Blowing outof oil fill hole, 196, Scout 800

[Ruper]

Hey everyone, back to dealing with my blowby issues.

Ok been running my Scout for a while mainly weekends, had just put a supposed factory rebuilt 196, in the '66 Scout 800, manual trans, Holley/weber 5200, petronics ignition stock type.
The truck runs great especially after getting the carb dialed in and jetted.
However I noticed some tim ago that pressure is coming out of the oil fill cap in the valve cover. Checked and double checked all pcv routing, and anything else I could thnk of, I have a little experience with IH engines, however I am stumped, I can't get this to stop. When you put your hand over as is near to the hole when open you feel pulses over air coming out as if a valve is open. Took valve cover off check everything there, adjusted the "retorqued", checked valve open close. Compression is the same in all 4 cylinders. No smoke, no excessive fuel burning, plugs look good, nothing seem out of order.
Where is this coming from?

Any help would be great!

 

[Michael Mayben]

We need to see pictures of your exact pcv routing including which pcv valve ya have.

Pics need to show all vacuum connections on the intake side of the engine, including the carb connections and distributor.

Need pics of the fresh air air cleaner connection also if you have this set up as a "closed" type pcv system.

Anything else at this point is pure speculation and beerthirty talk.

 

[Ruper]

Here are pictures, tappet cover fitting through, spark arrestor, into manifold, fitting in mani also has vacuum wipers on it. I have cleaned the spark arrestor and checked function, and it flows from crankcase to vacuum manifold

flow through air filter, into valve cover through cleanable cranck case filter, not a pcv or check valve.

 

[Michael Mayben]

Good pics, but you have your labeling mis-represented.

The flame arrestor component is mounted in the valve cover, that is a simple canister containing wire mesh and is not a check valve of any sort. And in a "closed"-type pcv system that is the fresh air source (pulled through the clean side of the air filter assembly) that allows clean/filtered air to enter the inside of the engine.

The device you have labeled as "spark arrestor" is a "cleanable" ac sparkplug p/n cv 619 pcv valve. See this thread:

http://www.forums.IHPartsAmerica.com/gas-engine-tech/2244-servicing-cleanable-pcv-valve.html

Most likely it is installed backwards. It is a one-way valve that functions as a "metered" vacuum leak under certain manifold vacuum conditions.

One end of that pcv has a threaded nipple that is one-piece with the body. That end must go to the manifold vacuum source on the intake manifold. The other end has a pipe nipple screwed in..that side must be connected to the fitting on lifter chamber cover.

If the pcv valve is not plumbed correctly, the crankcase is being pressurized and can't "breathe through the pcv system...thus the oil liquid/vapor blowout from the filler cap area.

If the pcv is plumbed correctly on your engine, then it's most likely clogged and prevents proper pcv operation...clean it!

To check proper flow direction for the pcv valve, it should allow flow in only one direction...it is a one-way check valve with a calibrated balance spring.

 

[Ruper]

Ok, I have it all hooked up right. I had cleaned the pcv, but maybe didn't get the hole and set done. Didn't pull it apart but I will today. Looked at the post you put in here. So I will do that today, after I set my tq on the Scout II.

Didn't realize the process was in the manual, thanks for that also.

 

[Michael Mayben]

ok, I have it all hooked up right. I had cleaned the pcv, but maybe didn't get the hole and set done. Didn't pull it apart but I will today. Looked at the post you put in here. So I will do that today, after I set my tq on the Scout II.

Didn't realize the process was in the manual, thanks for that also.

With the engine running at curb idle speed, if ya disconnect the hose from the lifter chamber cover, you should feel a vacuum...that indicates that at least the pcv valve allows flow the proper direction.

The combination of the small bypass hole and the spring is what determines the "action" of the pcv valve when in actual operation.

 

[Michael Mayben]

I should have posted this sooner...this is an explanation of the "closed" pcv taken from the Scout II service manual. The illustrations are exactly the same as the guts of the cleanable pcv valve we are discussing.