So...what's the final word on this subject? Is there a final and optimal solution? I've read that some people get the rear window all greasy due to the oil mist if you place a filter back there, some smell the fumes in the cabin etc. I think I even read that someone meant it's not good for the engine because you need the vacuum created in the intake pipe to suck out all the oil/fumes efficiently.
The hose between the IC and the inlet manifold had quite a lot oil in it so I would like to avoid that if possible.
IMO the best solution for the engine is to vent the positive pressure gas from the crank case and/or cam case to a largish separator and then vent the exit of the separator to atmosphere. This will stop oil and zero oxygen air going back into your inlet track which would both reduce power (due to lower oxygen content) and spray oil on your pistons and valves which leads to carbon and fouling your IC matrix.
However venting oily gas to atmosphere has a few drawbacks:
1. Contrary to Euro4 (which your strict MOT might pick up).
2. Potentially slightly smelly.
3. Oily residue where-ever it ejects and perhaps a thin oily film over the back of your car that attracts dirt.
IMO the best solution for the engine is to vent the positive pressure gas from the crank case and/or cam case to a largish separator and then vent the exit of the separator to atmosphere. This will stop oil and zero oxygen air going back into your inlet track which would both reduce power (due to lower oxygen content) and spray oil on your pistons and valves which leads to carbon and fouling your IC matrix.
However venting oily gas to atmosphere has a few drawbacks:
1. Contrary to Euro4 (which your strict MOT might pick up).
2. Potentially slightly smelly.
3. Oily residue where-ever it ejects and perhaps a thin oily film over the back of your car that attracts dirt.
Thanks Nev. I have noticed that many of the VXR owners add this breather box from the Omega and other models:
And place it between the crank case outlet and the cam cover:
What about adding that one too and let it take care of the major part of the oil, and then have another separator after the cam cover, just like you described? Twice as good or redundant?
IMO the best solution for the engine is to vent the positive pressure gas from the crank case and/or cam case to a largish separator and then vent the exit of the separator to atmosphere. This will stop oil and zero oxygen air going back into your inlet track which would both reduce power (due to lower oxygen content) and spray oil on your pistons and valves which leads to carbon and fouling your IC matrix.
However venting oily gas to atmosphere has a few drawbacks:
1. Contrary to Euro4 (which your strict MOT might pick up).
2. Potentially slightly smelly.
3. Oily residue where-ever it ejects and perhaps a thin oily film over the back of your car that attracts dirt.
Thanks Nev. I have noticed that many of the VXR owners add this breather box from the Omega and other models:
And place it between the crank case outlet and the cam cover:
What about adding that one too and let it take care of the major part of the oil, and then have another separator after the cam cover, just like you described? Twice as good or redundant?
That thing can only help I expect, though I've no idea of it's internal design, presumably it is baffled and has some spongy "collector" material stuffed in it.
Remember that the outlet from the cam cover is the best place to take fumes away, as the underside of the cam cover has a series of galleries and channels that are specifically designed to get as much oil out of the vapour as possible. However, the cam cover pipe is only 9/16 diameter (if I remember correctly) , so on an engine that breaths heavily (I don't know if yours does) then this isn't sufficiently large enough.
On my car when it was breathing heavily I took 1 feed from the crank case and 1 feed from the cam case, each into their own separator. Now that it is run in better I only take a feed from the crank case as this is the primary source of positive pressure and have blocked off the cam cover exit.
This is a video of my old engine that was breathing far too much. I decided to rebore + hone it in the end, as the ring blow-by was too much. Oil consumption on it was about 0.5 Litres every 150 miles when driven hard and quite a few motorbikes got a "black cloud" shock when behind me!
I don't see why the Z20LET solution needs to be any different to the options investigated for supercharged Z22SE. The simple fact is that blow by ventilation scales with engine power so both systems become overwhelmed as power increases. The best option I have found is the Mann Hummel Provent series (I'm running the provent 200). The benefit of this system is that it drains back into the sump, which makes it a much lower maintenance part than a simple catch can.
Many heavy duty engines are fitted with similar devices, see video;
I don't see why the Z20LET solution needs to be any different to the options investigated for supercharged Z22SE. The simple fact is that blow by ventilation scales with engine power so both systems become overwhelmed as power increases. The best option I have found is the Mann Hummel Provent series (I'm running the provent 200). The benefit of this system is that it drains back into the sump, which makes it a much lower maintenance part than a simple catch can.
Many heavy duty engines are fitted with similar devices, see video;
I have to say that looks good value for the money. If I'd known about it I wouldn't have made my own.
I have been thinking about that Provent for a while as my 2.2SC does smell a little oily. Using a catch can now and venting to atmosphere. But where do you mount it? it's not exactly a small device (say about 220 x 150 mm). And what do you do with the oil it catches, does it go into a catch can or back into the engine?
IMO the best solution for the engine is to vent the positive pressure gas from the crank case and/or cam case to a largish separator and then vent the exit of the separator to atmosphere. This will stop oil and zero oxygen air going back into your inlet track which would both reduce power (due to lower oxygen content) and spray oil on your pistons and valves which leads to carbon and fouling your IC matrix.
