Topic: Oil Catch Can vs Oil Breather Tank

[miller11386]

keep dreaming on the dry sump setup Those things run for $3k+ to start!

Also you can pretty much figure that if DDM Dave sells it, its probably the best design. Mostly being that he is a smart gearhead and wants to provide the best stuff to his customers. Its the same reason he has the good thick cores on his intercoolers vs the Chinese junk that others sell, and the reason he sells a catch cat setup rather than a breather setup. Also the reason he only builds carillo rods in his built motors.

Also if anyone needs a catch can, I have a red one for sale! .......Or it will be going on my next car lol I kinda want to make it work just to keep some of my kappa roots...

[Carbon Sky]

keep dreaming on the dry sump setup Those things run for $3k+ to start!

Also you can pretty much figure that if DDM Dave sells it, its probably the best design. Mostly being that he is a smart gearhead and wants to provide the best stuff to his customers. Its the same reason he has the good thick cores on his intercoolers vs the Chinese junk that others sell, and the reason he sells a catch cat setup rather than a breather setup. Also the reason he only builds carillo rods in his built motors.

Also if anyone needs a catch can, I have a red one for sale! .......Or it will be going on my next car lol I kinda want to make it work just to keep some of my kappa roots...

Some more excellent reading in response to differences between vacuum/pressure in the crankcase, and in the heads.  Yes they are linked through passages, but can be quite different in vac/pres.

http://www.theturboforums.com/threads/362912-How-much-is-to-much-crank-case-vacuum

Seems too much vacuum in the crank case is just as much of a problem as too little.  As for the heads, it seems the minute amount of vacuum applied doesn't do do very much (captions in the videos provided pretty much say so).  Key word he said was "maybe", and the caption clarified.

The research continues.  But it looks like preliminary information is saying yes the OCC keeps the system running more OE like, while providing benefits, while the OBT can provide the benefits but may alter OE parameters potentially causing problems.

[07 Boss]

Just posted this up on another forum yesterday.  I'm for venting to the atmosphere.  There are a couple advantages to a closed flowing pcv system with a little vacuum in there but it is far outweighed by the benefits of not running that crap back through your motor.  Here is the post from the other forum, it may help explain some of the pros and cons.  Even though it is for a different motor the principles are the same.


Blow by is the stuff that gets past your piston rings. It's either unburnt fuel or burnt exhaust gases. If it had no way to escape your crankcase it would build up enough pressure to blow out engine oil seals (or as previously mentioned, dipsticks). In the old days they just would have a couple of one way check valves and would vent that stuff through a couple of baffles right out into the engine compartment. Then the EPA cam along and said we can't do that anymore.
So along came our modern PCV system. That blow by stuff now gets sucked back into our engines to be burned in the cylinders. It does a good job of keeping the air cleaner. Now there a couple of drawbacks to this. It is dirty air and it displaces clean air which can better support the combustion of fuel. Less fuel burned, less power. It will also lower your effective octane rating which effects the amount of timing you can run.
Today's PCV system has to deal with EFI and air sensors so it cannot just suck unmetered air into the air fuel charge without consequences. It would be like a giant vacuum leak So it is run off of the vacuum from your intake manifold it has to draw air from the metered air after the MAF but before the throttle body. It also flow when there is no actual positive pressure in the crankcase. This is actually a plus. The constant flow helps remove atomized unburnt fuel out the crankcase which if it disolves in the oil, causes premature break down of your oil.
IMO the performance benefit of not running that shit back through your motor outweighs any of the pluses. Oh, another one of the draw back of our stock system is that oil/fuel mist now gets deposited into your manifold and heads and. An gunk everything up. Do a search and you can find pics of gummed up charge motion plates that folks have pulled out of their motors.
Anyways, breathers are just the old school way of venting the crankcase. Installing them is a cinch but also has it's drawbacks. The odor of the blow by can enter the cabin and may bother you. I happen to like the smell as much as an uncatted exhaust. Just smells the way cars used to when I was a kid. You can also run a hose from your cam cover to a remote mounted breather and remove the fumes from the vicinity of your cabin air filter/intake Another drawback can be some oil drips from your passenger side breather. When you install breathers the flow of blow by only escapes from your passenger side cover. Since this is a small opening it sometimes has some velocity and oil will start to soak the breather. As more oil gathers there it becomes saturated and drips. That is why you see an oil cap breather on my car. It gives the pressure another way to escape and slows the velocity and thus less oil mist collecting on the filter. This pretty much eliminated the oil drip issue. I also change the passenger breather every once in a while because it will eventually get oil soaked. You don't ever have to swap the drivers side because it really just sits there and looks pretty. The PCV or one way check valve is actually built into the inside of the cam cover. Ideally, and I will do this to my laser etched Ford Racing covers when I get them, you should dremel that thing out of there to make both breathers functional.
Now, breathers are not smog legal so they will never pass a visual inspection but will pass where it is only an OBD check. So running a catch can is an option which will reduce, but not totally, the oil mist issue gummy up your intake tract, but you are still displacing clean air with exhaust gases.
So that is the basics and the pros and cons of the different ways to deal with crankcase pressure. IMO, breathers are the best way to go, and they look old school.

