Correct breather for cast aluminum valve covers

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Righty Tighty

Righty Tighty

Blame it on the dog
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Am I the only one who can’t find a two port breather that will go deep enough to seat itself in my Mopar Performance valve covers? The hole in my valve cover is at least 1/8” deeper than the stem on the breather. I can’t even find grommets that will go that deep...at least not breather-specific grommets.

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I should specify, the grommet set I bought was perfect for the breather, however the breather and grommet are both much too shallow to seat in the valve cover.
 
diymirage said:
@CudaChick1968

and perhaps we oughta make this a sticky?
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The covers are a half inch thick where the PCV knock out boss is and the manufacturer sadly discontinued the right grommets a few years ago. The ones sold now (not Mopar-specific) have a seating groove/channel that is much too narrow to seat in there properly.

The only one I can find lately for my customers is a set with a traditional PCV grommet and a plug. Unfortunately that grommet's center hole is too small for your big factory breather.
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I bet you could cut the bottom off of the plug with a band saw though. It would be quicker and easier than trying to drill a bigger hole in the grommet.

I don't recall the name of the place where I bought this set but do remember it's in East Moline, Illinois if that helps (I was born in Moline).

I hope this gets you back on the road!
 
CudaChick1968 said:
I hope this gets you back on the road!
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i just figured since you probably see more of these in a week then most of us in a lifetime, you may know the answer

i run the holley ones on my duster, and i honestly dont remember how i made it work
 
CudaChick1968 said:
The covers are a half inch thick where the PCV knock out boss is and the manufacturer sadly discontinued the right grommets a few years ago. The ones sold now (not Mopar-specific) have a seating groove/channel that is much too narrow to seat in there properly.

The only one I can find lately for my customers is a set with a traditional PCV grommet and a plug. Unfortunately that grommet's center hole is too small for your big factory breather.
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I bet you could cut the bottom off of the plug with a band saw though. It would be quicker and easier than trying to drill a bigger hole in the grommet.

I don't recall the name of the place where I bought this set but do remember it's in East Moline, Illinois if that helps (I was born in Moline).

I hope this gets you back on the road!
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Thanks CudaChick. I don’t know what the deal is with mine, but I measured .556 on the cover and .440 on the neck of the breather. Then there’s the beveled lip on the grommet that’s supposed to extend past the boss, so that makes the even smaller. Is there a chance the hole was cut in the wrong position? Like that particular position wasn’t intended for the breather but something else? I noticed the valve cover thickness at the oil cap hole is much thinner than the breather hole.

The ones I got from Mancini Racing looked just like the one you have pictured with the end plugged, so I cut the end to open it up. Since the beveled part didn’t push all the way through to lock it in, I attached some grip tape (like on a skateboard) with RTV and stuck it in. Unfortunately the RTV didn’t work like I’d hoped it would.

I was thinking of doing the same thing, except maybe with Permatex or a bearing mount product. What is the depth of the grommet with the plugged end? I’m hoping it’s deeper than the one I got from Mancini.
 
Don't know if this helps, but im running this one mine

The number cast in is SPC 7211

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Judging by this, it seems you can cut the bottom 5/8" off the plug (to the bottom of the lock swege underneath the groove channel in other words) and it would work. (Excuse the die grinder ... I ran out of hands.)

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The only 1" ID grommet in my stash is the same sized opening. If it wasn't junk I'd just give it to you.

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You're right that the oil cap hole is thinner than the knock out boss by quite a bit.

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I don't know if anyone makes a screw-in nippled breather like yours but, even if they did, then you'd need to plug the opening on the knocked out one. Ackkkk!!

Just cut the bottom off the plug and you should be good to go.
 
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not sure what size the boss it
i can feel it slide home when i pop it in

so, its gotta be less then 1/4 inch thick, im guessing
 
Do you have to run that breather set up? No picture of both covers, but can't you have a breather in the cover that has the oil filler cap and a pcv valve on the other bank?
 
This is my current setup.
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When I went from 2 bbl to 4 bbl, I went to a 2 port breather because the 3rd line (can’t remember what it was for) was lost. I wanted to keep the fuel vent line and breather, and didn’t want the breather to spit gunk all over the cover, so I opted to plug it into the air cleaner.

With both covers having 2 holes, I don’t know what other options I could run besides permanently plugging one.
 
Well, if it was mine, I would plug the so called breather hole. If the one hose is a vent for the fuel tank, find another place?Get a 1/4 lock breather for the cap in the back on the pass side. Surprised I guess that there are 2 holes punched in each valve cover, are there baffles under the pcv valve and the cap on the pass side?

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I have a set of edelbrock covers, and a similar issue. I bought a breather and a grommet off amazon,edelbrock brand. There were various grommets listed.
 
Here is the twist in breather #MOPP4529880. Mancinni Racing, $8.78.
Valve cover grommet set #MRE5249642, $8.95. I have not had any issues with the breather leaking.
Looking back at your last picture, I would buy 2 grommet kits, put plugs in the 2 non baffle positions, breather in front drivers side, pcv valve rear passenger side.
Good luck.

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CRUZE 418 said:
Surprised I guess that there are 2 holes punched in each valve cover, are there baffles under the pcv valve and the cap on the pass side?
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I bought them used on eBay, and that's how they came. In my naivety, I simply didn't question that they had all holes punched out. I will say that once I received them I noticed the hole that the breather is currently in was pretty out of round, and not very well done. That should've been a red flag.

The only baffle is under the PCV valve, all others go straight in. I'm trying to keep the system close to factory - in that the breather, fuel vent, and PCV all go back into the engine. But we'll see what I can come up with. I may just use the boring head on the mill and create a step underneath to reduce the thickness of the boss.

I do like the idea of just the PCV and breather, it's a nice clean look.
 
You can easily make 3 baffles, you have one for a template. I would do that, for all 3. If you have access to machine shop , or a friend that has a lathe and end mill, and has the materials , you can make what you need. Not too difficult to do, would actually be fun, that's unique to customizing. If you should go the way I have, the rubber plugs should conform to your irregular holes. I would still make the baffles. If you have peas, make pea soup, and it will look good when you are done, either way.
 
You’re right, making the baffles would be easy. I have a mill at home, which is how I was going to create the step underneath to reduce the thickness of the boss. I should say that I already bored the irregular hole to make it round again, so that’s not an issue.
 
Then, if you have access to a lathe and some large round stock, make the part for your breather to work, weld or epoxy, or grommets.
 
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