Pushing oil out the breather, need better crankcase vent system

[Paul_G]

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?

 

[pnora]

Might have a ring sealing problem. Leak down test would tell you more. Options evac kit with check valves into the collectors. Vacuum pump system with catch can.

 

[Paul_G]

The engine only has 6000 miles on it. Ring gaps were set a little on the wide side, .028". Spark plugs dont show any signs of oil residue.

 

[Paul_G]

I was thinking of using a catch can mounted high on the firewall. Put a breather in the valve cover that has a fitting to attach a hose, run the hose up to the inlet of the catch can, let the outlet of the can vent to atmosphere. Dont know if a catch can will work that way? Usually the PCV pulls through the catch can, my idea would have pressure push through it.

 

[pnora]

There are lots of things you can try. Thing is are you covering for a problem? Thats why I suggested a leak down test. It this one of your blow through engines?

 

[Paul_G]

Not this one. It is naturally aspirated 505 Stroker.

 

[toolmanmike]

The PCV system uses vacuum from the carb to work. Under hard acceleration there isn't much suction and especially if you have a hot cam. The race engines use a Vac U Pan system where the exhaust going through the headers provides the vacuum.

 

[R413]

Ballooning the valley pan isn’t a good sign.
first thing is try a leak down test.

 

[Paul_G]

The PCV system uses vacuum from the carb to work. Under hard acceleration there isn't much suction and especially if you have a hot cam. The race engines use a Vac U Pan system where the exhaust going through the headers provides the vacuum.

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

Ballooning the valley pan isn’t a good sign.
first thing is try a leak down test.

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.

 

[RemCharger]

You can use them with exhaust, but need to run the hoses close to the exhaust outlet

 

[Geoff 2]

The fix is to pull the engine apart & fix the blowby problem. You may have broken rings.

 

[BSB67]

Just put it back together correctly with a pcv and a breather.

If it ballon’s the pan again, find your problem and fix it.

 

[1danc]

Definitely need to find / fix the cause of excessive pressure - either your complete pcv system was failing : clogged pcv/hose/no vacuum on the hose or breather not letting air in ? You need to find the root problem B4 it can be fixed ! I always run exhaust vacuum valves in my header collectors / always with mufflers - even a stock New Yorker I drove around w/110K miles on it didn't build pressure to that

 

[Paul_G]

Just put it back together correctly with a pcv and a breather.

If it ballon’s the pan again, find your problem and fix it.

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.

 

[Orig69]

In post 1 you said
"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."

In post 14 you said
"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."

 

[Paul_G]

Dyslexia?

 

[GTXDAN]

Here's a good fix. Summit racing.

Allstar Performance Crankcase Evacuation Systems ALL34145​

Part Number: AAF-ALL34145

$47.99
Allstar Performance Crankcase Evacuation Systems
Crankcase Evacuation System, Steel, Chrome/Gold Iridited, Universal, Kit
See More Specifications


In Stock (more than 10 available)

 

[Geoff 2]

All these 'fixes'....but none that address the real problem.

 

[Paul_G]

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?

 

[Geoff 2]

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.