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SuperG
09-27-2006, 09:56 AM
I installed an air/oil filter after the PCV and it's certainly working...several ounces per week! I am thinking of attaching a second filter just to see if oil is still getting through.

I also noticed oil on the air intake ducting from 2 sources; the crankcase vent tube (but only some spotting) and the hose that runs beneath the IAC. The hose runs through a plastic, triangular box, then continues to the air inlet side. I am thinking about installing an air/oil filter there as well.

This concerns me since oil is most likely getting all over the impellar and into the combustion chamber.

Also, following hard acceleration, I see smoke coming from the tail pipes. Based on a previous post from Aussie suggesting oil getting past the rings, how can the pressure under the valve covers increase such that oil is blasting past the rings? If this is happening, how does one remedy this?

SuperG
09-28-2006, 08:18 AM
Update: I removed the S/C discharge tubing to install some bling over the plug covers...I found oil inside the tubing, so I looked into the discharge side of the S/C and found oil there, also.

I am fairly certain this is coming from that tube under the IAC. What is that and what air/oil separator can I use, as the tube is much larger that the 3/8" coming from the PCV.

ausie
09-29-2006, 08:26 AM
I may have been drinking too much coffee on that one. Actually, if you remove the PCV system entirely without some sort of breather system in place there may be a chance that the pressure in the bottom half could cause oil to pass the piston rings. Keep in mind that most if not all motors leave a film of oil on the cylinder walls which part of the piston seal. However, if the crankcase builds up too much pressure and does not get equalized by some means, the oil left behind on the cylinder walls may become excessive. That would not find its way back into the intake tract unless it got recirculated by the EGR valve. I do not believe that is the case here.

I keep forgetting what year your car is.... I believe the larger line (if it connects to the IAC valve) should be the throttle body bypass line since you stated it connects to the low pressure side of the supercharger. 99/01 throttle bodies have the duct work built into the throttle body and the earlier model years may use a similar setup to that of the mustang GT (guessing).
Do you have a boost bypass or dump line connected to the high pressure side? If so, the triangular box may be the dump valve. The source for oil invading the intake tract as far as I can tell would be the crank case breather line and PCV line. If the breather line is located up stream (closer to the air filter) than the boost bypass line (or if it is the throttle body bypass), oil will follow the source of vacuum once it enters the intake tract. You probably only need to place an oil filter separator on the crank case breather line.

The alternative would be to remove the PCV system and connect the crancase vents to a common racing type breather with an oil catch can. Using just the small plug in filters would cause a mess.


I installed an air/oil filter after the PCV and it's certainly working...several ounces per week! I am thinking of attaching a second filter just to see if oil is still getting through.

I also noticed oil on the air intake ducting from 2 sources; the crankcase vent tube (but only some spotting) and the hose that runs beneath the IAC. The hose runs through a plastic, triangular box, then continues to the air inlet side. I am thinking about installing an air/oil filter there as well.

This concerns me since oil is most likely getting all over the impellar and into the combustion chamber.

Also, following hard acceleration, I see smoke coming from the tail pipes. Based on a previous post from Aussie suggesting oil getting past the rings, how can the pressure under the valve covers increase such that oil is blasting past the rings? If this is happening, how does one remedy this?

SuperG
09-29-2006, 06:55 PM
Well, I guess I should ask this: In which direction is flow in the crankcase vent tube and in the tube from the bottom of the IAC? I am assuming it is from the valve covers to the air intake.

I took a couple of pics:

IAC removed - clean. What is the function the ports beneath the IAC? I also highlighted the plastic, triangular box.
http://memimage.cardomain.net/member_images/11/web/2183000-2183999/2183045_16_full.jpg

The larger tube from the IAC is wet with oil, the smaller from the crankcase is dry.
http://memimage.cardomain.net/member_images/11/web/2183000-2183999/2183045_15_full.jpg
I am looking for a large air/oil separator for the 1" from the IAC side.

