PCV oil residue on the hose?

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gdizzle

gdizzle

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66 dart L6 225 ci.
engine was rebuilt last year. all new hoses etc..

Anyhow I just started to notice there is oil residue on the hose end that connects to the PCV on the valve cover? The PCV is new, the hose is new. It is tight, how is oil getting onto it? The rubber gasket that hold the pcv inplace is also new. I removed the valve and there is some oil inside , enough to cause a drop of oil to fall out. How is there that much oil in there? Isn't this just a vaccum system? The other end of the hose goes to the carb and there is no oil residue over there.
Like a mist of oil is on the hose at the pcv connection? Ideas?

I have removed the pcv and reinstalled my original metal one, and see if the oil returns/. But I am still concerned as to why so much oil is getting past the valve?
 
p4529895.jpg
A picture would sure help. I know what the original 66 setup is supposed to look like but am having a hard time envisioning what you are using.
 
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mguner, that's not a '66 setup in your pic, that's a '61-'65 setup. '66 was the first year for the rubber grommet-mount PCV valve rather than the metal cap. Your question about whether it's an original valve cover is the right one to ask, though; if the OP is using an aftermarket cover (chrome junk from China or nice-but-unbaffled aluminum from Offy, Clifford, etc) then yeah, the PCV valve is going to suck up oil.

Original poster: see this post for the science, and this post and here for the annoying workarounds that have to be done on covers that don't have baffles.
 
My 66 polys used the type shown and they are listed as 64-69 for "some" applications so I wasn't sure in the early slant. I was thinking if a chrome aftermarket cover was used it may not have the baffle box....
 
OP, check your PCV hose itself. It has to be a specific type, that is built to withstand a high vacuum level inside without collapsing. Regular heater hose and other hoese for internal pressure (like fuel) will not do. The fact that there is oil in the PCV end but not at the carb end of that hose is suspicious.

Also, make sure the PCV connection into the carb is not blocked; you should be able to attach a hose and blow through it and have air flow in under the base of the carb. Sometimes these carb PCV ports get blocked with old, hardened oil residue.
 
It is the original valve cover (I think). Here is current pic where I have put in the old PCV valve. I am pretty sure the hose is sturdy type.it has real thick walls.

IMG_3191.JPG
 
Yup, that's the '66-type valve cover and looks like the right kind of hose as well. How many miles on this engine, and what's its state of health? If you warm up the engine to operating temperature, leave it idling, remove the PCV valve and the oil cap from the valve cover, block the PCV grommet hole with your thumb, and put your palm firmly on the chimney where the oil cap goes, how quickly and firmly does your palm get pushed off the chimney by crankcase pressure?
 
Keep in mind too, that as rpm and load change,there will come a point where the manifold will not have enough vacuum to work the valve. At about this time the engine will be producing a fair bit of blowby. The crankcase may actually go to positive pressure. This pressure has to go somewhere. The factory provided a large hose to the air filter house for this purpose. If the pressure backs up in the system it will blow vapors out, anywhere it can.Some blowby is normal.
Is your supply hose connected to the airbox, and open?
 
The large diameter hose between the crankcase breather (oil cap) and the air cleaner would not be present as original equipment on a '66 unless it was a California-spec car. That started in '64 for California, '68 for the other 49 states + Canada. The previous setup has an oil cap/breather vented directly to atmosphere—turn the oil cap upside down and you'll see a ring of holes on the underside. Inside the cap, if it's still in OK condition, is a mesh to keep spiders and rocks out of the crankcase.
 
Oh yeah, sheesh, I forgot.
So then the CC pressure would find it's way out the breather and puke oil vapors onto the VC over there, unless it was severely restricted or the wrong type, in which case, the CC pressure will find it's way out at the weakest seal.
Again some blowby is normal. The PCV's job is to recirculate it. When there's too much for the PCV, it has to go elsewhere, and that is also normal. The trick is defining "normal".
One trick I have used in the past is to remove the dipstick, and plumb a vacuum gauge/fuel-pump tester on there to be read from the driver's seat. Leave everything else alone.Then head for the hiway, and drive it like you normally would. Leave it on there for a few hours checking it from time to time as you are pressing on the gas pedal, and at hi-way speeds, etc.If you see 2psi or less on the gauge when flooring it, as the rpm rises, I would call that probably normal. If you see 4 psi or more, you probably need rings,or a new breather cap. Between 2 and 4, IDK. More thinking might be required.Somewhere between 3 and 4, something's got to give.If you want to see your PCV in action, remove the breather and plug the hole.You probably don't want to drive it this way, cuz if the pressure hits over 4psi, it will almost for sure blow a seal somewhere, and yer not gonna like it.If the PCV hose collapses, buy the proper thick-wall oem type.Remove the tool and reinstall the dipstick and the breather,when you're done.
 
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gdizzle said:
It is the original valve cover (I think). Here is current pic where I have put in the old PCV valve. I am pretty sure the hose is sturdy type.it has real thick walls.
Click to expand...
OK, good. Now check that the passage in the hose connection under the carb is open and not blocked. That's all in addition to the other good suggestions here.