[07 Boss]

Another thought that I forgot to mention.  Blow by at it's greatest when cylinder head pressure is the greatest, basically during the compression and exhaust strokes of the piston at open throttle posistions.  For boosted applications this may be an issue.  What happens when your manifold is under boost instead of vacuum and there is also positive pressure in the crankcase?  In these situations my thought is the system must flow backwards.  When there is no vacuum or equal pressure on both sides of the pcv valve it will not open, so where does the pressure from the crankcase go?  The only place it can go is out through the intake connected to our intake tube.  This causes this oil mist to enter our intake tract before the turbo, intercooler, and throttle body.  When I swapped my upper and lower intake tube last month I found quite a bit of oil gathered there.  This leads me to believe that it is already gummy up all of those parts with a sticky gooey mess.

[Carbon Sky]

Thanks for the info Boss. 

I have been essentially trying to research into these issues.  From what I've learned recently, there is this metered air issue.  I have also learned that there is a big difference between having/wanting pressure or vacuum in either the heads or the crankcase.  And that just because one is perhaps under vac or pressure doesn't mean the other section has to be the same, even though they share oil passages between them.  Which is why the guy in the video mentioned words like "slight vacuum" and "might affect oil flow, I'm not sure".

So it's starting to come down to that the OCC should maintain stock-like flow and what not through the head section (not affecting the crank case), it can and still does allow oil vapor back into the intake stream.  The alternative is the OBT which will now effectively eliminate ANY oil/blow-by whatever you want to call it.  And the true main down side might be a slightly oily film in its vicinity.  There is likely going to be zero affect to the car otherwise.

To look into this more, I intend on getting an OCC, running it as an OBT at first.  I will take vacuum/pressure measurements in the head and in the crank case before and after.  I will monitor for issues like changes in vac/pressure, volume of oil coming out when running it as an OBT versus when running it as an OCC, and just how much oil residue is coming out of the breather.

To be honest, an oily deposit is not an issue for me.  I know it is for a LOT of people, and I totally understand that, and if so, go with the OCC for sure.  But my car is a daily driver that goes through 4 seasons every year.  I have rust-proofing sprays and what not EVERYWHERE in the engine bay already.  There's CRC-SP400 and Loctite Maxi-coat on ANYTHING in my engine that is a fastener that doesn't get extremely hot, or any other exposed metal showing oxidation, which is pretty much anything not coated/painted.  So you can imagine, it ain't pretty, but also isn't going to rust.  So a little oil residue near the OBT ain't no thang to me.

I'm not a huge fan of the location DDM has chosen simply because it's near the turbo and will get HOT.  I was thinking send the line on a downward trajectory forwards, towards the right side of the structural part of the bumper.  Plus then if/when it releases residue, it will be in areas I've coated with rust proofing anyways.

Also, I have no issues with emissions testing and running an OBT.  The only visuals I must past are specifically the following:

Must have a catalytic convertor, and a gas cap.
No defects in the fuel filler pipe
Visible smoke from the tailpipe
And safety issues that would prevent an e-test (when they put it on a dyno and put a sniffer in the tail pipe)

I ran my previous car with a breather and passed e-test.  And hell, I even have to put the stock downpipe (catalytic convertor) on the car to pass the test.  So what?  My first test starts when the car is 7 years old and will need to e-test it to have it registered for it's 8th year on the road.  So I have 3+ years left till my first test (2016), and I've been driving the car 4+ years already.  It's not a big deal for me to do this 1 time after 7 whole years on the road.  So if swapping the cat, and putting the stock tune back on the car for an e-test isn't a big deal for me, even if I had to plumb this stuff back to normal wouldn't be a big deal.  And I'm not even going to, because it's not an issue in a visual check in my area.  And even if it were, I have friends that are automechanics that will help me out, which I have never had to resort to yet because I've always made the car pass when I needed it to.

But anyways, sounds like it's gonna be get an OCC, run it as an OBT, test things out before/after, and go from there.