ausie
09-30-2006, 10:49 AM
I believe that the larger hose is the bypass for the throttle body as it connects to the metered inlet tube to the small plastic box (which is sort of a noise suppressor chamber) before it passes onto the elbo which is located to the left and above the "09" date code on the picture. When the throttle blades are closed, the vacuum of the motor will draw air into the intake plenum through the IAC valve. Since the valve will open by vacuum pressure (as well as a preloaded spring to aid in movement) , the ECU will apply voltage to the solenoid to keep it closed and the associated signal pulses will effectivley control the idle speed of the engine. The plastic box was placed in the IAC air flow path to reduce noise assiciated with the air surges. Placing a air/oil separator on the IAC path may lead to idle control issues since that would greatly restrict the air flow. It may be possible that the air silencer box may still have oil in it when you had the other issue with the supercharger bearing. The IAC valve may still be open while the engine is operating from throttle control (driving the car) and would become a paracitic pressure loss if there is not enough boost to force it closed. How clean was the IAC valve? if you have alot of oil flow through the hose, at least the air silencer is stopping it to some degree if the valve is not saturated.
As far as the PCV system, think of the full term positive crankcase ventilation system. At idle air is drawn into the passenger side valve cover as long as the PCV valve is open. The air flow is controlled by the PCV valve which is a gravety assisted check valve. When the valve is suspended at the top of the valve body by the engine vacuum, the valve is open. When accelerating, the pressure differential changes which temporarilly causes the flow to change direction until the valve drops all the way to the bottom position which is the closed position. Crankcase pressure will increase as a result of gasses formed during combustion which may pass by the rings (blow-by) and will ultimately exit through the breather line. Blow-by occurs in all engines, just how much is the issue. With Forced induction, there is rapid changes in plenum pressures as well as in the crankcase which tends to create more displacement of engine oil that is splashing around under the valve covers which winds up in the intake plenum through the PCV line or through the breather line. If you noticed that all of the air flow through the PCV system is metered air. Technically you could connect the intake breather hose directly to the pcv valve without any issues but that would not allow for the harmful volitile vapors to be recycled. There are several types of methods to prevent motor oil from entering the intake plenum and the air/oil separators do work to some degree as well as some air/oil separator catch cans (GREEDY manufactures them for imports) There are some others that do not use the PCV system which use a common air filter element and have two nipples (one for each valve cover) as well as a oil release lever at the bottom. One could use one of those by connecting the breather line to where the air filter sits, along with a "T" section to run an inline PCV check valve to the intake plenum. The two valve covers would be connected to the side ports and the canister would collect the oil that ends up in the lines. Not sure how something like that would work since nobody has one that would fit the deisign requirements. A dual chambered unit would or two individual ones with single inlet and outlet ports would at least trap any oil in the lines and still permit the crankcase ventilation as it was originally designed. If you need to add another air/oil separator, connect it to the breather line only (not to the IAC feed). The air flow direction for the breather line should be in reverse (arrow pointing toward the intake pipe so the collected oil will stay in the catch can).

SuperG
09-30-2006, 09:48 PM
OK, then if I read that correctly, during idle, the IAC opens allowing fresh, metered air into the plenum while the throttle plates are in the closed position. Are you suggesting if the IAC is not operating properly, that it might remain open during boost? If that's the case, flow reverses from the plenum to the air intake...however...where does the oil come from? There should not be any inside the plenum, right? I doubt there is that much oil still getting through from the PCV valve.

BTW, the amount of oil I see from the supercharger to the trottle body is exactly the same I saw this summer when I sent the unit back to Vortech. Although they rebuilt it, I have a sneaky suspicion that it did not need to be. Therefore, I strongly believe what I am experiencing now is exactly what happened this summer, although I have all eight cylinders firing this time and I am trapping some of the oil.

Now I am wondering where on earth that oil is coming from. Tomorrow, I am installing that second separator, then running the engine above idle and watch the IAC hose at the intake side (I'll disconnect it and hold a white paper towel in front of it) to watch for oil. I will also try the crankcase line as well.

ausie
10-01-2006, 07:32 AM
(quote) OK, then if I read that correctly, during idle, the IAC opens allowing fresh, metered air into the plenum while the throttle plates are in the closed position.

:cool: Yep, that is the job of the IAC (Idle Air Control). It does two things, acts like a choke at startup and maintains the idle speed (between shifts, and whenever the throttle blades are closed). :cool:

(quote) Are you suggesting if the IAC is not operating properly, that it might remain open during boost?

:cool: This may be plausible for naturally aspirated form in that the valve may float if there is no applied voltage to the solenoid. Forced induction would create enough of a pressure differential to move the valve in the closed position unless there is a voltage on the solenoid which whould keep the valve from closing. :cool:

(quote) If that's the case, flow reverses from the plenum to the air intake...however...where does the oil come from? There should not be any inside the plenum, right? I doubt there is that much oil still getting through from the PCV valve.

