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  • 92CelicaHalfTrac

    Feb. 6, 2012 1:40 p.m. 92CelicaHalfTrac SuperDork

    Decided i hated the plastic Summit one i got for the Escort. It's huge, ugly, and just... i don't like it.

    But, it's also brought up another area of discussion that i just don't understand.

    Buddy told me i should tie in PCV still to intake manifold. (That'll be a trick, since i won't really have a "manifold.") Said it had something to do with keeping the rings sealed.

    Can anyone comment on this?

    In this picture, i'm guessing the nipples are PCV, and the hole on the front one (Has the Mazda logo) is a vent.

    Can i just run them all to a vented catch can and NOT route back into engine? Or is that a problem?

    Depending on answers, there will probably be a second part to this question.

  • mad_machine

    Feb. 6, 2012 1:51 p.m. mad_machine SuperDork

    if it doesn't have a manifold.. what does it have?

    I know on my fiat, the vapour line from the seperator on the block, went to a nipple on the airfilter housing.. so it could suck the oil vapours into the engine to be burned

  • 92CelicaHalfTrac

    Feb. 6, 2012 1:55 p.m. 92CelicaHalfTrac SuperDork

    mad_machine wrote:

    if it doesn't have a manifold.. what does it have?

    I know on my fiat, the vapour line from the seperator on the block, went to a nipple on the airfilter housing.. so it could suck the oil vapours into the engine to be burned

    ITBs.

    I'm not worried about vapors or smells at all... it's just the ring sealing thing he mentioned that has me worried.

    And come to think of it, i tried to vent the PCV on my MX6 to air once, blocked off the connection at the manifold, left the valve cover open on that line, and the car DID smoke on deceleration in particular.

    What i'm not sure of though, is if it was smoking because the vacuum wasn't there from the manifold to pull the valve open? Or if it was rings not sealing? Wonder if i would have seen smoking if i removed the valve entirely.

  • alfadriver

    Feb. 6, 2012 1:59 p.m. alfadriver SuperDork

    In reply to 92CelicaHalfTrac:

    Based on what appears to be in the cam covers along with the nipples, my guess would be that the one on the left, which is the front one, would be the fresh air supply INLET. This would be where you plum the line from post air cleaner into the engine. The one on the back appears to have something in the cover along with it, which I would guess is an oil separator of some type- probably a mesh or some other thing like that. That would be the outlet, and is plumed to a valve + to the intake manifold.

    How you plumb it depends on what you are using the powertrain for. If you want to drive it everyday, I would suggest to plum similar to the factory. I'll briefly mention that PCV emissions are quite a bit more than engine out. On that note, since this is underhood, and pretty darned close to where you pick up fresh air for the cabin- that is very stinky. Even without a catalyst, you are better off burning it via the combustion chamber.

    When you say you wont have a manifold, what do you mean? Intake ports open to the world? Even with port throttles you have a manifold of some kind. And even with that, you can plumb the pcv to be burnt.

    As for the ring seating thing- I've not heard it put that way, but I know it's possible to get ring flutter if the crank case isn't ventillated reasonably well. Will this engine do that? No idea. But I'd bet the engine will run even if you vent the PCV to the ground.

  • 92CelicaHalfTrac

    Feb. 6, 2012 2:08 p.m. 92CelicaHalfTrac SuperDork

    In reply to alfadriver:

    Hrmmm... i'm unfamiliar with the concept of an air "inlet" except when a PCV valve would open under vacuum. I'll have to do some reading.

    Won't be driving this every day, SMF car. I do know how stinky it can be, though.

    Ok, so ring flutter can happen if it's not vented well enough. I'm thinking that gutting that whole setup and routing it all to a catch can with larger bungs could very well vent BETTER than factory and should cause no problems concerning rings, correct?

    Here's what i meant by "don't have a manifold." There IS a big vacuum log on it all, but i'm not sure how i'd tie into it from valve covers, and i'm not real convinced i'd like to.

