breather on the valve cover

[escobar]

Well by looking around online and calling my dad (old school mechanic), I'm beginning to see that the pcv is ran to either the manifold or vac port, or air intake. Old ones ran free to the atmosphere.

It so happens that my various projects have all been to the intake housing and I just verified them by looking under the hoods or manuals for the ones that are gone. Just plain coincidence.

Apparently the AMC 258 i6 / 4.2l goes both ways, depending on year. According to my dad, this means that I can change the pcv flutter 'weight' depending on where I run it. I think he said heavy valve weight for vacuum, and lighter for lines ran to intake filter housings. I cored mine and ran it down the block but I'm going to the parts house to get a new pcv for vacuum set ups.

 

[Rescue Diver]

Well by looking around online and calling my dad (old school mechanic), I'm beginning to see that the pcv is ran to either the manifold or vac port, or air intake. Old ones ran free to the atmosphere.

It so happens that my various projects have all been to the intake housing and I just verified them by looking under the hoods or manuals for the ones that are gone. Just plain coincidence.

Apparently the AMC 258 i6 / 4.2l goes both ways, depending on year. According to my dad, this means that I can change the pcv flutter 'weight' depending on where I run it. I think he said heavy valve weight for vacuum, and lighter for lines ran to intake filter housings. I cored mine and ran it down the block but I'm going to the parts house to get a new pcv for vacuum set ups.

Glad you got it figured out.

 

[escobar]

Well, I've found the correct way to run the pcv on this motor, but even when the pcv was run straight to vacuum the breather leaked. I gotta find a way around this. I'm beginning to think its leaking at the valve cover seal, not the breather filter itself. Need to find another rubber boot now. I wonder if auto zone sells em'.

Thank a lot for your help guys.

 

[Rescue Diver]

Well, I've found the correct way to run the pcv on this motor, but even when the pcv was run straight to vacuum the breather leaked. I gotta find a way around this. I'm beginning to think its leaking at the valve cover seal, not the breather filter itself. Need to find another rubber boot now. I wonder if auto zone sells em'.

Thank a lot for your help guys.

O'Reilly has a good assortment of PCV and Breather Gromets in their Help section.

Like I said before, I would get a push in oil breather that vents through a tube to your air cleaner. As long as it pushes in tight, it should keep your valve cover clean.

Your stock air cleaner will have a place for it, and most aftermarket air filters come with an adapter to drill a hole and screw it on for attaching a hose, or they have one already built in like the new Edelbrock filter I just bought from Summitracing.com.

 

[Tommy]

I have an '81 CJ5 with the AMC 258 i6 / 4.2l . It is smog legal in California and I will describe the set up. The valve cover has three openings. Up front is the oil filler hole. 2 inches behind that is the PCV Valve. It has two vacuum lines running to it. The large line goes to the base of the carburetor just above the intake manifold. The second, smaller line goes to the vapor storage canister on the driver side. I am assuming this is the secondary purge line for the charcoal canister. At the rear of the valve cover is another hole that has a hose running from it to the air cleaner. We do a complete smog check every two years here in California which includes an equipment check to make sure all the lines go where they are suppose to and all the equipment is there and functioning properly.

I eliminated my valve cover oil leak by using "The Right Stuff" yes, that's the name of it. Don't need a gasket, this stuff is truly amazing. I have a lot of blow by, which caused quite an oil leak from the valve cover. This cleared that problem up and what I thought was a rear main seal leak, wasn't.

Blow by continues to be a problem but as long as I keep the revs down it runs fine. Sustained revs over 2500 rpm will spit out the dip stick and gush oil everywhere at an alarming rate. I can run on the highway at 62 mph taching 2100 rpm so I am good there. I put in a T-18 with granny gears so I can crawl over the tough stuff without having to get into it. I guess if I was a mudder I would be in trouble.

Hope this helps.

Tommy

 

[escobar]

I'm going there now.

My air filter housing is one of those quickie cheap 7" or 8" chrome models. No room for drilling or hoses anywhere. I'll look for a new boot/gromet at a.z. and see what I can do. I'm thinking this:

New pcv with proper wt. to vacuum, new gromet and reuse breather if it fits or new breather. If it still leaks then a hose from the gromet to a new air filter assembly.

That's just the thing about these projects, you gotta fix what's important first but within a budget. Its like a big chess game of fix but save.

But you know what- If I was a millionaire I wouldn't buy a finished frame up. I love this game of chess.

 

[Rescue Diver]

As luck would have it, I'm at the point of my head swap project where I needed to address my valve cover ventilation. I went to Oreilly and found a pair of grommets that fit the large 1-1/2" holes in the 1995 4.0 valve cover. One has a 1" inside diameter to work with the Mr. Gasket oil breather that has a vent tube so I can run the hose to the air breather. The other grommet has a smaller inside diameter for the 1974 Monte Carlo PCV valve I went with.

O'Reilly has a good assortment of grommets, so you might be able to find some that match your valve cover holes.