Thanks again miller and boss!  Great info! 

[TomatoSoup]

OK, I think everyone's getting confused a bit here.  We (well, the original post, anyway) are not talking about the PCV system, hence "blow-by" has nothing to do with it, nor does (should) crank case pressure be affected.  We are talking about the TOP of the engine - i.e. valve (or cam) cover ventilation which is largely a separate system (unless you have leaky valve-guides, I guess).

As for "un-metered" air - I haven't read the long posts carefully enough to really see what's being talked about, but the only issue with this mod IMO would be if the hole in the intake, where the (removed) vent tube went, was not plugged.

[Sol Asylum]

Where to begin?

Miller claimed that you need a vacuum to reduce "oil blow by" I am still not sure what he means by that and if you actually read my post you will see I asked about that.

As for the crankcase needing metered air, the air entering the crankcase is coming from the intake per Millers video but there is nothing metering or sensing the air allowed into the crankcase.  The air is simply allowed to flow into and out of the crankcase as intake vacuum aft of the throttle plate requires.  Saying the crankcase air is metered because it uses air in the intake which is metered is inaccurate.

As for my technical knowledge and skills in the automotive world, I will put them up against you and yours anyday of the week, I have already seen your fiberglass skills and am not worried in that department.  Just because one can write a novel long post doesn't mean they truly understand and can comprehend how something works.  Watching a YouTube video doesn't prove a thing as that person may or may not know what they are talking about.  Just because it's on the internet doesn't make it fact.

The fact that you are trying to determine how much vacuum is in the crankcase in an example of lack of understanding, the vacuum amount varies based on a lot of different factors and if it really made that big of a difference then there would be a more precise system to control it but I can't say I have ever seen an engine that has such a system.

TS the top of the valve cover is technically part of the crankcase as the cam area and the crank area are all connected and not sealed separately from one another.

[elff]

It's entirely for environmental concerns, and no other (I've looked into PCV systems before).  Don't assume otherwise unless you have some information please.

I believe the above response to Critterman is where the original attitude started.
It was a little harsh considering this is all that Critter wrote

The system is designed as a closed system, so one would think there is a reason that it is closed.  Even if it only is an enviromental concern.

Critterman was trying to constructively add to the conversation. 

Moderators
Are we now allowing flat out swear insults in non Deep End threads?

[elff]

As far as the topic

We have numerous cars with OCC's installed for over a year working quite well.
I would guess the actual number of installed OCCs on kappas would easily be over 100.
DDM could probably let us know how many they alone have sold.

But
If you feel the breather works, install one and document it.  Real world testing and actual experience is always nice to have.

The theory has been discussed and at this point is at a stalemate.  If you feel the breather works and would be better, only thing left is to test it on a kappa.

Shy of that, its just talk

[DeepBlueGXP]

I cleaned up this thread.  Please keep this on topic and clean.  Post facts and if you don't have the facts, do as Elff suggests and install one and post your results.   If you want a more "flexible" discussion on the issue, take it to the deep end.  If you need access to the deep end, PM me and I'll update your profile so you can see the hidden sub forum.  http://www.kappaperformance.com/forum/index.php/board,86.0.html

[07 Boss]

This debate on breathers vs closed PCV system has gone on since the 1970's and I've found the opinions are pretty evenly split on which is better for your motor. There are pro's and cons to both and it all depends on how much weight you give to them to decide which side of the fence you are on. There is no right or wrong answer, it's more of a preference thing.
But to clear up a few things. The top and bottom of your engine are not sealed off from one another. Though there may be times that there is a difference in pressure, it is basically one cavity connected with oil drain back passages or whatever. The unmetered air that we refer to when dealing with PCV systems happens when you open up the closed system but still are trying to use the vacuum in the intake manifold to help evacuate the crankcase. If you want a sealed system then fine. But if you want to run breathers, or oil breather tanks, you have to plug the intake manifold connection. If you leave this hooked up you will draw in unmetered air. So there is no halfway. You either run a closed system where the air flow is taken from the intake tube and metered by the MAF, or completely open up the system to the atmosphere with breathers.
I chose to go with breathers because it better fits the importance of my needs. I'm one that only wants to put clean air and fuel (well maybe methanol or nitrous) into my cylinders. So the benefits of running breathers outweighed the benefits of a closed system. Others will put more weight on the advantages of using manifold vacuum to help evacuate the crankcase over the disadvantages of running that shit back through your motor. I am neither right or wrong with this decision, it just better suits my needs.

