PCV system problems, still...Need help..

[daddystang]

I've been working on my PCV system adding a second PCV valve to the drivers side valve cover to control the oil going into my intake, because my spacer was getting soaked with oil. I now have an air/oil seperator from Lowes installed with both PCV valves going into the seperator first, then a hose going into the intake. I was using a PCV valve on the valve cover that was not for a mustang, and it was still sucking some oil into the intake as was evident by the smoke out the tail pipes. I installed the correct valve today, and dumped the oil out of the seperator to start fresh. I took a 5 minute spin, came back, and the seperator was about half full of oil. Why is so much oil getting sucked up through the PCV system?
A foot note: I had no smoke at all before working on the PCV system.

I have a metal plate installed below the pcv valve on the valve cover. I am completely stumped on this. I'm hoping some of you guys have installed a second PCV valve, and can help me correct this.

Sorry for the long post, and thanks for any help you can provide.

Joe

 

[vristang]

Sorry things aren't working better for you...


Here are a couple of things that should help get you on the right path.
Tests to run
Compression Test
Leakdown Test
Vac gauge on the crankcase (you will need to seal the temporarily seal the crankcase from atmosphere and intake pressures.)

I'm not really sure what else to suggest... hopefully one of these tests will reveal something meaningful.

jason

 

[daddystang]

Thanks vristang. I was reading a very long thread that was opened a while back on the problem of oil in the intake, and decided to try a few things. One of the things one of the guys tried was to block off the pcv valve on the back of the intake, and just use the new one on the valve cover. Here's what I've found.

First I blocked off the valve cover pcv valve that I just installed, and ran the one on the back of the intake through the air/oil seperator. When I started it, I immediately started seeing oil spray/drip into the catch bottle.

Next I did just the opposite, and with the back one blocked off with a bolt in the hose, I ran just the valve cover pcv valve through the seperator, and started it. I didn't really see any noticeable oil going in the catch bottle. When I would hit the gas I would see air spray into the bottle, but no oil to speak of.

On the other thread "Putting a stop to oil consumption through the pcv valve". Hink put some washers on the screen in the back of the intake as sort of a baffle along with some other things. I'm going to start trying some things so that I can get the back one connected again, but it seems the back pcv valve is where all my oil is coming in at. Once I connected the second one in series with it, that's where my problem started. I'll post again with some drive results today. If you have any thoughts about running just the valve cover pcv please let me know, or if anyone else has found a fix please chime in.

Thanks,
Joe

 

[vristang]

Joe,
Good detective work!!!

Do you know if the there is a baffle under the lower intake?
How large is it?

jason

 

[daddystang]

Well...... I took it for a spin today, and when I got home the catch bottle was half full again. Bummer...

So, now I've got the valve cover valve blocked off, and the back pcv valve going through the seperator to see how fast it fills up. I'm going to take it for a ride soon, so I'll let you know what I find.

I'll have to look and see if there is a baffle on the back of the intake. I don't remember if there is one. I hope there is, but if not I guess I'll pull the lower intake off, and make one there too.

I just don't under stand why the valve cover pcv sucks so much oil, I made a baffle for that one. When I pull the pcv valve out of the valve cover while it's running I don't see a ton of oil on top of the baffle. Any thoughts?

Thanks Jason for your help.

Joe

 

[daddystang]

I'm throwing this out there to see what you guys think.

I'm going to try running the valve cover pcv into the seperator, and then a hose out of the seperator into the intake. On the bottom of the seperator catch bottle there is a drain valve. What if I run a hose from that drain valve to the pcv location on the back of the motor, hog out an old pcv valve and connect the hose so that the oil in the catch bottle runs back into the motor.

I'm thinking that the air coming into the seperator would push the oil out of the drain valve through the hose and back into the engine.

Any thoughts as to the effectiveness of this setup?

Thanks...
Joe

 

[vristang]

If the drain valve is exposed to crankcase pressures, then it will be the same as having a second inlet to the separator.
There will still be intake manifold vac and pressure in the crankcase.
Flow will still be from the crankcase to the intake.

I don't think this would be an effective drain, but I haven't tried it either.


jason

 

[daddystang]

Yes sir, I see what you are saying, the upper intake would be sucking air in through the side of the seperator at well as the bottom (drain).

Do you think it's possible that the air pressure coming in from the valve cover through the side of the seperator would be strong enough to force the oil out of the bottom of the catch bottle?

joe

 

[vristang]

Ye
Do you think it's possible that the air pressure coming in from the valve cover through the side of the seperator would be strong enough to force the oil out of the bottom of the catch bottle?

joe

Flow will always follow the path of least resistance.
When dealing with pressures, this means you need to look at the pressure differential.