BTW, do you drive the engine a lot with the throttle mashed way down? What do you have for a carb? Have you ever measured the vacuum in the manifold at idle?
 
Hey thanks for these troubleshooting tips. This is what I can update:
The oil breather is the old style, with the mesh inner, and vents to open air.
The carb is Holley 1920, rebuilt and soaked about 6 months ago. I have put about 1000 miles on this car since being rebuilt (9 months ago). The passage on the carb is clean and clear.
I started her up, removed the pcv and oil cap. I plugged the pcv hole with finger and plugged the oil cap with hand. About 6-7 seconds I could feel pressure and then when I removed my hand a big gooosh of air escaped.
I also plugged the hose (with pcv still on meaning i plugged the pcv valve) going to the carb and the engine dropped way down in idle almost to stall but never did.
One thing I did notice, when I have pcv out and the oil cap off, if I insert the PCV back into the hole (grommet) I can hear a very faint change in engine sound. Like is dips just a tiny amount?

Also I have never tested the vacuum pressure, is that an easy thing? I think Oreillys has a pressure gauge I can rent. Where does it go?

I do continue to have a hesitation issue when under load, but that seems to be the bain of my existance and will never be fixed:( Future plans to swap it all over to the Super Six setup this summer.

Ideas?
 
Hey your comment about Dipstick just rattled something in my brain. Since this oil issue seems to be somewhat new, I did make one adjustment about 2 weeks ago. I have this wrong Oil Dipstick that never seated all the way because of oring seal. I recently took it out and cut off the oring (it was like a 1 inch long tappered seal) so that it now fully seals. Is it possible that it was venting through the dipstick and now that it cant vent there it is forcing more through the PCV and thus misting some oil out of the connection? Seems crazy....right?
 
If you want to check vacuum, then connect to the port on the #6 intake runner. Vacuum/pressure gagues don't cost much and are good to have for general work so I'd recommend just buying one.

All the results you have found sound normal:
- Plugging the PCV changes the idle air flow into the manifold and changes the mixture and available air to the engine.
- The pressure build up sounds normal
- The dip in engine sound when inserting the PCV valve sounds like a small change in idle air into the intake

I am not sure you actually have any issue; it just may be a loose hose connection on to the PCV outlet. The hose you have looks to be sized for a larger, PCV port and so it just may be leaking a bit there. No harm, just dirty.
 
gdizzle said:
Hey your comment about Dipstick just rattled something in my brain. Since this oil issue seems to be somewhat new, I did make one adjustment about 2 weeks ago. I have this wrong Oil Dipstick that never seated all the way because of oring seal. I recently took it out and cut off the oring (it was like a 1 inch long tappered seal) so that it now fully seals. Is it possible that it was venting through the dipstick and now that it cant vent there it is forcing more through the PCV and thus misting some oil out of the connection? Seems crazy....right?
Click to expand...

No,the PCV is the vent.
But if your oil level is too high the crank can make a mess in there. And the blowby has to go somewhere and if you put too much oil in there, then there is less room for the gasses to accumulate.
However, from your "goosh" statement, it's clear that your engine is tired.
The rpm difference of PCV in air versus PCV in cover is the difference in combustibility between the two different gasses.
The hesitation should not be hard to work out, if the engine was in good mechanical shape.
 
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nm9stheham said:
If you want to check vacuum, then connect to the port on the #6 intake runner. Vacuum/pressure gagues don't cost much and are good to have for general work so I'd recommend just buying one.

I am mostly retarded, so where is the port on the #6 intake runner? You mean that rubber post that appears to be capped off at the rear of the engine? Is that what that is for?
Click to expand...
 
Why are we checking engine Vacuum, again?

Oh, I see, post #15 , "If you want to see". So for curiosity sake.
Ok then, no you don't have to disconnect anything else.
And I can't help you with a number, cuz A) I'm not familiar with that vintage engine, and B) I'm not that familiar with slantys, and C)most importantly; the number varies wildly with timing,rpm, camming, compression, valve lash,and mechanical condition.I could guess and say 15 to 18 inches; but that would be a guess. A tired slanty might be on the low side of the range;or less.
And that takes us back to "goosh"
I think "goosh" needs a re-visit. With the engine idling, and the PCV correctly installed and sealed and working,; and with no known other crackcase leaks; pop the VC breather off, and put the muscular part of your palm (next to the Thumb),over the hole. The idling engine, after something like 15 or 20 seconds, should be trying to inhale that hand. After 30 seconds to a minute, it should be quite noticeable.
Now, if it should be, that the idling engine, builds up pressure and trys to blow your hand off!, well that's bad and the engine is tired. I think I mighta mentioned that in a previous post.
So what does tired mean? That depends. A compression test is now warranted, and possibly after that, a leakdown test. If the results are in the basement, then tired means worn-out.
 
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The OP said it 'gooshed' with both the breather AND the PCV plugged. It's gonna build some pressure that way; sounds normal. As you suggest, try it with the PCV installed and with the hand over the breather and see if there is some vacuum under the palm of the nad covering the breather.
 
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