:cool: I doubt that all of the oil is comming from the PCV line. It is obvious that is one source since you already have the air/oil separator on that line. The secondary source is the breather line which is a common issue with the 03/04 Cobras. Often I had found pools of oil in the intake pipe and a small flow of it comming out of the throttle body when I opened the throttle blade. I now have an SHM breather oil separator filter canister attached to the valve cover to reduce the amount of oil entering the throttle body (breather line attaches to the canister which is attached to the valve cover). There is a difference of course between a roots and a centrifugal where the roots blower produces pressure in the lower plenum and dumps it back into the upper plenum (behind throttle body) which tends to provide back pressure into the PCV line. The centrifugal type such as the Vortech produces pressure in the pipe before the throttle body and when it dumps boost it brings it back to the low pressure pipe. The pressure pulse from the boost bypass valve may be enought to momentarily change the flow characteristics of the PCV system which may cause a surge to push out oil from the crankcase into the lowpressure intake side of the vortech.

(quote)BTW, the amount of oil I see from the supercharger to the trottle body is exactly the same I saw this summer when I sent the unit back to Vortech. Although they rebuilt it, I have a sneaky suspicion that it did not need to be. Therefore, I strongly believe what I am experiencing now is exactly what happened this summer, although I have all eight cylinders firing this time and I am trapping some of the oil.

Now I am wondering where on earth that oil is coming from. Tomorrow, I am installing that second separator, then running the engine above idle and watch the IAC hose at the intake side (I'll disconnect it and hold a white paper towel in front of it) to watch for oil. I will also try the crankcase line as well.

:cool: Do not use a paper towel, best to use a woven cotton shop towl instead. I have already sucked in part of a paper towel into my intake and was a major pain to recover it. I would probably start with the small air box attached to the IAC hose by removing it and cleaning it out with throttle body cleaner in case there is trapped oil inside it. Also, I would inspect the air filter for oil saturation. Also if you have an air cooler mounted on the intake, that could be an area that would hold trapped oil as well. If the oil seems a bit excessive clean all of the pipes and hoses and re-assemble and see if it continues (try the air/oil separator on the breather line, you can find fittings that will mate with the hose size in some hardware stores or at NAPA (I think the threads on the air/oil separator are 1/4 NPT and the other hose is close to 5/8". A threaded adaptor will work as long as you use a hose clamp. I would double check the blow-off (boost bypass) valve where it connects to the low pressure intake pipe for signs of oil.

At this point, you could get a rubber cap to block off the PCV line fitting on the upper plenum (use a clamp) and cap off the breather line fitting on the intake pipe with a rubber end cap and clamp. Get those small filtered breathers from any auto parts store (you will need two of them). With the PCV system removed and using the filtered breathers in the valve covers, there should be no source of oil to enter the intake except for the supercharger if the seals were not properly repaired. Note that the use of the valve cover breathers will allow for oil to eventually saturate the elements of the breathers and will result in oil on the valve covers. They will help you diagnose where the oil is comming from but I would not use them for long term. I hope this helps you find the source of oil :thumbsup:

Eric :cool:

SuperG
10-01-2006, 09:52 AM
Thanks, Eric! I will tackle this today and let everyone know whats going on...

SuperG
10-01-2006, 09:37 PM
OK...First, I added a 2nd separator to the PCV line. I placed it after the 1st separator, close to the plenum. Interestingly, I installed it backwards and noticed the filter changed from white to light brown. I reinstalled it correctly (arrow pointing to the plenum) and in the short time I ran the car, the filter got a little darker. I assume under boost, the small amount of contaminants in the plenum were going back trough the PCV a bit. I'll check it again tomorrow.

Second, I began testing the IAC air line and the crankcase vent. The engine died when I pulled the IAC hose off the air intake during idle. But before that, I could easily see the air being sucked into the engine. Then I revved the engine and removed the IAC line and I expected it to discharge air, but it REALLY had a suction! New IAC required?

Third, I disconnected the crankcase vent at the air intake side and under both idle and high revs it always flowed from the valve cover to the air intake, however, not one droplet of oil was observed.

In both cases in which I removed a line, I also revved the engine really high and let off the throttle. Never did I see any oil nor did I see any smoke from the tailpipes. But I do observe smoke when I decelerate. Is this something that happens because I have the car in gear?

