MP valve covers knock out machined for pcv grommet (Chevy style)

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skep419

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I was going to use two breathers and a pcv. Knocked it out and quickly found out there isn’t a grommet made that will fit. Brought it to my local engine shop and he knocked it outside of the park.

He machined both the top and the bottom so a standard grommet would fit. It's roughly 1/2" deep and a little over 1" wide to start with. (after the knock out is knocked out)


8829032E-3ED0-4699-8897-1F934BAA76F6.jpeg
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gotcha
what you really want to show off is the part that is hidden by the grommet
why dont you take it out and snap a few pics of the machined surface?
 
And don't forget to install the baffle under the pcv valve. It prevents oil from getting sucked up into the valve.
 
I believe this is what would have worked for you if the breather (or whatever) requires a 3/4" hole. I have personally confirmed this on my own MP cast valve covers - perfect fit (replacing the MP PCV grommet):

Ford Performance Parts Valve Cover Grommet Sets M-6892-F

fms-m-6892-f_w_ml.jpg


My photo below. MP and Ford grommets are dimensionally the same except for center hole:

1-2-Mopar-and-3-4-Ford-grommets-Ford-Performance-Parts-M-6892-F-20184423305165.jpg


Nice machine work, though!
 
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I have a 360 with this type of valve cover. I also drilled out the "knock out" and installed a grommet and the PCV. Despite putting the baffle under the PCV, I continue to get oil into the PCV, which is causing pre ignition knock. Anybody out there come up with a better way to prevent this? Thanks.
 
Thanks, I guess that would work. Looks like you just twist the bottom off it periodically and pour it out.

I'd really rather just come up with a better baffle design since it's strictly a street engine.
 
I've wondered if there wasn't a better solution for a long time too, but what could you put in there that wouldn't most likely come out and end up in your oil?
 
One variable in this equation is the distance of the baffle from the PCV. Right? Or are we sucking up vaporized oil? If we increase the distance of the baffle from the PCV without infringing on the rocker arms, wouldn't that help?

If we're dealing with vaporized oil, the catch can might be the only solution. Never had a problem with any of my SBC's.
 
Oil pull-through from PCV systems is still a problem with some new cars even (modern Hemi cars for instance), one of the first upgrades owners of G3 Hemi-powered vehicles do is install an oil catch can in the PCV line. You can try to add more baffles and filters and such but the PCV will always still draw in a little oil vapor unless it's completely separated out.
 
One variable in this equation is the distance of the baffle from the PCV. Right? Or are we sucking up vaporized oil? If we increase the distance of the baffle from the PCV without infringing on the rocker arms, wouldn't that help?

If we're dealing with vaporized oil, the catch can might be the only solution. Never had a problem with any of my SBC's.
that was one of the reasons I thought it would be better to counterbore the inside of the v. cover , to place the PCV higher in the v. cover & further away from oil slinging around, and futher away from the baffle. Perhaps, a better baffle design would help, too.
of course the PCV location is usually opposite the vent in the other cover: ie. if the vent is in the front left of engine, then the PCV should be right rear of engine.
 
that was one of the reasons I thought it would be better to counterbore the inside of the v. cover , to place the PCV higher in the v. cover & further away from oil slinging around, and futher away from the baffle. Perhaps, a better baffle design would help, too.
of course the PCV location is usually opposite the vent in the other cover: ie. if the vent is in the front left of engine, then the PCV should be right rear of engine.

Good thinking. My breather is exactly as you described....yet I still pick up oil.
 
I installed the Catch Can today. I have a baffle 3/4" below my PCV, so anything I'm picking up is vaporized mostly. After driving about 20 miles and "getting on it" 3 or 4 times, I pulled the canister off and there was a small puddle of oil in the bottom. This engine has about 800 miles on it. I hope this gets better but I am convinced that adding this catch can is going to help my preignition situation and keep the engine cleaner.

Is this a problem more associated with Mopars? I've never noticed a problem with my SBC's. Thanks again for the recommendation.
 
I installed the Catch Can today. I have a baffle 3/4" below my PCV, so anything I'm picking up is vaporized mostly. After driving about 20 miles and "getting on it" 3 or 4 times, I pulled the canister off and there was a small puddle of oil in the bottom. This engine has about 800 miles on it. I hope this gets better but I am convinced that adding this catch can is going to help my preignition situation and keep the engine cleaner.

Is this a problem more associated with Mopars? I've never noticed a problem with my SBC's. Thanks again for the recommendation.
as far as I know, it is not a mopar specific problem. It probably has more to do with epa regulations and trying to really curtail hydrocarbon emissions, not just from the tailpipe, but from the fuel tank, and engine crankcase as well. With FI, engines run pretty clean, but sludge can form in engines which don't reach operating temp for long enough period of time to burn off moisture in the engine/engine oil. This can form a sludge, some of which you might see on the oil filler cap.
As far as SBC being immune to this problem, you can go on the Internet and see videos of GM owners trying to clean that stuff out of the intakes with Seafoam, and other chemicals.
 
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