What is this, an early PCV system??? - Team Camaro Tech
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post #1 of 9 (permalink) Old Mar 12th, 17, 01:18 PM Thread Starter
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Bruce
 
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What is this, an early PCV system???

Took the top end off of my 67 327, built in late '66. Found this funny can looking thing, I believe it's attached to the vacuum port attachment at the rear arrow.

This was connected to full time vacuum on the intake, through what looked like a PCV valve. The PCV valve was at the back of the carb, not where you'd normally see it.

Anyone seen this before?
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post #2 of 9 (permalink) Old Mar 12th, 17, 02:01 PM
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Re: What is this, an early PCV system???

it was the early crankcase breather. it originally had a metal tube that came out from the back of the block and down
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post #3 of 9 (permalink) Old Mar 12th, 17, 02:11 PM
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Re: What is this, an early PCV system???

Quote:
Originally Posted by Coach62 View Post
Anyone seen this before?
That can works as an oil separator. Don't try running without it unless you plug the outlet hole and run another type of pcv system. If you try running the old pcv system without that can, you will suck a lot of oil into the intake manifold.

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post #4 of 9 (permalink) Old Mar 12th, 17, 02:23 PM
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Re: What is this, an early PCV system???

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Originally Posted by flat tire View Post
it was the early crankcase breather. it originally had a metal tube that came out from the back of the block and down
Camaros never used the road draft tube that vented down onto the road. I think they were phased out by the early sixties.
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post #5 of 9 (permalink) Old Mar 12th, 17, 03:37 PM Thread Starter
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Bruce
 
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Re: What is this, an early PCV system???

Thanks everyone. So I could plug that off, and run a "modern" PCV system off of a valve cover breather??

The hose that went from that nipple to the intake had what appeared to be a modern PCV valve on it where it connected to the intake. Do I actually need the modern PCV valve at the intake if the oil separator is already there, if I chose to keep this current setup?
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post #6 of 9 (permalink) Old Mar 12th, 17, 04:19 PM
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Re: What is this, an early PCV system???

The '67 327 had a PCV valve and an "open" PCV system shown here. Air is pulled in through the breather oil filler cap at the front of the intake manifold and the crankcase vapors are pulled from the canister at the back of the engine through the PCV valve by manifold vacuum at the front of the carb. Mine hasn't been altered and functions fine.
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1967 RS 327/275hp
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post #7 of 9 (permalink) Old Mar 12th, 17, 04:32 PM
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Re: What is this, an early PCV system???

Do not throw that can out. Run of the mill vendors do not sell it. Paragon does sell the vent tube at the back of the block, limited quantity.

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Last edited by Sauron67MM; Mar 12th, 17 at 04:44 PM.
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post #8 of 9 (permalink) Old Mar 12th, 17, 07:31 PM Thread Starter
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Re: What is this, an early PCV system???

Quote:
Originally Posted by dyno jonn View Post
That can works as an oil separator. Don't try running without it unless you plug the outlet hole and run another type of pcv system. If you try running the old pcv system without that can, you will suck a lot of oil into the intake manifold.
Quote:
Originally Posted by trland View Post
The '67 327 had a PCV valve and an "open" PCV system shown here. Air is pulled in through the breather oil filler cap at the front of the intake manifold and the crankcase vapors are pulled from the canister at the back of the engine through the PCV valve by manifold vacuum at the front of the carb. Mine hasn't been altered and functions fine.
Thank you everyone, thanks a ton Mike for that attachment. I saved it for later use.

Will any PCV valve work, or should I get the correct one? Mine is plumbed differently, it goes into the back of the carb.

One last question, I assume it gets connected to a full-time vacuum source, correct?

It seems this method would be prone to leaning out, particularly if the PCV valve fails. Seems like the connection to the air filter would make more sense from a potential leaning out position, agree?? A somewhat free flow of air AFTER the carb concerns me.
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post #9 of 9 (permalink) Old Mar 13th, 17, 07:54 AM
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Scott
 
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Re: What is this, an early PCV system???

Quote:
Originally Posted by Coach62 View Post
One last question, I assume it gets connected to a full-time vacuum source, correct?

It seems this method would be prone to leaning out, particularly if the PCV valve fails. Seems like the connection to the air filter would make more sense from a potential leaning out position, agree?? A somewhat free flow of air AFTER the carb concerns me.
Yes, full time manifold vacuum source, either from the intake manifold or base of the carburetor.

This method is the only method for a PCV system and no it is not prone to leaning out. The carburetor is adjusted with the PCV valve functioning so it is already compensated for. How do you think a PCV valve could "fail" to cause a lean condition, it would have to fail in the fully open position and even then it would not draw much more through it than it does with the plunger bouncing against the spring in normal operation?

A connection to the air filter is for a valve cover breather, the other half of a more modern PCV system. The breather lets fresh air into the valve cover if/when needed, it draws very little air out of the valve cover most of the time due to the minimal vacuum/suction in the air cleaner housing, the PCV valve has much greater vacuum/suction due to it being connected to a manifold vacuum source. The system you had worked fine, nothing to worry about or change unless you are going with a later engine block that doesn't have provisions machined in it for the same system, then a change would be necessary.
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