[TomatoSoup]

Sorry, just got back to this thread.  I have to agree that my statements were incorrect (thanks SA and Boss) I was forgetting that (of course) there is only one oiling system and thus the crankcase and cam areas are surely interconnected.  My bad.

Also, as I read Boss' last response and think about it, you (I think) would have to close off BOTH connections to the intake tube to avoid an 'un-metered air' issue (per Miller or SA - I forget).  If you have metered intake air being split and sent into both the combustion chambers and the cam area, then the cam area is vented to outside, then the engine isn't getting as much air into the combustion chambers as the ECM thinks and thus running rich (presumably).

(I assume this is what Boss/SA/Miller were trying to say, but that I was too lazy to read )

[elff]

Boss

Do you have pictures of your setup you could share?

[Carbon Sky]

Some preliminary test results:

With the 2 stock braided lines in place as they were from factory, measuring vacuum in the crankcase at the oil dipstick area yielded a vacuum of ~3" Hg which is significantly less than the vacuum in the intake manifold post turbo at idle.  Likely as a result of the vacuum pump and/or PCV control system PCV system on the driver side of the engine.  I then disconnected the line that runs from the intake (where the plastic nipple often breaks) at the engine side.  I put a rubber cap on the plastic nipple, and a vac gauge up to the heads on the nipple.  That yielded under 1" Hg.

I then reconnected the new rubber hose between the intake and the head (so it was just like the stock line except it didn't have the check valve in it anymore).  I then removed the lower line that goes from the head to the turbo (the line where some oil can come out, entering at the turbo, and sending oil into your intake system).  I took a vac reading there and it was ambient.

I'm guessing there is a 1 way check valve in the head somewhere that only allows it to flow outwards at this line, and not inwards as well.

Also, I disconnected some of the lines for the PCV system at the intake manifold, and it was MUCH cleaner than the line going from the head to the turbo.  There was no liquid at all in the PCV lines at the intake manifold (some minor brown residue).  And there was definitely some liquid oil coming out the line going from the head to the turbo.  Looks like the PCV system is functioning properly, while the ventilation for the heads on the passenger side is causing the oil in the intake problems.


Interesting find:

While doing this research, came across this interesting part.  It's a vented/filtered oil filler cap.



For extra breathing to the heads!

[07 Boss]

Boss

Do you have pictures of your setup you could share?

They are on my Mustang. I just got my GXP and haven't done anything to it except change the intake tube because I broke that plastic nipple for the PCV intake. I haven't reall even had a chance to clean up my engine compartment and start pokin around. But if you would like I can post up pics of my mustang engine and breather set up when I get home. I'm sure it will be something similar on my GXP.

[07 Boss]

Some preliminary test results:

With the 2 stock braided lines in place as they were from factory, measuring vacuum in the crankcase at the oil dipstick area yielded a vacuum of ~3" Hg which is significantly less than the vacuum in the intake manifold post turbo at idle.  Likely as a result of the vacuum pump and/or PCV control system PCV system on the driver side of the engine.  I then disconnected the line that runs from the intake (where the plastic nipple often breaks) at the engine side.  I put a rubber cap on the plastic nipple, and a vac gauge up to the heads on the nipple.  That yielded under 1" Hg.

I then reconnected the new rubber hose between the intake and the head (so it was just like the stock line except it didn't have the check valve in it anymore).  I then removed the lower line that goes from the head to the turbo (the line where some oil can come out, entering at the turbo, and sending oil into your intake system).  I took a vac reading there and it was ambient.

I'm guessing there is a 1 way check valve in the head somewhere that only allows it to flow outwards at this line, and not inwards as well.

Also, I disconnected some of the lines for the PCV system at the intake manifold, and it was MUCH cleaner than the line going from the head to the turbo.  There was no liquid at all in the PCV lines at the intake manifold (some minor brown residue).  And there was definitely some liquid oil coming out the line going from the head to the turbo.  Looks like the PCV system is functioning properly, while the ventilation for the heads on the passenger side is causing the oil in the intake problems.


Interesting find:

While doing this research, came across this interesting part.  It's a vented/filtered oil filler cap.



For extra breathing to the heads!

If you're going to use that oil cap breather you have to open up the whole system to the atmosphere. .

[Carbon Sky]

If you're going to use that oil cap breather you have to open up the whole system to the atmosphere. .

Very aware of that . . . posted it because I found it humorous based on all our back and forth lately.  It was actually a late model (coyote) Mustang application coincidentally.

[miller11386]

i love threads like this

[Gentleman Jack]

i love threads like this

I prefer 500 count. This one is just too scratchy.