    IMGP4383

  • Sky_Render

    Feb. 6, 2012 2:14 p.m. Sky_Render Reader

    First, read:

    Crankcase Ventilation Explained--N/A Edition

    Having ITBs complicates matters due to lack of an intake manifold. You can fix this by constructing a plenum before the ITBs (a la RB26DETT), but that might not be what you want to do.

    The problem is that on deceleration, there is essentially no air entering the engine, so having the crankcase ventilated to the airbox has almost no vacuum under those conditions. That's why a PCV valve is helpful; it pulls vacuum from the intake manifold during hard deceleration.

    You could try using a vacuum pump (expensive) or a dry-sump setup (even more stupid expensive). Another solution might be to plumb multiple vacuum lines to the valve cover. I've seen some 9-second Honda civics sporting four (4) vacuum lines from the valve cover to a vented catch can.

  • alfadriver

    Feb. 6, 2012 2:17 p.m. alfadriver SuperDork

    In reply to 92CelicaHalfTrac:

    PCV systems are designed to flow air through the engine to keep vapors down. So fresh air is supplied into one area, and then taken out from another. Since the manifold is normally below atmosphere, flow will always happen. Normally, the PCV valve and/or the check valve on the inlet side has some kind of restrictor in it to regulate the flow volumes to a pretty constant amount.

    If you are curious how it's plumed, there should be a sticker under the hood to display how the air is supposed to go.

    As for what you have, if you plumb it that there's clean air going in the front (say a mini sock filter like what you have) including a check valve (so that it doesn't push air back out), and then plum the rear (including the PCV valve) to the vacuum log, it should work fine.

    OR, plum the rear to a secondary vortex generator (Alfa's had this kind of set up, and I think you can get one from flyin miata), which will take the oil out of the PCV flow, and then plum the air into one of the filters.

    Again- it kind of depends on what you intend to do with the car. Some racing bodies don't want the PCV to be burnt for some reason. Can't figure why... Not only do I not like the smell, I'm not a big fan of another place that oil is making a mess....

  • mad_machine

    Feb. 6, 2012 2:17 p.m. mad_machine SuperDork

    even ITBs have a small manifold.. could you plumb a line into each one that feeds into a central "block" that runs from the PCV line?

  • 92CelicaHalfTrac

    Feb. 6, 2012 2:21 p.m. 92CelicaHalfTrac SuperDork

    Sky_Render wrote:

    First, read:

    Crankcase Ventilation Explained--N/A Edition

    Having ITBs complicates matters due to lack of an intake manifold. You can fix this by constructing a plenum before the ITBs (a la RB26DETT), but that might not be what you want to do.

    The problem is that on deceleration, there is essentially no air entering the engine, so having the crankcase ventilated to the airbox has almost no vacuum under those conditions. That's why a PCV valve is helpful; it pulls vacuum from the intake manifold during hard deceleration.

    You could try using a vacuum pump (expensive) or a dry-sump setup (even more stupid expensive). Another solution might be to plumb multiple vacuum lines to the valve cover. I've seen some 9-second Honda civics sporting four (4) vacuum lines from the valve cover to a vented catch can.

    I'll start reading that right meow! But first:

    Riddle me this... if under decel there's no air entering the engine, wouldn't crankcase pressures not be much of a problem? If you have to present vacuum to the system to pull anything out, having too much pressure isn't anything to worry about under that scenario, right?

    If there was pressure, and all that stuff was open (valves removed), it would just vent out via any pressure from the crankcase, correct?

    Covers plumbed like this are what you're talking about.

    I gave thought to plumbing two lines to each valve cover. I'm cool with doing that, the next trick (and the next question) would be to find a catch can that would work for all that. My main concerns are:

    1) i don't want to mess up the rings (doesn't seem to be an issue related, beyond having TOO MUCH pressure)

    2) Don't really want a ton of smoke on deceleration all the time.

  • alfadriver

    Feb. 6, 2012 2:22 p.m. alfadriver SuperDork

    BTW, I ask about application, as the answer of what can or should be done changes.