There is a positive pressure in the crankcase, and vac pressure in the intake.
For example,
The crankcase may be at 5psi, and the intake at -15"
The difference between positive 5 and negative 15, is the what will affect flow.

IF there are 2 potential outlets from the separator, one going to a 5psi crankcase, and the other going to a -15" intake manifold, THEN flow will go to the manifold.

(I've mixed pressure and vac units here, and I'm not sure what the pressure numbers should be from the crankcase. The numbers may be made up, but the principles seem sound)

I considered such a setup for a while, but for the reasons above, decided not to spend any time on a setup.

jason

 

[daddystang]

Jason, Thanks for the logical look at my idea, it sounded good when I thought of it.

I put my system together with just the back PCV valve going into the seperator, and then into the intake. I have the one on the valve cover capped off right now. I took it for a spin (about 10 min.), and the catch bottle didn't appear to have anymore oil in it than before I drove it. I did however replace the motorcraft PCV valve on the back of the intake with one that I bought when I started this project. That PCV valve is not listed as one for my year mustang (if a mustang at all). I'm going to drive it more today, and see how it goes. I'll update later today.

Thanks,
Joe

 

[daddystang]

Just an update. Took it out for a spin yesterday, and no new oil in the seperator. I brought it to work today which was about 22 miles, and I'm going to go out and check it shortly. So far so good. I think the new pcv valve is helping/corrected the issue. Who knew......

Joe

 

[daddystang]

Just checked the seperator catch bottle, and the level is still the same. Looks like the pcv valve that I installed on the back of the intake is working correctly where as the stock one that was there was not. I may make a trip back to autozone and pick up another one, and try it on the valve cover to see if it works with both connected. Guess I'll update again later with the part number of the pcv valve I'm using. Hope this is helpful to someone else.

Joe

 

[daddystang]

The number stamped on the new pcv valve I'm using is 2262. I'll get the manufacturer and what year and car it's for this weekend. I got it at autozone.

 

[vristang]

Joe,
Something I noticed a while back was that the separator only seems to get about half full, then it won't hold any more oil.

Obviously, I don't know how 'full' your separator is, but it may be worth dumping it out to confirm things are going as well as they seem.

I'm still curious on that pcv number.

jason

 

[daddystang]

Jason,

I had already emptied the seperator out, so when I say that no more oil was going it I meant it's still empty. I should have been more clear on that.

I may go to autozone tonight to check on the year, make, and model of the pcv valve I'm using. I'm going to get another one, and put it in the valve cover location to see if I can get both working even though just the back one seems to be sufficient. No more smoke, and it seems to be running a little better. I haven't pulled the plugs to check them, but I think maybe they were getting fouled a bit with the oil. I'll update again later.

Joe

 

[Bad92GT]

Hope you can get it fixed, i had MASSIVE problems on my 92.. so bad that i sold the car. I just couldn't ever get it to stop sucking oil. And then the distributor went, and the ac compressor.. in 2 weeks.. and then the alternator caught on fire. I hope you can get it right! Seperators only work so well, mine would catch oil but would be full quick.. very quick. Look into Supra Twin turbo oil seperators

 

[daddystang]

Went to Auto Zone and the PCV valve is made by Luberfiner number PCV1255. I asked the guy at Auto Zone if he could take the part number and tell me what make and model car its for but he said he had no way of doing that. I'm going to put it on the valve cover tomorrow and tie it into the seperator and see what happens. If it starts to suck oil again, I'll just stay with the one on the back of the intake and scrap the one on the valve cover. I hope this is helpfull to others. I'll update again later.

Bad92GT sorry to hear about the problems you had, i know how much of a pain it is to have the intake suck up so much oil. It was bothering me too, which is why I'm going through this hassel to find a fix and hopefully help other guys out at the same time.

Joe

 

[daddystang]

I did a cross reference search at Luberfiner.com, and the PCV1255 is for 91-93 GM products. Hope that helps...

 

[daddystang]

Well I hooked up the one on the valve cover in series with the one on the back of the intake, and the seperator filled up half way after just a ten minute drive.

I'm going to just go with the one on the back going through the seperator. I drove 50 miles with just that one connected, and barely any oil went into the seperator. I must have a problem with the baffle I made for the valve cover. So one day when I have the intake off I'll pull the valve cover and try to reposition the baffel and try again.

I'm just glad I don't have anymore oil going into the intake. I hope this thread has helped someone else with the same problem.

Joe

 

[vristang]

You've done a good job of systematically going through the system Joe

It does sound like the baffle in the vc may need a little re-design...


Let us know if you get it sorted out,
jason