So It appears at higher rpms, say 3500+ my car seems to "spit" oil out of a couple of small pinholes in the intake gasket. Now I've replaced the damned intake gasket three times this summer, learning the hard way not to use end seals.

But before I get too far, when I had the performer RPM manifold on the car, a long highway trip, I would notice oil on the back of the motor, near the distributor, never through too much of it. After replacing it three times(two times with end seals), once with "The Good Stuff", it seemed fine, for several hundred miles. Maybe 700 miles. Then I noticed, on the highway, cruising about 80mph, If i let off the gas, and get back on it, I could smell oil. I have 73 stamped valve covers, one side has the pcv valve going into the big tube on the carb. The other has a breather element routed into the air cleaner base(edelbrock).

If I remove the breather element and rev it up to 3000 rpms, I can see smoke/oilly gas come out of the breather. when this is disconnected, it makes the leak at the intake much easier to see too.

What could be causing the problem? The pcv valve has been replaced, the breather is less than a year old. The intake is new, and the motor is clean, I've had valve covers and intake off, no signs of sludge, not even a little bit.

What could make this happen? Car has 3.33 or 3.23, not sure, single track rear. Stock AFAIK motor(rebuilt, maybe, but not over stock, not a burnout machine :/), TH-350 transmission. At 80ish, I should be around 3500rpms, give or take, well within the limits of the motor. It shouldn't be having issues.

Everything seems fine, just lots of crankcase vent. The valve covers have the stock baffles in them, the long ones that came factory. Also, if I rev past 4000 rpms in park in the driveway for 10 seconds or more while testing, the valve covers will actually weep... Something's wrong...

The only thing I can think of trying is getting one of the those vented oil fill caps, hoping to relieve a little more pressure. Other than that, I'm out of ideas. :/

 

Sounds like excess blowby from poorly seated rings.

 

Too much crankcase pressure, sorry. I've seen enough to actually shoot the dipstick out of the tube before. Do a leak down test and know for shure.

 

If rings were bad, wouldnt the car smoke on idle, or when driving?


Wow, mines not quite that bad, but you're probably right. Time to buy a tester... which leak down tester do you guys recommend?

 

Sound like your engine is on the downhill slide and maybe you need to start driving it a little easier. I have no idea what you have for a car, you have nothing in your statistics.

 

Car is a 1972 Cutlass with an original or stock rebuilt 350, TRH 350 trans, and either 3.23 or 3.33 rear end gears. When I bought the car, there was no breather element on the passenger side valve cover, and only the pcv valve from the drivers side.

I swapped that around, and I thought it fixed the problem, in addition to installing correct valve covers with factory baffles in them.

Would a vented oil fill cap help relieve more pressure, or would it just create a mess under the hood?

I'm looking around for a leak down tester, before I buy one, but is there anything else that could be checked? The car doesn't smoke when running or driving(verified by being followed on the highway, etc). I would think bad rings would tend to smoke?

 

A vented cap won't help. There is no "help" in this case. The only real choice is figure out what's wrong and fix it. There should be blow-by when you're really getting on the engine, but not just idling at 3500 or crusing.
The correct '72 PCV configuration is PCV valve in the driver's cover, with a breather on the passenger that is plumbed to the air cleaner. That way blow-by at WOT is sucked back into the engine.
Bad valve guides/seals will smoke. Really bad rings will smoke. Rings just starting to fail will just have too much blow-by.

 

Maybe we have a difference of opinion on what is considered excess blowby. If it had bad rings it would smoke. If the rings are not that bad you may not see the smoke. The pcv is a "controlled" vacuum leak, if it's too much for that to handle and the valve is not bad then it can only be from crankcase pressure. Is it actually pulling vacuum? Then we have to wonder how old the engine is. What is bad for a new engine may not be considered bad for one with 150k on it.

Checking the leakdown is the only way to know for shure.
[B]Would a vented oil fill cap help relieve more pressure, or would it just create a mess under the hood? [/

Yes and yes.

 

Having been there and done that, as the others have said it's time to start planning for a major repair. If you put a breather on the opposite side of the engine and run a hose to the air cleaner you may be able to postpone the inevitable. The vacuum leak in your intake is not helping either.

 

I had this same problem With My Omega.I chased it for years.The oil wasn,t getting back to the chrank case fast enough and filling up the area under the intake blocking off the ventilation of the crankcase.All I had to do was put a PCV valve in the back of the oil fill tube.It fixed it imeditly.
railguy

 

Sounds almost like a broken ring

The crankcase is supposed to be ventilated by the PCV system- Positive Crankcase Ventilation. With a good vacuum and not much blow-by [normal idle to cruise conditions], air is drawn into the engine thru the breather filter, out the PCV valve, into the intake and burned in the engine. Under low-vacuum hi-blowby conditions such as wide open throttle, excess crankcase vapors are supposed to flow back OUT the PCV filter to the air cleaner, where, again, they are drawn into the engine via the intake system.

