PCV for low vacuum camshafts?

[afret]

The system is sealed to try and get a bit of vacuum in the crankcase which is a good thing.  Don't know for sure about oil getting on the sensor but it's hard to imagine that happening if it's upstream of the evac tube.

[Heo]

Volvo used a similar system for the air injection
in the exhaust ports instead of using an airpump
A tube to each exhaust port routed to one single
checkvalve.It creates quite good vacum

[Qikbbstang]

Looking at the picture "linked" and put in below. The Moroso Separator appears to be void of even the most elementry characteristics of a proper separator. Little or no centrifugal action, no baffles, improper path/materials/pore sizes for a coalescence to occur and limited void or calm plenum space for separation/storage of the captured fluid.
   It looks like a simple wall divides the In/Out flow, forcing it down and back up in a "U" path  over a very small reservoir.  Flowing the mist/air through centrifugal action and specific stepped pore sizes encourages the fine droplets to bind together and coalesce to be captured.  Realistically a typical compressed in line air filter housing would be a far better vessel to start on this job.

http://www.moroso.com/catalog/categorydisplay.asp?catcode=18549

[drdano]

Valid points from our resident filtration expert!  Compressor oil/air separators are super easy to come by locally and should flow more than enough air to keep up.  What should you look for when selecting one? 

[Qikbbstang]

Do a little homework and get that tubing or line to be in a position to develop a vacuum. You want to have the flowing exhaust stream going around the tube so that it has a venturi effect on the end of the tube.  It would be a good idea to rev the motor and see what you develop on the end of the hose before it's even connected to the breathers.

[lovehamr]

The Moroso Separator appears to be void of even the most elementry characteristics of a proper separator. Little or no centrifugal action, no baffles, improper path/materials/pore sizes for a coalescence to occur and limited void or calm plenum space for separation/storage of the captured fluid.
   It looks like a simple wall divides the In/Out flow, forcing it down and back up in a "U" path  over a very small reservoir.  Flowing the mist/air through centrifugal action and specific stepped pore sizes encourages the fine droplets to bind together and coalesce to be captured.  Realistically a typical compressed in line air filter housing would be a far better vessel to start on this job.

All I can say is that it works and works well.  There are others in use mostly by the import crowd which would fit your definition better.  Don't forget there is a big difference between separating air and oil vs. air and water as well.

As far as the compressed air filter goes, most are plastic which I doubt would do well for long in a high heat environment, plus it would look smashing in most engine compartments. 
 
Steve

[Qikbbstang]

No doubt it works but as I mentioned it's missing the basic concepts of separation which incidentally are almost universal in separating Oil/Water, Water from compressed air, Oil from compressed air, water from oil, water from jet fuel/turbine oil, diesel oil etc etc.  I'm just saying if oil mist in a car motor can cause detonation then that crude separator is not capable of separating oil droplets from a gas stream with any efficiency and may likely in fact make shot gun blasts of oil droplets at times.
 BTW those clear plastic bowls are typically Polycarbonate - known for being........ shall I say bullitproof? .  I agree the Ind Filters are kind of ugly but then again the Mfgs make them out of SS, polished alum etc but they all have hefty pressure ratings that add weight. It's the principles of separation/coalescing that should be heeded.

[amdscooter]

What are you using to allow fresh air into the system?  My exhaust is 2.5" to 3" xpipe to 2.5x24" open steel pack mufflers, so pretty free flowing.  If I put the evac connections downstream of my O2 sensor bung, would I have to worry about any oil traveling upstream to it via reversion?

Got pulled here from the new thread same topic: http://fepower.net/simplemachinesforum/index.php?topic=687.0 and I'm not quite understanding the response to the above question.

The system is sealed to try and get a bit of vacuum in the crankcase which is a good thing.  Don't know for sure about oil getting on the sensor but it's hard to imagine that happening if it's upstream of the evac tube.

Correct me if I am wrong here. But a slight vac yes... but if there is no fresh air breather somewhere (usually on a valve cover no?) isn't the vacuum created going to be pulling air through your seals? 

 

[e philpott]

because the engine blow-by is what gets pulled into the header collector not fresh air , it never was about fresh air  .... I've been running one of those e-vac sets like afrets picts since mid late 90's and no problems , you do occaisonlly have to replace the check valves .... I run my evac with 3 inch pipes with Flowmaster 70 series mufflers (probably the most restrictive flowmaster made) with no problems

[amdscooter]

because the engine blow-by is what gets pulled into the header collector not fresh air , it never was about fresh air  .... I've been running one of those e-vac sets like afrets picts since mid late 90's and no problems , you do occaisonlly have to replace the check valves .... I run my evac with 3 inch pipes with Flowmaster 70 series mufflers (probably the most restrictive flowmaster made) with no problems

I might not be stating the question correctly so please bear with me here. I understand it's not about fresh air. But without a breather on the valve cover to actually get the air moving through the case... it's gotta be sucking fresh air from somewhere. If the block was entirely air tight it'd be like putting the nozzle from your shop vac on the palm of your hand... no draw. The only other place I can imagine it's pulling air from to get flow is past the seals.

[e philpott]

the pan evac check valve in the header collector will supply the vaccum to pull it out

[amdscooter]

the pan evac check valve in the header collector will supply the vaccum to pull it out

I get that the vaccum is created by the exhaust gasses passing past the front of the check valve orifice on the header collector. My question is where does the flow originate? Ever apply a vaccum to a bell jar for an experiment? Once the air is evacuated from the chamber to the point of the strength of your vaccum source/pump, nothing moves. You cannot pull anything out without flow though the crank case. Where is the flow coming from? Minus a breather on top of one of the valve covers I'd guess past the front or rear main.

[drdano]

Blow-by is part of the origin air that e philpott is talking about.  That air is coming in through the intake with the fuel mix into the cylinder.  When the big-bang occurs, part of it squeezes past the piston rings and into the crankcase.  The distributor hole would be another entry point, which may not be a bad thing to keep oil from weeping up past it. 

[amdscooter]

Blow-by is part of the origin air that e philpott is talking about.  That air is coming in through the intake with the fuel mix into the cylinder.  When the big-bang occurs, part of it squeezes past the piston rings and into the crankcase.  The distributor hole would be another entry point, which may not be a bad thing to keep oil from weeping up past it.

Right. But I cannot imagine blow by allows for that much movement considering the volume of air in the crank case. Surely not enough to evacuate the suspended blow by. I do believe the vaccum provided by collector venturi would be more than sufficient to evacuate the chamber as the amount of vaccum rises and falls with the engine rpm. But it's gotta be pulling air from somewhere or IMHO there simply would not be enough flow from the case to keep it from filling. Or...  I could be dead wrong. Which is why I'm asking. 

[Chad D]

the pan evac check valve in the header collector will supply the vaccum to pull it out

I get that the vaccum is created by the exhaust gasses passing past the front of the check valve orifice on the header collector. My question is where does the flow originate? Ever apply a vaccum to a bell jar for an experiment? Once the air is evacuated from the chamber to the point of the strength of your vaccum source/pump, nothing moves. You cannot pull anything out without flow though the crank case. Where is the flow coming from? Minus a breather on top of one of the valve covers I'd guess past the front or rear main.

Unless there is considerable blowby, there should be very little flow, even at greater depression.  It would be prudent to use a limiter to keep crankcase pressure from getting excessively low and causing oil starvation or seal integrity issues.  Now I'm curious to know how much vacuum can be seen at the port... and how to calculate proper orifice size.