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RIP (12/27/60-7/18/15)
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767 Posts
Discussion Starter #1
I need to plug the hole in my passenger side valve cover.
This is where the metal hose went to the air cleaner.
can I use a breather cap with the rubber gasket that's in the cover?
there's just a piece of tape over the hole now and it hasnt blown off yet so I assume there is little pressure there.
ideas?
thanks as always
Tk
 

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Super Moderator
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You could use a breather cap as you described... Be aware though that you need to have some path for crank-case pressure to vent, otherwise it can do things like cause leaks by "pushing out" seals and gaskets. Is there some reason you don't want to use the original vent tube?

Bear
 

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RIP (12/27/60-7/18/15)
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767 Posts
Discussion Starter #4
Well Bear, it went to the original AIR aircleaner. I removed the AIR system.
And want to use an open air cleaner. :)
Dosn't the pcv valve in the valley pan vent most of the gasses?
 

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Former Super Moderator
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The PCV (Positive Crankcase Ventilation) only vents when there is vacuum applied. When your at WOT there is no vacuum, so the blow-by needs somewhere to go or it blows out seals and gaskets. I have my valve cover breather routed under the intake with a hose. Doesn't leak or anything.
 

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:agree with what Rukee said. Also Top, my original air cleaner for my 69 (which did -not- have an AIR system on it) still had the tube from the passenger side valve cover to the rear of the air cleaner ---- and so does the reproduction Ram Air system I'm running now.

Bear
 

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I was on a road trip from Wichita to Omaha about ten years ago when my beather fell off of the valve cover. I could smell the oil burning on the headers. I stuffed a red rag into the hole and continued on. A few miles down the road, I had oil coming out of the right side of the hood next to the fender, and up on the windshield. The pressure pushed the dipstick out of the tube, and pumped at least a quart of oil all over the underside of the hood. That was a great trip.
 

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64-67 Expert
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8,561 Posts
OK Top: my Federal '67 GTO has an oil filler on the drivers side valve cover, and that is also the breather cap. Federal GTO's of this year had a solid rubber plug in the passenger side valve cover. The vendors have them. Use that, and a stock or repro Federal spec (vented) filler cap on the other cover and it will look correct, won't leak, and will breath fine.
 

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64-67 Expert
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AS a PS: 49 state '67 GTO's had no vent hose of any kind coming to the air filter. It was an open system. The only thing connected to the air filter housing is the carburetor! All that fancy emissions stuff didn't really start on federal cars until '68 or '69.
 

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Former Super Moderator
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AS a PS: 49 state '67 GTO's had no vent hose of any kind coming to the air filter. It was an open system. The only thing connected to the air filter housing is the carburetor! All that fancy emissions stuff didn't really start on federal cars until '68 or '69.
Mine has just the vented cap, but it messed up the valve cover with the oil vapor, so I switched to the filler cap with the hose.
 

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RIP (12/27/60-7/18/15)
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767 Posts
Discussion Starter #11
Ive just had a piece of masking tape over the passenger valve cover hole , and although there is a bit over an hour on the motor, the tape has not been blown off.
the drivers side cover has no holes in it.
Is this a problem?
thanks as always
 

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64-67 Expert
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8,561 Posts
Yes, TK, you need at least one vented valve cover. As stated, the original set-up would be a rubber plug in the pass side, and a vented, chrome cap in the driver's side. If you don't want to pay the $$$ at the vendors, Napa has them.
 
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