    If this was a challenge car, and only drive at the event, I would say venting will be ok, and as long as you monitor oil level, burning a little isn't huring anything. If this was a daily driver, I'd plumb it up the best I can to avoid getting horrific headaches.

    Race car for the track, somewhere in between.

  • 92CelicaHalfTrac

    Feb. 6, 2012 2:22 p.m. 92CelicaHalfTrac SuperDork

    mad_machine wrote:

    even ITBs have a small manifold.. could you plumb a line into each one that feeds into a central "block" that runs from the PCV line?

    Lost me there....

    You're saying plumb a line from each body?

  • 92CelicaHalfTrac

    Feb. 6, 2012 2:23 p.m. 92CelicaHalfTrac SuperDork

    alfadriver wrote:

    BTW, I ask about application, as the answer of what can or should be done changes.

    If this was a challenge car, and only drive at the event, I would say venting will be ok, and as long as you monitor oil level, burning a little isn't huring anything. If this was a daily driver, I'd plumb it up the best I can to avoid getting horrific headaches.

    Race car for the track, somewhere in between.

    Sorry... i keep avoiding that question, not on purpose, i assure you.

    Not a daily driver.

    Dedicated AutoX car that might see HDPEs/Trials at some point in its life.

  • 92CelicaHalfTrac

    Feb. 6, 2012 2:26 p.m. 92CelicaHalfTrac SuperDork

    alfadriver wrote:

    In reply to 92CelicaHalfTrac:

    PCV systems are designed to flow air through the engine to keep vapors down. So fresh air is supplied into one area, and then taken out from another. Since the manifold is normally below atmosphere, flow will always happen. Normally, the PCV valve and/or the check valve on the inlet side has some kind of restrictor in it to regulate the flow volumes to a pretty constant amount.

    If you are curious how it's plumed, there should be a sticker under the hood to display how the air is supposed to go.

    As for what you have, if you plumb it that there's clean air going in the front (say a mini sock filter like what you have) including a check valve (so that it doesn't push air back out), and then plum the rear (including the PCV valve) to the vacuum log, it should work fine.

    OR, plum the rear to a secondary vortex generator (Alfa's had this kind of set up, and I think you can get one from flyin miata), which will take the oil out of the PCV flow, and then plum the air into one of the filters.

    Again- it kind of depends on what you intend to do with the car. Some racing bodies don't want the PCV to be burnt for some reason. Can't figure why... Not only do I not like the smell, I'm not a big fan of another place that oil is making a mess....

    Heh, yep... i gotta do a bunch more reading... Secondary vortex generator?

    I don't have a sticker under the hood that'll tell me vacuum diagram for this motor. Car came with a BP 1.8 DOHC i4, swapping in KLZE 2.5 DOHC V6. I can find the vacuum diagram for the KLDE, but i'm not sure how helpful it'll be at this point. I might be able to strip out the emissions stuff, VRIS, and others from the DE diagram to apply to ZE without factory manifold...

  • alfadriver

    Feb. 6, 2012 2:27 p.m. alfadriver SuperDork

    In reply to 92CelicaHalfTrac:

    Rings will flutter based on pressure differential. If the PCV is being routed toward the intake, the crank will be under a depression based on flow and restrictors... So the rings see low manifold pressure on one side, lowish crank pressure on the other.

    OTOH, if the crank is vented to air, it's at atmosphere- so the rings see low manifiold pressure on one side, and atmospheric on the other, which can cause flutter- and it sounds like yours do.

    The rings are not getting damaged- it's just that the flutter doesn't scrape up all of the oil, and some gets burnt.

  • alfadriver

    Feb. 6, 2012 2:30 p.m. alfadriver SuperDork

    This.

    But picture it runs more up and down, PCV goes into the lower inlet, the vortex spins the heavy oil to the walls (and down to the bottom and returned to the sump) "clean" air comes out the top (center of the vortex). It's how dyson vacuums work.

  • 92CelicaHalfTrac

    Feb. 6, 2012 2:38 p.m. 92CelicaHalfTrac SuperDork

    alfadriver wrote:

    This.