 

Not if the holes that the oil drains through are covered.That's what these are for,I wish I had used them.
http://www.jegs.com/i/Moroso/710/25025/10002/-1
railguy
The first time I saw these I thought they were to slow down the oil back to the crankcase.It was'nt till I had this problem I realized what the are for.
railguy

 

Uh, no. If you use those, then you have to add external drain-back from the heads to the pan and from the valley (just in case). The olds block drains back to the pan through the valley only. Those stop that, to prevent windage. One would have to worry about other things, like sufficient cylinder and cam oiling when cutting down windage that much. But that's for race engines, and the guys building those are plenty smart enough to work out a full plan.
I can only assume that the drain problem you had was the drain holes were blocked (old burnt oil common after 150k+ miles) and the oil was so thick that whatever drainage area left managed to get air-locked.

 

I had oil leaks for at least 3 years.When I put the PCV valve in the back of the oil fill tube they stop at that second.Oil leaked everywhere not a lot it was just a few drops but mainly the back of the intake and the valve covers, Oil pan a little but it all stopped when I added the PCV valve to the back oil fill tube.It was the most agravate thing.Ever time I thought I had it fixed I opened the hood there it was again
railguy

 

You don't have to use them all.And I think there is a couple other holes over the cam.Mine is fixed with the Extra PCV valve.
railguy

 

You still haven't told use how many miles are on this engine. I have the felling you are trying to treat a symptom and not the problem.
It won't always have visible smoke out the tail pipe, it may have just enough oil control yet to not smoke out the tail pipe but all that blow by is smoke blowing past the rings into the crankcase and smoking out the tailpipe is not far away.
You are probably going to have to rebuild the engine in the not to distant future or start drive your car like the old lady she is.

You

 

I wouldn't' be too quick to rebuild the engine.If it's not using oil and not lacking on power I'd look in other places first. I think what caused mine to do this is the oil pressure.When the engine is warm I got 80 lbs.Too much oil trying to get back to the pan covers holes which builds up pressure making it even harder for the oil to drain which makes it build even more pressure and so on.
railguy

 

Let's not confuse oil pressure with crankcase pressure. One has nothing to do with the other.

 

Wouldn't a higher oil pressure put more oil up on top of the engine?
railguy

 

No in a cold engine, the oil pressure goes up because the flow goes down. As the engine warms the flow goes up and the pressure goes down.

 

That problem is caused by blowby,combustion pressure passing the piston to cylinder walls.IE wear.

 

Badly seated rings can do this.It might not be as noticable in a mildy driven car,but definitely more noticable at higher rpms,like taking it down the track.You can have this issue without having any smoke.It can blow the breathers out,and if you duct tape those down,it can blow the oil fill tube out,if it's that bad.I've seen it on a fresh engine that did not have the correct finish on the cylinders.

 

You installed a second PCV valve in the back of the oil fill tube? How did you do that? what did it connect to? Do you have any pictures?


The engine is clean, I'll post pictures tomorrow at work, but the heads look clean, the intake area was spotless, I was surprised the first time I took the intake off.

Odometer reads 46,000 miles. Probably 146000 miles, but I'm unsure. I know the car was taken off the frame circa 1996 and rebuilt, I don't know if the motor/transmission were done at that time. I don't think pushing 3500 rpms is driving it hard? I can go WOT in 1-2-3 and it doesn't leak at that point. It only seems to do it on the highway, cruising at 80mph in third, or free-reving in the driveway.

Great... I had originally planned on doing an LS swap last winter, it was going to be a a project between me and the ex. But she's an ex now, and we all know how those things go.

 

Quote:
Originally Posted by Railguy View Post
I had this same problem With My Omega.I chased it for years.The oil wasn,t getting back to the chrank case fast enough and filling up the area under the intake blocking off the ventilation of the crankcase.All I had to do was put a PCV valve in the back of the oil fill tube.It fixed it imeditly.
railguy

You installed a second PCV valve in the back of the oil fill tube? How did you do that? what did it connect to? Do you have any pictures?



Heres a couple pics poor quality I used My phone the batteries were dead in my camera.It may not be the oil pressure that caused it thats what I aways thought.I was under the impression that your motor was rebuilt recently.Image08292013165719.jpg

Image08292013165702.jpg

 

I can't tell what I'm looking at. It looks like a vented oil cap on the fill tube for the motor. What is the red thing in the intake? Is that the pcv valve you're talking about? How is that secured to the intake? Sorry, looked at it for 5 minutes, can't tell what I'm looking at.

If you get a minute to take pictures with the digital camera, my email is jpc647@aol.com. Feel free to email me pictures if that is easier.

 

The red thing on the intake is water temp.It was a vented cap but it's blocked off.I'll charge up the battery tonight.
railguy

 

Are the baffles still under the valve covers? The fact that it does not do it at WOT,leads me away from the bad ring theory,and possibly that the top of your engine is getting excessive oil that can't return fast enough.
At this point,I would make sure all of the PCV parts are good,and you are getting the proper ventilation. Step 1. Check the PCV valves,breathers,and hoses. Even a dried/cracked hose could make a fuss.

