Pushing oil out the breather, need better crankcase vent system

[1danc]

Definitely need mitigation, and I'm not able to check the engine for you - I would believe that there is another issue you should run tests to find - glad it seems OK, too much pressure ! Oil seals leaking coming next , pull the plugs and do a compression test @ a minimum - possible head gasket damage near oil feed ? Hope the best for you ✌

 

[Paul_G]

I rebuilt an engine two years ago that was pushing oil via the breather into the air cleaner. About 6 of the 8 top rings were broken when it was disassembled.

That sucks. What did you do to damage that engine, what hurt it?

 

[Geoff 2]

Not my engine. Brought to me for rebuild because of the oil problem.

 

[Stumper]

I read today that they are designed to work with an exhaust without mufflers. Is that true?

It had just a pcv, no breather when it balloned that pan. I have added a breather since. Just now getting to replacing the valley pan.

 

[505Coronet]

Sounds real similar to mine, installed an evac kit like what was posted and no issues since. Lost of spirited throttle usage since as well. I run a straight through muffler so no issues pulling vacuum. I posted a thread in the racers forum that came to about the same conclusion.

funny to see the same people posting that they want a full tear down of an otherwise happy engine...….

Different strokes for different folks i guess

 

[Paul_G]

I just reread the post. I neglected to state earlier in this thread that the valley pan was cracked under the intake as well as ballooned. Did not see the crack till I pulled the intake off. Oil was not excessively coming out of the breather, it was excessively coming out the valley pan crack. So I highly doubt there is any need to tear down an engine that runs very well, does not leak, and has 8 clean spark plugs. Maybe some people just like tearing down perfectly good engines?

 

[Geoff 2]

' Perfectly good' engines do not crack valley pans......

 

[Paul_G]

And your an engine builder? Just had some fun with the car, spirited driving in to triple digits, revs to 6000 RPM. No smoke, no stumbles, and no more oil leaks. The new valley pan is unharmed. And you still think this engine is hurt?

 

[1danc]

Too weird for me, I'm out - Good Luck Brother

 

[RemCharger]

And your an engine builder? Just had some fun with the car, spirited driving in to triple digits, revs to 6000 RPM. No smoke, no stumbles, and no more oil leaks. The new valley pan is unharmed. And you still think this engine is hurt?

You're fairly correct. If you drive it enough and there's no oil usage or plug fouling, can you really say there's an issue .
A leak down would identify " cracked rings" but so would the previous comment.
It's all in the interpretation of engine performance.

 

[Rishi]

I vote let him be. Live and let live. Asking for opinions doesn't mean he has to follow advice. If there IS a cracked ring and engine issue, it will rear its ugly head soon enough.

 

[dvw]

So you think a deformed valley pan is 'normal' for a high performance engine?

I rebuilt an engine two years ago that was pushing oil via the breather into the air cleaner. About 6 of the 8 top rings were broken when it was disassembled.

It would be with no breather. No way a PCV with no breather would vent much if any pressure.
Did anybody read post #14?
{quote}
Been driving it the last few days with no issue. PCV in right valve cover, breather in left valve cover. So far no issues. I think the problem was not having a breather in at least one valve cover.
Doug

 

[vance.dykes]

try this

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[beanhead]

Before you all start throwing fisticuffs I think there's just been a little confusion....

The 505 makes good power, never been dynoed but pulls like a freight train. I only have oil out the breather after some spirited full throttle fun. Crank case pressure can get pretty high, the tell is my valley pan has been pushed up to the bottom of the intake and finally cracked, making an oily mess. Replacing the valley pan right now, but need to do something to relieve that pressure.

It has a PCV valve in the left valve cover, and a breather in the right valve cover, the breather leaves oily residue on the valve cover.

What are some options to fix this?

I read today that they are designed to work with an exhaust without mufflers. Is that true?

It had just a pcv, no breather when it balloned that pan. I have added a breather since. Just now getting to replacing the valley pan

There is no real problem. It is a high performance engine. I failed to put a breather on it, it built pressure in the crankcase at high RPM exceeding the ability of the PCV Valve to manage, it has to go somewhere, leaving it with no where to go it ballooned the valley pan. Adding the breather solved the problem. Can any ICE function without crank case pressure mitigation?

Sounds like it's fixed...that's a good thing! Pushing oil sucks.

 

[Geoff 2]

Some apparently do not understand the function of the breather. And why the breather is spaced away from the PCV [ on opposite valve covers on a V8 ]. The breather is for air to enter the engine, not breathe out. [ If the breather was there to breath out why would it need a filter in it???? ]. The breather placement allows clean outside air to be drawn through the engine, taking blow-by vapours with it, passing through the PCV, to be burned in the engine.
The valley pan bent upwards because of excessive internal pressure build up inside the engine.

 

[beanhead]

Some apparently do not understand the function of the breather. And why the breather is spaced away from the PCV [ on opposite valve covers on a V8 ]. The breather is for air to enter the engine, not breathe out. [ If the breather was there to breath out why would it need a filter in it???? ]. The breather placement allows clean outside air to be drawn through the engine, taking blow-by vapours with it, passing through the PCV, to be burned in the engine.
The valley pan bent upwards because of excessive internal pressure build up inside the engine.

And who would you be referring to exactly, Mr. "throw your Holleys in the trash" guy?

 

[Geoff 2]

The guys that think the breather is there to breath out.

 

[dvw]

There isn't an engine that doesn't produce some positive crankase pressure. How much? That depends on the breather restiction and amount of flow. Flow measured in CFM is the real indicator of ring seal. That being said crankcase design, larger engine displacement, boost all will increase this CFM. Even if the ring seal is very good. Without at least some type of breather with enough flow capacity that exceeds the blowby CFM, you will see the results as posted in Post #1. A PCV under full throttle does nothing. engine vacuum is maybe 1.5HG at best. So blowby flow will always exceed pcv flow. The goal for every engine is to keep blowby at a minimum. Thats why you see vacuum pumps. Vacuum pump (and dry sump with scavange) use no breather system. The idea is to create a negative number in the crankcase. But lets face it normal street/strip stuff doesn't have ring seal like formula 1, Nascar, Pro Stock. better ring seal is worth power for sure. But I'll bet if you took a blow by meter to your local racetrack there would be many engines with way more CFM flow than is considered "normal".
Doug

 

[HEMI-ITIS]

I don't care for PVC systems in performance engines. Any oil that can get into the PVC feeding the carb will detonate and that is not good.I use 2 catch cans with breathers on them coming off the valve cover.

Moroso 85751: Oil Breather Tank -12 AN Fitting - JEGS

 

[beanhead]

The guys that think the breather is there to breath out.

Okay, I hear you....though the breather can act as a pressure release at WOT I understand what you were saying, that isn't it's primary function.
Things definitely do need to be in good order in the first place. Not having a breather is like trying to inhale with your nose pinched. Then try to exhale...pop goes the eardrum!

I don't care for PVC systems in performance engines. Any oil that can get into the PVC feeding the carb will detonate and that is not good.I use 2 catch cans with breathers on them coming off the valve cover.

Moroso 85751: Oil Breather Tank -12 AN Fitting - JEGS

Since I still wanted to run a PCV I installed this simpler separator version. Even with good baffles and healthy rings my PCV was sucking some of the oil that flies around inside the valve cover. It's working well, I periodically empty it and there's usually a couple of tablespoons worth in there.
Moroso 85496 Moroso PCV Air/Oil Separators | Summit Racing