oil separator

What car? Is it connected properly? Does your engine have an excess amount of blowby?

They're not very complicated devices.

Pictures?

 

DEFINED: Oil and Air Separator

The crankcase in a car is used as a storage place for oil, usually in a pan located below the crankshaft. While the crankshaft and the oil aren't intended to come into contact (because if they did the oil would get frothed up like a thick, black milkshake), oil vapors can still find their way into the blow-by gases. It's not a good idea for these oil vapors to be recirculated back into the cylinders along with the blow-by gases because they make the gas-air mixture too combustible, equivalent to lowering the octane of the gasoline, which in some engines can degrade performance slightly and in older engines can even cause backfire when the gas-air mixture combusts prematurely. The oil vapors can also coat the air intake with an oily film, gradually clogging the air flow over time. If you don't drive a high performance vehicle, these problems aren't exactly crucial to your car's operation and the oil build-up can be scrubbed out periodically during maintenance, but some people (and some car manufacturers) prefer to have something that will scrub the oil out of the blow-by gases before they're recirculated in the first place. Enter the oil and air separator.

The idea of an oil and air separator is to extract the oil from the air before it's sent back to the intake manifold and put it someplace where it won't cause a problem, either back in the crankcase or in a small receptacle called a catch can. Not all cars come with built-in oil separators and not all cars necessarily need them, but they can be purchased as aftermarket items. And if you have the necessary DIY skills, you can even make one yourself.

There are actually a number of different ways in which these oil and air separators can work. Probably the most common kind blows the oily air through a mesh filter. The oil droplets are trapped in the mesh while the air passes through. The most effective such filters are made up of microfibers, which can trap very small particles of oil. Alternatively, the air and oil filter may require the recycled gases to go down a tube with holes in its side. The lighter air molecules escape through the holes, while the heavier oil droplets fall all the way to the bottom, where they can be removed. And some advanced systems use a centrifuge to drive the heavier oil droplets out of the air. The oil coalesces on the sides of the centrifuge and can be channeled back into the crankcase.
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Ant:

These look very much like the ones on the Spica-injected Alfas of the 70's -- and not that much different than the thing in my old '84 GTV6. If they are the same on the inside, then there is a corrugated brass filter element and a screen inside, I think the idea is that these cause the oil vapour to condense and force the droplets to coalesce... the oil is then collected and returned to the pan/sump.

I've never opened mine up on the Ferrari... it seems to be working fine.

If I were you, I would try soaking it in some suitable solvent and blowing it out with compressed air, then allowing it to thoroughly dry. I bet it's full of residue.

I don't know of any aftermarket separators for Ferrari, but I think you could find something that fits Alfa and adapt it. In the larger aftermarket, there are many such devices, though they would not be identical in appearance or performance.

If your unit is ineffective at removing oil, I think it could certainly end up fouling the intake as you describe. I do not see this with mine.

I'll also mention that a good replacement for the associated hoses is a hose meeting the MIL-DTL-6000D specification. This type of hose is widely used in aircraft, and is available from suppliers of aircraft parts. It has a very good resistance to most automotive fluids and is reliable with hot oil vapour passing through it. (One of the qualification tests involves boiling it in fuel and then inspecting it!). It is only available in imperial sizes... I believe 0.75 inch ID is the size I used for the larger hoses in my QV. (Measure to be sure.) My hoses were all looking pretty bad, and a night of research suggested that this aircraft-grade hose would be a better replacement than anything I could find from automotive vendors.

Best luck with it, and post pictures if you end up doing an autopsy on it.

Charles

 

They get condensation in them and rust internally. The should be removed and cleaned out regularly.

 

A piston engine is a big air pump. We usually only think about what goes on in the combustion chambers on top of the pistons. There is a considerable amount of air being displaced underneath the pistons. In an ideal world, with pistons going up and down alternately, pressures should remain at equilibrium. In reality there is always a bit of leakage (blowby) that enters the crankcase from the hot side of the pistons. This excess gas/air needs to be managed. If no breather was provided, pressure would build up and eventually escape through the available paths, usually front & rear main bearings, where massive oil leaks would be the result. In the old days, the breather pipe was just left open and directed toward the ground. Today that's not acceptable and a closed system is used. Hose #2 provides a bit of vacuum to the system to maintain negative pressure. When an engine wears, blowby increases. Eventually it can exceed the capacity of the vent system to keep up, especially if it's plugged up or not connected properly.

 

Not to mention that a motor with a vacuum in the crankcase makes more power.

 

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Yes, some negative pressure.

 

There is vacuum there anytime the motor is running, not just idle.