Breather system and oil consumption

[prophiseer]

Well, some amount of oil is not only normal, it's inevitable. The breather line itself will also pull a very small amount . . . much less than the PCV system, though, as the breather is operating more on a venturi effect than on vacuum.

The more vacuum a motor is pulling though, the greater the quantity of oil that will be pulled through the vacuum system. Even more-so if everything is nice and clean, too (no gummy carbon buildup to absorb any amounts of oil).

TBH, considering the effects the oil residue has on the intake system - I'm really surprised manufacturers haven't started coming up with some kind of seperator system for the vehicles from the factory. Especially with the slew of drive-by-wire vehicles, and how detrimental that oil buildup is to the TB and the electronic motors that operate it. I can't count the number of GM and Ford DBW setups that have come in cause than ran like crap, and simply cleaning the TB and reseting the KAM gets everything back to normal.

[Skeith]

What about a small cylinder in line with the breather tube alligned verticaly with a screen mesh to collect oil dropletts. this would reduce or prevent the oil from being pulled into the intake. It would theoretically act as an oil seperator and allow the oil to be pulled back into the rocker cap by gravity or negative pressure when the PCV draws the crank case emmisions.

this is just theoretical of course works in smaller scale and even higher pressures such as refridgeration systems to seperate the compressor oil from the refridgerant. Hell maybe going to a wreaker and snagging an oil seperator off an old AC system cleaning it out and retrofitting it would work.

Not sure how much vacuum we're talking about here, but it may work.

EDIT: whoops, i see now your pulling 28 inches, thats a bit high. (for some reson the forum wouldent let me see page 3 untill i posted, thought it was some sort of a glitch :shrug
damn, and im having trouble getting my engine to pull 16 inches, slowly ironing things out.

I see a small puddle of oil at the base of my TB and thought it was normal as well, even research on the PCV system online stated that it was a common occurance and one of the reasons the TB and plenium get so gummed up. But i guess the question is how much is too much?

[prophiseer]

Well, like I mentioned in the OP - this motor isn't stock . . . and I have a tendancy to build a tight motor . . .

. . . but 28" shocked me a little bit as well. I would've figured no more than 22" or 24" . . . as it stands, I'm surprised the MAP hasn't kicked a code.

[geldartb]

28" at idle is a lot. I didn't think that was even possible.

that's kind of what i was thinking. i think with the stock engine mine hung around 17-20 although it's been awhile since it was stock.

[SappySE107]

28" at idle is a lot. I didn't think that was even possible.

[prophiseer]

After researching some prices . . . my cheap self decided it'd be more cost effective to make one. So, I've gathered my materials, and now have a project for this weekend. I'll prob take pics along the way and post them.

On a related note - out of curiosity, I threw a vacuum gauge on the motor earlier this week just to see how hard it's pulling . . . warmed up and at idle, the motor is puling 28 in. Damn! So that probably explains the occasional stumble right off of idle, and the slight surging when cruising at lower RPM speeds (i.e. 25-45 MPH @ ~1500RPM) - engine vacuum is right at the MAP's maximum range. Anyone know of a GM 3-wire MAP that's capable of registering above 30 in of vacuum?

[AaronGTR]

I've noticed some issues like this myself on my car. Hard starts and sometimes a puff of white smoke out the exhaust when the engine is cold, but goes away almost immediately. Get some weird stumbles and surges at idle though until the car is warmed up. Both my NB and WB O2 sensors seem to be getting fouled fast though, possibly a combination of higher than stock WOT AFR's and burning some oil? I was down about 1/4 of a quart the other day, almost exactly 1000 miles since my last oil change.

I actually have a catch can in my PCV line, but it never seems to have any oil in it so I don't think it's working. It was a cheapo can from NRG and didn't have any divider or filter material inside like they are supposed to have. I tried adding a small breather filter inside the can on the suction outlet, the theory being that it might slow down the air flow a bit and knock the oil out of suspension in the air, but it doesn't seem to be working. I was thinking of trying a different brand catch can, or maybe trying an air/oil/water filter like they used to dry compressed air and see what that does. I'd rather drain that occasionally than have to add another system to the car or keep burning oil.

of course, I'm not 100% sure that's where the oil consumption is coming from though. Could also be valve seals or guides wearing out maybe? Or piston rings? Not sure. My other car is down getting the A/C fixed right now, but as soon as it's back on the road I'm planning on putting the grand am in the garage and doing some work on it. Going to check the plugs, do a compression/leak down test, etc.... never done that on this car so I'm curious what shape the rings are in.

[geldartb]

Oh yes a vac pump is ideal, but I would think that's much more involved, and is also bumping it to the next level of pulling a high vac on your crankcase, vs just evacuating it of contaminates and crap... it then uses power, or a belt to work. This way your not tasking your alternator, or an acc belt, its just pulling from the exhaust flow.

