Valve Cover Snorkles

I'm getting a LOT of ail in my airbox on a brand new engine for a 89 4.0L. It has all new everything including the emission lines. Oil is coming in to the point that I go through 1/2 quart of oil if I drive it hard on the freeway for 300-400 miles.

I belive I've tracked it down to the snorkles in the valve cover. When we built the 2 engines for our rigs, we were working with 3 engines and in the process got the snorkles mixed up and didn't realize there was a difference in design. I have two kinds of snorkles: one that's just a straight, shaped tube, and one that's identical except that it has a ~5/16" hole near the bottom of the tube in it.

I'm not sure if the snorkle with the added hole was to be used in both locations, just the front, or just the back. FSM shows no details and searches here didn't get that detail. As well, I'm wondering if the ones with the holes were a later design improvement and if I should use ones with holes in both locations.

Vent system seems to be A-OK and definately good vacuum.

The only other possibility is the "orifice" or rubber grommet at the back of the valve cover. When I bought my new tube set, I was given the choice of a 2.5 mm or 5 mm orifice. I got both and istalled the 2.5 mm version, since the FSM emissions diagram had "2.5" next to the grommet in the diagram.

Obviously, being a hobbyist, I'm not privy to all the tech bulletins in later years, so I'm wondering if someone can shed some light on this arcane and apparently undocumented subject.

Also looking for other ideas why I'm getting so much oil in the airbox with in essence a whole new engine and emission components.

Oil in the airbox is caused by blowby. In other words, worn piston rings. While setting up the scavenging system differently helps, it only covers up the underlying problem, a worn out motor.

Nevada City Sparky said:

on a brand new engine for a 89 4.0L.

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have the rings seated yet?

If the engine is brand new, apparently they have not seated. I've seen this when people try to break in an engine on synthetic oils.

Well, the plot thickens....

What I thought was a cracked flex plate turns out to be something deeper inside the motor. I'm suspecting collapsed lifters or camshaft. This IS a brand new engine with about 3000 miles.

So, does anyone have any insight into the holes vs. no-holes valve cover snorkels?

http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=257836 That has pictures of the snorkles. Mine looked just like those but I have a '91 thus and HO.

Lew360 said:

http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=257836 That has pictures of the snorkles. Mine looked just like those but I have a '91 thus and HO.

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Yeah, seen that post, but it doesn't show the area where the holes are in the side of the snorkle.

By snorkels do you mean the PCV and CCV tubes, fittings, and grommets or are you referring to the ARB intake snorkel or Safari intake snorkel?

BlackJax said:

By snorkels do you mean the PCV and CCV tubes, fittings, and grommets or are you referring to the ARB intake snorkel or Safari intake snorkel?

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I'm talking about the metal snorkles inside the valve cover, under the large airbox hose and the PCV grommet. There appers to be two different styles: one with, and one without a hole in the side of the snorkle. I'm trying to find out where each type is used.

I think the Renix motors used the no hole design and the 91 and later used the hole design. 5-90 seems to be the resident Renix expert maybe he will chime in soon. You could PM him as well.

i'm still not clear on the status of the engine. Is it new or rebuilt? or is it simply a swap? It makes a BIG difference because it could be simply rings not yet seated regardless of what oil you are using, a new engine and rings will blowby at least some. clear up that matter please. if your engine is not "new" and couldn't be unseated rings causing the blowby, then remove your valve cover and clean the snorkels and their splash guards and that should relieve your blowby problem...

avnsteve said:

i'm still not clear on the status of the engine. Is it new or rebuilt? or is it simply a swap? It makes a BIG difference because it could be simply rings not yet seated regardless of what oil you are using, a new engine and rings will blowby at least some. clear up that matter please. if your engine is not "new" and couldn't be unseated rings causing the blowby, then remove your valve cover and clean the snorkels and their splash guards and that should relieve your blowby problem...

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Did you not read my first sentence? I said EVERYTHING is new, including rebuilt engine from reputable local shop. Oil blowby is one issue being addresssed now (shop is determining wrist pin, rings not seating, lifter flat, etc.), but B4 closing up the valve cover, wanted to get the skinny on the snorkles.

Nevada City Sparky said:

Did you not read my first sentence? I said EVERYTHING is new, including rebuilt engine from reputable local shop. Oil blowby is one issue being addresssed now (shop is determining wrist pin, rings not seating, lifter flat, etc.), but B4 closing up the valve cover, wanted to get the skinny on the snorkles.

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yes i read the first sentence, when you typed "new engine for a 89 4.0L" it confused me, sorry, just wanted to be clear. calm yourself, if it's all new, then it would not necessarily be the snorkels, unless your reputable shop just didn't clean them during the build.