Oil blowing out of beather

[OLD 9]

I got my Jeep about a year 1/2 ago. The 360 has a fresh rebuild on it from the previous owner. Intake is an Edelbrock Preformer and has never been removed by me. It has always blown oil out of the breather and thrown it across the intake. I've changed the PVC hoping that would fix it but no. Thought it may have some rings in upside down but it dosen't burn oil, just blows it out the breather. This is my first AMC motor and today as I was reading threw some posts I got wondering if maybe there is a baffle or something under the intake that may be missing. Is there something that the PO didn't install that may cause this?

 

[Jimbos76cj]

Normally the oil blowing out the breather is from a improperly working PVC system.. Or when the rings are worn and pressure is building up in the crank case faster then the vacuum from the PVC system can get rid of it. The breather really should just be letting clean air in. Where does your PVC valve get its vacuum from?

 

[OLD 9]

PCV valve is in the back of the intake manifold and attaches with a 3/8 hose to the vacuum port on the rear of the carb.

 

[Jimbos76cj]

If you remove the PVC valve is there vacuum on the 3/8" line?

You could try don g a compression and leak down test on the cylinders to make sure they are all sealing right. Where is you breather hooked up to? Is it still on top the tall tube?

 

[xena1]

PCV valve is in the back of the intake manifold and attaches with a 3/8 hose to the vacuum port on the rear of the carb.

Don't know what carb you are using, but there doesn't need to be much vacuum on the PCV valve to operate. I would check to make sure hose is not blocked or not on a vacuum port. Edelbrock carbs have port on the front of the carb. I got too much vacuum from the carb port and re-routed PCV valve hose to bottom of air cleaner and then put an aftermarket breather on oil fill cap plug, or in other words, just made it an open breather. That set-up worked great.

 

[OLD 9]

The wierd thing is that the PCV seems to be OK and I'm not getting any oil smoke out of the exhaust. The plugs are a nice gray color. There is PLENTY of power from the little 360 and no obvious problems other than oil blown across the intake and air cleaner element. PVC fits into a grommet in the back of the intake (Preformer) and attaches to a vacuum fitting on the back of the Edelbrock carb. Breather is a tall tube on the front of the intake with an open bottom type push in cap. Bad time of day for pictures but........

 

[IrishCJ6]

Looks very similar to my setup on my 360 however, I found the sponge/gauze in the breather at the oil filler tube was blocked and was not venting properly, I ditched mine and just put a simple crankcase breather filter on the outlet side of the old breather cap. (my cap is slightly different to yours, mine is plastic with a outlet tube that would have originally gone to the airfilter via a tube, I believe it's a genuine AMC V8 one?) The other thing I have done is ditch the PCV valve setup at the back and have blocked the vacuum port on the carb and just run another crankcase breather filter on the original hose from the PCV but have mounted that to the firewall out of the way. My problem wasn't with oil blowing out of the engine but more engine oil usage, doing this and changing the stem seals solved my problem.

 

[csuengr]

The most common PCV issue on AMC V8's is leaking intake manifold end seals. If the rubber seals provided in the gasket kit were used, you are almost guaranteed to have a leak. The first hing to do when you get an intake gasket kit is put the end seals in the trash. Use a bead of RTV instead.

 

[Ghostship]

If you haven't solved this problem yet... I see you mentioned the PO installed an Edelbrock intake. This manifold requires re-using the lifter valley heat shield from the stock intake, whose sole purpose is to block oil from being sucked thru the PVC. Sometimes this step is overlooked. You might want to pull your intake to make sure.

 

[CJim7]

If you haven't solved this problem yet... I see you mentioned the PO installed an Edelbrock intake. This manifold requires re-using the lifter valley heat shield from the stock intake, whose sole purpose is to block oil from being sucked thru the PVC. Sometimes this step is overlooked. You might want to pull your intake to make sure.

Just to clarify...do NOT re-use a valley pan. These are a one-time only install (like any gasket). be sure to purchase a new one.
But I agree, the valley pan needs to be there, it keeps oil from splashing up on the manifold.

 

[Ghostship]

The valley pan heat shield is not a gasket, it is a shield. The Edelbrock instructions clearly state it needs to be removed from the OEM intake and re-installed, and the screws to do so are supplied. The installation also requires a (new never before used) valley pan gasket. Some people confuse the two, thinking they are the same, and wind up only installing the gasket. Then, they begin experiencing excessive oil thru the PVC and convince themselves they need a rebuild. I've even heard of people swapping engines or selling jeeps because of it, when the only problem was failing to re-use the heat shield.

 

[CJim7]

The valley pan heat shield is not a gasket, it is a shield. The Edelbrock instructions clearly state it needs to be removed from the OEM intake and re-installed, and the screws to do so are supplied. The installation also requires a (new never before used) valley pan gasket. Some people confuse the two, thinking they are the same, and wind up only installing the gasket. Then, they begin experiencing excessive oil thru the PVC and convince themselves they need a rebuild. I've even heard of people swapping engines or selling jeeps because of it, when the only problem was failing to re-use the heat shield.

Correct. I wanted to stress the importance of not re-installing an used valley pan.