Tapping PCV hole on MP Perf. Valve Covers..

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Beatnik

Beatnik

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Got my new MP Performance black valve covers, and the PCV hole has to be tapped out on the drivers side cover for my Holley. How have you guys done this? Instructions say just to take a punch and a hammer and punch it out, then round file it down. Anyone have a better/cleaner suggestion? A hole saw or something?

Thanks! Just thought I'd ask, you never know when someone has a good trick...
 
I used a hole saw since it was handy at my bench. Qucik and easy from start to finish.
 
Hole saw is likely a good idea. I did mine with a punch, and they turned out great also. Very little filing.

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Thanks guys...couple other questions. What size punch did you use? And what kind of hole saw bit did you use?

Did you guys do both covers and put a breather on the other side?

Nemo- You have your factory air cleaner vent going to the front tube right? Did you punch the back hole too on the drivers side?
 
I used to take the ball end of a ball pein hammer. Lay it on the top of the cover where the knock out is and tap the face end with another hammer.
Mike
 
Yeah you'll need a breather on the other side for the pcv to work correctly.

I had problems with my covers blowing a little oil from the breather and sucking a little up in the pcv valve. I made a set of baffles and installed them (the screw mounts are allready under there) and that resolved the issues.
 
Thanks guys...good ideas. Fishy- I actually ordered an extra set of baffles to under the two extra holes from MP. In the instructions it gives you the part # for baffles and gromets and hardware so I ordered them.

I have dumb question. If you are running the OEM closed air cleaner like Nemo's pic above, and it's vented to the cover. Do you need to knock out the other section for a Holley PCV hose? It's one or the other right? Also, does the passenger side forsure need to be knocked out for a breather?

Thanks again..!

If anyone has more pics of their smallblock with these covers please post them! I'd like to see different set-ups since I'm going to get a new carb too...either Edelbrock or Holley.
 
Unless I'm misunderstanding something, one valve cover needs to have a breather or be attached to the air cleaner & the other cover, with the pcv valve, needs to be hooked to the base of the carb.
 
I knocked out the front on the passenger side, and ran that to the carb. I only knocked out one hole per cover. I just used a 1/2 inch drift punch. I also used loctite on the baffle screws(I wasn't too confident in the way they screw in)
 
Hey guys thanks for the replies. Let me simplify my question...

I'm currently running an open element air cleaner, and my PCV connects from the back of my Holley 650 to the drivers side cover rear portion on my chrom Edelbrock covers. There is only one hole. The passenger side cover just has a breather on it.

If I switch the the OEM black vented air cleaner (like Nemo's). I just need to cap the carb port and run the vent tube from the air cleaner to the drivers side portion that's already tapped right? It's on or the other right?

Then the passenger side stay's the same, breather on the one tapped hole.
 
motorpirate said:
No,PCV stays on the carb,Breather goes to the air cleaner.
Click to expand...

Thanks, after more researching I see that to be the case. I've just never run one of the vented OEM air cleaner assemblies. Why do they make the vented and non-vented versions? What's the point? Most people seem to be using the vented version. I'd like to get one, I like the pie-tin look and black case but why get a vented one or non-vented one?
 
The air cleaner, as pictured above, is a MoPar part, repro part of the HP un-silenced air cleaner I believe. As they are an OE part, the breather on the cleaner is stock.

MoPar also sells it in chrome with and without the breather tube. Most people like myself like the black wrinkle. But it doesn't come without the tube, only with the tube.

The bennifit to a breather to is to create a vacuum so the burning oil thats making smoke gets sucked up into the breather keeping the engine cleaner inside.
This vacuuming of the inside also relieves pressure that can result in gasket blow out if left unvented. (Sealed) A simple vent on top is a min. to have IMO, though not a mandotory item to run.
 
I don't know this for fact but I always guessed it was cheaper for the factory to just run a pipe to the air cleaner and use it for a combination air cleaner/valve cover breather than it is to install a separate breather. Pipe probably cost about .50 and a breather probably cost about .75-1.00 factory prices. Considering all the cars they sold .25-.50 saving per car ads up to allot over the yrs.
 
Excessive blow by from a worn engine to an unvented cap goes on the valve cover, right? The vented cap was part of California emission standards before madatory across the board. The crankcase air filter (if you can call it that) is inside the cap in either case.
 
I think it was part of the CCVS (Closed Crankcase Ventilation System). Earlier systems just used a valve cover breather & a PCV valve but this system had less chance for fumes, etc. getting into the atmosphere. Anything expelled would immediately be drawn into the engine through the air cleaner/carb. Plus, as rumble said, it keeps the inside of the engine cleaner. Most likely a Govt. mandated primitive pollution control system. The older systems would just vent into the engine compartment. It probably also kept the top of the valve cover a bit cleaner. (Not to mention the even older "road draft" tubes. Remember them?)
 
Hey guys, thanks for all the good info, so if the factory air cleaner/breather system hooks to the drivers side cover (as I've seen it mostly) then were was the factory PCV from the carb going to? Passenger side?

If I get OEM black wrinkle air cleaner, and hook the breather to the drivers side valve cover, then where am I supposed to go with my PCV from my carb? Passenger side? Or tap the rear hole on the drivers side cover use it? Then I'd have both holes on the drivers side being used and just a breather cap on the passenger side.

Does any of that make sense? It's hard to explain.
 
MtNemoMopar said:
I knocked out the front on the passenger side, and ran that to the carb. I only knocked out one hole per cover. I just used a 1/2 inch drift punch. I also used loctite on the baffle screws(I wasn't too confident in the way they screw in)
Click to expand...

After re-reading this I think Nemo's got me covered. Nemo- Are you running a Holley carb that has the PCV outlet on the firewall side? So you ran your PCV to the passenger side? (your pic is good but doesnt show the pass. side very well)

Thanks!
 
The pcv valve should be on one and breather cap on the other. Dunno if sides matters.
 
I think the breather onthe passenger side offers the best amount of room. It also places it back alittle father so it doesn't look like it is in your face.
 
rumblefish360 said:
I think the breather onthe passenger side offers the best amount of room. It also places it back alittle father so it doesn't look like it is in your face.
Click to expand...


Got any pics of this set-up? Anyone got more pics of their set-up? Nemo's the only pic poster so far...
 
No pictures, but the hole saw you want to siae to the gromets smallest outside diameter. Center and drill away. Clean, install gromet then whatever part (PVC, Breather etc...) you want/have.
 
My PVC runs from the front of the passenger side cover, to the base of the carb on the passenger side,towards the rear. I'm running a Holley 670 Street Avenger carb.
 
OK, I climbed up the shelf and let them defrost before I took'em apart for a picture by picture install.
No back into the cold to put'em away.

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