 

Quote:
Originally Posted by jpc647 View Post
I can't tell what I'm looking at. It looks like a vented oil cap on the fill tube for the motor. What is the red thing in the intake? Is that the pcv valve you're talking about? How is that secured to the intake? Sorry, looked at it for 5 minutes, can't tell what I'm looking at.

If you get a minute to take pictures with the digital camera, my email is jpc647@aol.com. Feel free to email me pictures if that is easier.
The red thing on the intake is water temp.It was a vented cap but it's blocked off.I'll charge up the battery tonight.
railguy

 

Everything seems okay. All the grommets are new beginning of the season. Baffles are in the valve covers. I think the oil can't drain fast enough too. I wonder if the aftermarket intake valley pan is stopped oil from draining back down.


Thanks for the photos. So you drilled and tapped the side of the oil fill tube and put a pipe fitting style connector on it, with a hose and there is a PCV valve in there as well? And that goes to a "T" fitting which connects to either the other side or can be plumbed into the line going into air cleaner?

 

Thanks for the photos. So you drilled and tapped the side of the oil fill tube and put a pipe fitting style connector on it, with a hose and there is a PCV valve in there as well? And that goes to a "T" fitting which connects to either the other side or can be plumbed into the line going into air cleaner?


I'll send you another pic tomorrow.I know I sound like a broken record, but I chased this problem for years.It stoped as soon as I put the PCV valve in the oil fill tube.FYI I don't use a Valley pan.
railguy

 

Railguy - is there a vent on your passenger side valve cover? PCV system needs a vent somewhere, looks like yours is via the oil fill tube. Stock setup was pcv on drivers side and vent to air cleaner on passenger side.

Assuming jpc has a PCV and vents somewhere, sure sounds like a tired engine developing some blowby. May still last for years as a weekend driver if not pushed too hard. Running a slightly heavier oil may help in the meantime, had an old ford truck that fogged mosquitos with 10W30 but did OK with 10W40

 

I don't know about jcp but My engine was rebuilt 6 or 7 years ago It's only been driven maybe 6,000 to 8,000 miles.It's done it since day one.About 3 or 4 years ago was when I put the extra PCV valve on.Does not smoke in the least.
I Used a PCV valve that has threads on it.I didn't think to mention that earlier.I Just drilled the Oil fill tube and screwed it in with a little permatex.Be sure to re move the tube first.It's a very simple fix and for all it costs worth a try .IMG_3769.jpg

IMG_3771.jpg

IMG_3772.jpg

IMG_3773.jpg

IMG_3770.jpg

 

I'm still confused. I'm sorry. So you took the oil fill neck out, drilled and tapped a hole into it, and then screwed the pcv valve into it. Or did you do it on the vented fill cap? I thought above you mentioned the vented fill cap was blocked off. How'd you do that? Then that goes into the "t" coming from the drivers side valve cover, correct?

The pictures show some sort of extension on the oil pressure switch and it looks like a clear tube with oil in it going somewhere. What is that for?

 

I have the same problem on my 455. Would this work on my engine as well

 

I'm still confused. I'm sorry. So you took the oil fill neck out, drilled and tapped a hole into it, and then screwed the pcv valve into it.

Right,only I didn't tap it the PCV valve just screwed in.I got the PCv valve from an auto parts store Advance auto I think.there was a bunch of them on a rack in the back I just picked one out. The vented fill cap is blocked off"not vented any more" so it doesn't pull air in through it. It looks better than the original one.

Then that goes into the "t" coming from the drivers side valve cover, correct?
Correct.


the vented fill cap was blocked off. How'd you do that?
I forget I'll look and send you a pic.


The pictures show some sort of extension on the oil pressure switch and it looks like a clear tube with oil in it going somewhere. What is that for?

That's for the oil pressure gauge I needed the extension in order for the adapter turn in cause I wanted the idiot light to work to.

 

Like I said before for what it cost and as easy as it is ,It's worth a try.Assuming you're having the same problem.
railguy

 

How does the pcv valve screw in if there are no treads for it to screw into? Aren't most PCV valves flat or non threaded on the body?

Is this a stupid question? Can someone explain this to me?

 

I've seen this done in the past:

 

Jmho but this is the the only logical explanation. Everything else is just working around the problem. I would perform the leak down test and then you will know for sure. Oil drain back due to plugged oil passages makes no sense to me. How much oil would it take to fill the intake valley to leak out of the intake? Wouldn't be anything left in the pan! However, I do believe the extra PVC valve would disguise the symptoms of poorly sealing rings. If your only consideration is to eliminate the oil blow by, then the extra PVC is a good option. If you are concerned with the amount of power you lose with poorly seating rings then I would do the leak down test. Let us know how this works out.

 

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