled in? That would prevent the unmetered air from enter which could cause a lean condition, and allow extra pressure to vent out which would be better for the motor. Maybe a thought?

 

You'd have to periodicly clean the check valve just like a PCV.

Rich