However venting oily gas to atmosphere has a few drawbacks:
1. Contrary to Euro4 (which your strict MOT might pick up).
2. Potentially slightly smelly.
3. Oily residue where-ever it ejects and perhaps a thin oily film over the back of your car that attracts dirt.
Thanks Nev. I have noticed that many of the VXR owners add this breather box from the Omega and other models:
And place it between the crank case outlet and the cam cover:
What about adding that one too and let it take care of the major part of the oil, and then have another separator after the cam cover, just like you described? Twice as good or redundant?
That thing can only help I expect, though I've no idea of it's internal design, presumably it is baffled and has some spongy "collector" material stuffed in it.
Remember that the outlet from the cam cover is the best place to take fumes away, as the underside of the cam cover has a series of galleries and channels that are specifically designed to get as much oil out of the vapour as possible. However, the cam cover pipe is only 9/16 diameter (if I remember correctly) , so on an engine that breaths heavily (I don't know if yours does) then this isn't sufficiently large enough.
On my car when it was breathing heavily I took 1 feed from the crank case and 1 feed from the cam case, each into their own separator. Now that it is run in better I only take a feed from the crank case as this is the primary source of positive pressure and have blocked off the cam cover exit.
This is a video of my old engine that was breathing far too much. I decided to rebore + hone it in the end, as the ring blow-by was too much. Oil consumption on it was about 0.5 Litres every 150 miles when driven hard and quite a few motorbikes got a "black cloud" shock when behind me!
HTH.
Why is there the small outlet from the cam cover and not only the large one? It's on the boosted side, don't know if that makes a difference.
If it should be done properly I assume the small diameter pipe should also be connected to a separator/catch tank. Perhaps with a T-connection with the large vent hose.
I don't know how heavily my engine breaths. It doesn't consume much oil though, despite frequent track day use.
I have been thinking about that Provent for a while as my 2.2SC does smell a little oily. Using a catch can now and venting to atmosphere. But where do you mount it? it's not exactly a small device (say about 220 x 150 mm). And what do you do with the oil it catches, does it go into a catch can or back into the engine?
If you can manage the swarf with a magnet (or just take the sump pan off), you could drill and tap a drain plug nozzle into the block that the drain could feed to. If you put a 1 way valve on the pipe that led down from the catch tank to the drain plug then you'd not get blow back and it could drain when the engine is idling.
I don't see why the Z20LET solution needs to be any different to the options investigated for supercharged Z22SE. The simple fact is that blow by ventilation scales with engine power so both systems become overwhelmed as power increases. The best option I have found is the Mann Hummel Provent series (I'm running the provent 200). The benefit of this system is that it drains back into the sump, which makes it a much lower maintenance part than a simple catch can.
Many heavy duty engines are fitted with similar devices, see video; https://www.youtube....v=FrvciHy2wD8
That looks really neat! I wonder where is a good location to let the oil back to the engine though?
I have been thinking about that Provent for a while as my 2.2SC does smell a little oily. Using a catch can now and venting to atmosphere. But where do you mount it? it's not exactly a small device (say about 220 x 150 mm). And what do you do with the oil it catches, does it go into a catch can or back into the engine?
If you can manage the swarf with a magnet (or just take the sump pan off), you could drill and tap a drain plug nozzle into the block that the drain could feed to. If you put a 1 way valve on the pipe that led down from the catch tank to the drain plug then you'd not get blow back and it could drain when the engine is idling.
The check valve is actually a part of the Provent installation instructions, as is a minimum column height of 350 mm between the oil outlet and the crankcase inlet. My concern was more along the lines of do you really want that oil back in the crankcase or is there nothing wrong with it.
I don't see why the Z20LET solution needs to be any different to the options investigated for supercharged Z22SE. The simple fact is that blow by ventilation scales with engine power so both systems become overwhelmed as power increases. The best option I have found is the Mann Hummel Provent series (I'm running the provent 200). The benefit of this system is that it drains back into the sump, which makes it a much lower maintenance part than a simple catch can.
Many heavy duty engines are fitted with similar devices, see video; https://www.youtube.com/watch?v=FrvciHy2wD8
That looks really neat! I wonder where is a good location to let the oil back to the engine though?
I have been thinking about that Provent for a while as my 2.2SC does smell a little oily. Using a catch can now and venting to atmosphere. But where do you mount it? it's not exactly a small device (say about 220 x 150 mm). And what do you do with the oil it catches, does it go into a catch can or back into the engine?
As for returning the oil, at the moment it goes to a pipe with a tap. When I get a chance over winter I will be removing the turbo return bung on my B207 and adding a return line. I have also seen brazed T junctions added to the dip stick tube.
Thanks Nev. I have noticed that many of the VXR owners add this breather box from the Omega and other models:
I had one of those fitted under warranty by the main dealer, it did stop the oil issues and dipstick popping out.
That was a brand new car, obviously it was many years ago - the cast iron blocks are quite old these days
OK The dipstick popping out...does it mean the pressure in the sump was too high and this breather box somehow lowered the pressure? Maybe preventing hoses later in the system clogging up due to oil residue?
The dipstick popping out...does it mean the pressure in the sump was too high and this breather box somehow lowered the pressure? Maybe preventing hoses later in the system clogging up due to oil residue?