Now I am perplexed even more so. There seems to be no oil entering the air intake from the possible sources.

So I am back to the supercharger. If it is still leaking oil, it can blow oil through the discharge piping AND when boost is relieved from the discharge side, it is relieved to the air intake, just before the blower.

This is all I can come up with now...

ausie
10-02-2006, 08:18 AM
IAC valve: sounds like it is working fine. The only time you should consider replacing it is if the idle speed cannot be controlled and you could not find any air leaks. If it is disconnected it will stay open all the time and idle will ramp up to about 2500 rpm. If your engine has no issue maintaining an idle speed of 600 to 900 rpm once warm ( or at least below 1000rpm) the IAC is working as it should. Since the motor creates a vacuum with a pressure much lower than that of the atmospheric conditions, there will be a good suction at the hose end. This is one reason why you found oil in this hose since it will pull it in if it found its way in the intake.

There are two contributing factors that would cause the aluminum oxide pellet in the air/oil separator to change in color. The vapors created by hot engine oil are not clear. Some of it is comprised of fuel vapor as well as some other combustionalbe gasses created from the oil as it is heated (one reason why not to run extended periods on the same oil since unburned fuel will wind up in the oil over time). The other contributing factor is the recirculated exhaust from the EGR valve. When both become combined in the intake plenum along with heat, you will get a varnish build up on the internal surfaces which is normal with fuel injected vehicles. Much of this can be cleaned with routine maintanance (never really listed though) with throttle body cleaner every now an then.

The reason why you found some pressure on the breather line is that the engine creates pressure on both sides of the piston. The engine is basically operates like an air pump or compressor. Since the pistons and crank shaft are moving, there is some pressure created in the crankcase. Since the pistons form a seal, the up and down strokes of the pistons will form a pressure differential on the bottom half as well. One reason why motors have a breather line was to an attempt to equalize the pressure differentials between the intake and crankcase which helps maintain good oil pressure and flow. The PCV system works in several ways, one it balances the pressure differentials created by the motor. Two, it draws in the combustionable fumes from the heated oil to be recycled in the engine. And finally it is bi-directional. The PCV valve is a type of check valve that typically works in one direction. Once the valve closes, flow is reversed through the breather line. Note: if you removed either the PCV line or breather line from the valve cover there will be alot of oil spitting out which is cause by the valve train, rockers, etc.... Those droplets of oil when coupled with vacuum pressure or positive pressure will displace the mist of oil.

With the engine out of gear and just applying throttle probably will not recreate all that is happening. When the engine is under load it operates differently than when there is no load. Rate of burn of the fuel in the combustion chamber as well as how much fuel is added to overcome the loaded forces such as gravity, inertia, friction, etc....

If you see smoke under hard acceleration and if it is not black but bluish white then I would worry. Typically once drop the throttle quickly, the air/fuel mixture may be rich for a brief period which may cause a puff of smoke out the back end.

I would place the 2nd air/oil separator on the breather line and see if it collects oil. Chances are it probably will since you noticed some air flow out of the valve cover. The PCV systems in our cars is over designed meaning it flows too well and does not have the proper baffles to prevent oil passing out of the crankcase. Adding the air/oil separators will provide some flow restrictions but still permit the flow of gasses. Case in point, with my stock 2001 Cobra, I would typically loose up to 1 quart of oil every 3000 miles (which varied with the type of oil used). That was just enough to cause engine issues at around 16k miles due to carbon buildup and oil buildup in the intake and combustion chamber. I used one of those air/oil separators and noted that I could fill it up entirely within 50 miles of driving. With my 04, I did not want to take any chances, so I have two, a home made one on the PCV line (machined out of billut aluminum from work) and a foam and mesh filter on the breather side. The nice thing about them, I do not have to dump the canister of oil since they dump back into the valve covers. Billetflow does make one similar and probably better than the home made one I now have on the PCV line. The other is the SHM canister filter.

A brief inspection of the throttle body or Pressure pipe connected to the supercharger and throttle body would be a starting point for an oil seal issue. If the supercharger was leaking, the most amount of oil would be in that pipe. Keep in mind that some oil may be from a different source like the breather hose so once you eliminate oil from the breather line can you diagnose if the source is from the supercharger. Another link would be a saturated blow-off valve or boost pressure refief valve since it dumps back into the low pressure side, the oil would also exit with the air when it opens.