I look at those things more like a poor mans vac pump, it doesn't pull so much to where the power increase is greatly noticed, but it will pull something and get the crap out, and not suck it right back into the intake.

figure even with 2 of either of the kits you posted your only up to $40ish and down the road you could add a pump if you want. if i get around to it this year i may give it a try, or there is always next year. already got a few extra sets of valve covers to screw around with.

one of those links from the google search said something about a pump from a cadilac.

[3400-95-Modified]

there were a few of the setups in the links i found that used pumps.

Oh yes a vac pump is ideal, but I would think that's much more involved, and is also bumping it to the next level of pulling a high vac on your crankcase, vs just evacuating it of contaminates and crap... it then uses power, or a belt to work. This way your not tasking your alternator, or an acc belt, its just pulling from the exhaust flow.

I look at those things more like a poor mans vac pump, it doesn't pull so much to where the power increase is greatly noticed, but it will pull something and get the crap out, and not suck it right back into the intake.

[Azrael]

I plan on giving the TB a good look over the weekend. It's an old 62mm FDP TB which I've had problems with the throttle stop screw coming loose before. Thanks for the numbers.

[geldartb]

there were a few of the setups in the links i found that used pumps.

probably wouldn't be too bad to run one from each valve cover like the links you posted above. might try that next year.

[3400-95-Modified]

Yeah you can run one or two of them I guess... I've seen dual setups on the Modified's at thompson. You would have to seal the rest of the motor so it actually has the ability to pull a VAC though... In other words, Plug the front PCV hole very good.

Azrael, sounds like there is something going on with your setup there... Did you check the TB to be sure its not open too far? Whats your TPS voltage at idle? I found that 0.6 is a good reading for that, and also 30-40 IAC counts at idle is a good place to be.

[geldartb]

I think he meant to put a breather on the rear valve cover vent, which is connected to the Intake PRE TB... so in theory there is no vac on that line ever... As noted the only time I can think of where it would contain a VAC would be when you go WOT and you have a slightly dirty air filter.

If you want to eliminate that pulling oil into the intake then just replace it with a tube going from your valve cover to one of these...

http://www.speedwaymotors.com/Dynatech-02-Pan-E-Vac-Kit,42754.html

http://www.shop.speedunlimited.com/p-5779-vibrant-11189-crankcase-evacuation-kit-weld-in-steel.aspx

I think you could replace the whole PCV system with this type of setup, but I'm not sure how they would work on our motors, since no one has tested something like this before. I'm half tempted to this year though.

so basically from what i found you install the long piece downstream in the exhaust pipe and hook it up to the rear valve cover and then get rid of all the other pcv stuff. right or am i wrong.
this is the search i got the info from

http://www.google.com/search?client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&channel=s&hl=en&source=hp&q=how+to+install+E-VAC+kit&btnG=Google+Search

[Azrael]

I have a similar rough idle after installing new cyl heads and manifolds. Gets worse as the engine warms up. I suspect a vacuum leak though as the RPM is always above what the PCM commands and the IAC is reported as fully cosed. That or a high mileage timing set having been introduced to stronger valvesprings.

I also always find a small puddle of oil behind my TB. Oil consumption has never been an issue though so I assumed it was normal.

[3400-95-Modified]

Yea I meant keep the PCV valve in place but change the breather tube to a small filter.

On 4.3L V6 engines and some V8's with TBI injection they had what people refer to as a puke ring below the air cleaner assembly. This was just a metal spacer with a tube in it to facilitate a breather hose. With this ring right above the TB it would allow oil into the air intake system and would cause all sorts of nasty buildup in the throttle body. So the solution was to ditch the puke ring and replace the breather hose with a small filter.

Yes what you have in mind with the TBI's is exactly the same thing we have going on, and essentially what we could do.

I still think if someone tested it, the e-vac setup is probably the way to go... that would ditch the PCV system all together and replace it with something that will pull a good vac at WOT.

From what I've been reading, you would be switching from an Closed PCV system to an Open one by removing that tube and putting a breather on it.

Open PCV Systems
The open system draws fresh air though a vented oil filler cap. This presents no
problem as long as the vapor volume is minimal. However, when the crankcase
vapor becomes excessive it is forced back through the vented oil filler cap and
into the open atmosphere. The open PCV system, though successful at removing
contaminated vapors from the crankcase, is not completely effective as a
pollution control device.
Closed PCV Systems
The closed PCV system draws fresh air from the air filter housing. The oil filler
cap in this system is NOT vented. Consequently, excess vapor will be carried
back to the air filter housing and from there into the intake manifold. The closed
system prevents vapor, whether normal or excessive, from reaching the open
atmosphere. The closed system is very effective as an air pollution control
device.

One other tidbit I got from a Ford Forum.

Closed PCV systems are required in MAF systems to ensure an un-metered air (vacuum leak) condition is not present.....

Makes sense because the PCV could be allowing air into the intake which is pulling from open atmosphere through the added filter, so therefore any air going in that way is un-metered and can result in a hard tuning project.