valve cover leak

Hello All:

Well the wifes remodle is near done so I have permission to continue my jeep thing YAAA.

Haveing trouble keeping a tight valve cover,,,, have reset it a couple times,,,,, here is my question. I only have the PCV valve comming off the rear of the cover on the 258, I plugged the forward line that went to the air breather intake. will that cause excessive pressure in the engine and therefore compramise the seal at the valve cover or should the PCV valve be adequate to ventilate the engine.

THX
DAve

 

Steel valve cover? Aluminum? Plastic? Year of the engine? Year of the Jeep?

Yes, but negative pressure.

The PCV valve only sucks on the crankcase. You need a source of clean air. You cannot have one connection without the other.

Whether this is causing your leaks, I do not know. Every one of your posts has to contain year, model, equipment information to get a helpful answer.

If you have a steel valve cover, tightening it typically makes it leak more.

 

The steel covers will deform if the gasket is crushed beneath it. Take it off and flatten it with a hammer and some sort of flat steel. buy a new gasket and re install. tighter will just crush it and the same problem will occur. If you really cannot get it to seal, use a bit of silicone. Thats not the right way to fix it, but it might work. make sure your PCV has an air supply or its just not going to work.

 

1974 cj I258, original steel cover, when installing-put adhesive to keep gasket in place then rtv on block- set cover in place and tightened loosly, waited for rtv to set then snugged down not to warp cover as i am aware of that problem.
47v6,,, so when you say an air supply if you mean vaccum connection, yes it is connecetd at the vaccum inlet on the clifford manifold.

My thought was that the pcv was not sufficient to eliminate pressure build up in the top end and the leak was forced. does that sound logical. the vent that comes off the valve cover directly behind the oil fill cap and connected to the air filter intake arm is the one I sealed up.

 

Seems very unlikely.

If you have LOTS of blow-by, oil droplets will come up the air filter connection and put oil into the air cleaner. But that probably happens only when manifold vacuum is low and the PCV valve closes. Manifold vacuum is typically way more than any crankcase pressure.

Air enters the crankcase through the air filter connection, and exits via the PCV valve. You need both an inlet and an outlet (PCV) for it to be connected properly. Why did you remove the air filter connection? It's not a "vent" to vent cranckcase gases - it's an AIR INLET, letting air IN.

 

I put the weber 38dgas on a clifford manifold to get rid of the exhaust/intake manifold connection that was stock. the weber air filter did not accommodate the (air inlet hose) so
sealed it off. Sounds like I will now figure something out to get it back in play.

I am thinking of building my own adapter and mounting the original carter single barrel on the clifford intake. then the air filter system will fit up and I am thinking mileage will be better

what say you Tim

 

You can find a mid to late 70's fiat 131 air cleaner. It will bolt on the webber and have the breather inlet.

 

Just put one of the bling chrome filters in the valve cover. I've seen them at AutoZone. http://www.summitracing.com/search/part-type/valve-cover-breathers

 

Roger, I like the sound of the fiat air cleaner, if that is a pain to find I will try the other
THX