    But picture it runs more up and down, PCV goes into the lower inlet, the vortex spins the heavy oil to the walls (and down to the bottom and returned to the sump) "clean" air comes out the top (center of the vortex). It's how dyson vacuums work.

    Ah ok... so from what i'm gathering....

    I should use one of those or a sealed catch can inline with the PCV side that sees vacuum from the "manifold" under deceleration.

    And the other "venting" port(s) are ok to run to a vented catch can, don't have to return anywhere within the system.

    But at the core, the "vacuuming" aspect is important.

    And i should probably look into dry sump oiling. Le sigh.

  • 02Pilot

    Feb. 6, 2012 2:49 p.m. 02Pilot Reader

    alfadriver wrote:

    In reply to 92CelicaHalfTrac:

    Rings will flutter based on pressure differential. If the PCV is being routed toward the intake, the crank will be under a depression based on flow and restrictors... So the rings see low manifold pressure on one side, lowish crank pressure on the other.

    OTOH, if the crank is vented to air, it's at atmosphere- so the rings see low manifiold pressure on one side, and atmospheric on the other, which can cause flutter- and it sounds like yours do.

    The rings are not getting damaged- it's just that the flutter doesn't scrape up all of the oil, and some gets burnt.

    Not to threadjack, but I'm chasing a very frustrating oil consumption situation (in my 2001 BMW 525i) and this discussion is relevant, I think. Basically, I'm seeing oil pulled into the cylinders on deceleration. I've had the valve seals replaced, and the PCV (CCV is what BMW calls it) is functioning properly (pulling a steady 3" of water across the rev range). This eliminates the two obvious potential causes. Would this ring flutter phenomenon possibly occur because of the low vacuum pulled by the BMW PCV system, the differential of which with the manifold would be highest under deceleration? Would it cause oil to be pulled into the cylinders under deceleration only (no problems under load), mimicking bad valve seals?

    Oh, and to provide something useful to the OP, that oil separator is from a BMW X5 V8, p/n 11151705237.

  • alfadriver

    Feb. 6, 2012 2:57 p.m. alfadriver SuperDork

    In reply to 02Pilot:

    I'm not all that well versed in ring flutter. But in terms of your car, I would doubt that BMW would design an engine where the rings would flutter and burn oil at the same crank vacuum that they originally designed it to run in.

    possible, but would be odd. They would have tested this a lot.

  • 02Pilot

    Feb. 6, 2012 3:22 p.m. 02Pilot Reader

    alfadriver wrote:

    In reply to 02Pilot:

    I'm not all that well versed in ring flutter. But in terms of your car, I would doubt that BMW would design an engine where the rings would flutter and burn oil at the same crank vacuum that they originally designed it to run in.

    possible, but would be odd. They would have tested this a lot.

    Understood. I suppose I should have mentioned that the car has 140k miles on it now, and that the problem has only appeared in the last 10k miles or so, so it may be related to wear.

    I should also note that the all-aluminum M54 is developing a reputation as an oil-burner (at least moreso than most contemporary BMW engines), that the CCV is a horrible, failure-prone design (failure modes include sucking oil directly from the pan into the intake, potentially hydrolocking the engine), and that even with CCV and valve seal replacement, I'm not the only one still seeing oil consumption.

    If I wanted to experiment with higher crankcase vacuum, how high should I go? Can limiting crankcase vacuum be accomplished with a simple orifice, or would I need a valve of some sort?

    Thanks for helping me with this; it has been a huge source of frustration in the last few months. And to the OP, apologies once again for the diversion - I'll happily move to a separate thread if you'd prefer.

  • 92CelicaHalfTrac

    Feb. 6, 2012 3:24 p.m. 92CelicaHalfTrac SuperDork

    Heh, no apologies necessary.

    I'll move this into another direction, though...

    Any recommendations for a vented catch can with 2-4 inlets? This is one of the few times i wish i was working with a Honda so i could get a pimpy application-specific bad boy.

 
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