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Another PCV question!? Sorry!
Posted by: rick4130 ()
Date: October 25, 2017 09:07AM

So in the attached picture I found, with no real PCV valve, this guy has the hoses going from vent tube right into the base of each carb, when the carb balance tube does the same thing, and it's attached to that too! Is this even doing anything, and if it is, isn't it super redundant?

Rick MacDonald
'63 700 Sedan

rick4130@yahoo.com

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Re: Another PCV question!? Sorry!
Posted by: rick4130 ()
Date: October 25, 2017 09:10AM

And does it matter that the upper hoses are above the carb, and balance tube is at the base? What is really going on here?? Haha

Rick MacDonald
'63 700 Sedan

rick4130@yahoo.com

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Re: Another PCV question!? Sorry!
Posted by: cnicol ()
Date: October 25, 2017 09:22AM

Your two posts said different things so I'm not sure what's going on either but looking at the second picture:

If the vent tubes are connected above the carburetors and the "tee" on the metal vent pipe is connected to the nipple on the vacuum balance tube, then you have a properly modified but "normal" PCV system. The late-model vent tube (with the "Tee" fitting/nipple) is actually a controlled orifice that uses manifold vacuum to sweep vapors into the intake manifold. When the vacuum isn't enough to manage the blowby, excess vapor is routed to the top of the carbs for "consumption".

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe (sold, sniff sniff)
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts




Edited 1 time(s). Last edit at 10/25/2017 09:26AM by cnicol.

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Re: Another PCV question!? Sorry!
Posted by: RobertC ()
Date: October 25, 2017 09:38AM

As Craig stated...

There is no PCV valve in the LM system. There is a metered orifice small hole (in one side of the tube) that is connected to the balance tube.

The large hole of the tube inserted into the base (rubber grommet) of the stock air cleaner.

In the pic, this is accomplished by the tee that routes hose into the base of the individual air cleaners.

"Technically", you only need to route one hose into the base of one air cleaner. What my mechanic did with a modified 65 PCV tube into the base of one Otto Parts air cleaner.



Edited 1 time(s). Last edit at 10/25/2017 09:39AM by RobertC.

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Re: Another PCV question!? Sorry!
Posted by: rick4130 ()
Date: October 25, 2017 09:47AM

Oh yeah, I am overthinking it for sure... thanks guys! I didn't even realize it may be a LM arrangement.

Rick MacDonald
'63 700 Sedan

rick4130@yahoo.com

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Re: Another PCV question!? Sorry!
Posted by: CoCoCo ()
Date: October 25, 2017 05:11PM

In addition to letting excess vapors stay in the engine and get gently sucked into the carburetors, I think the actual primary function of the "closed" system like this and like factory setup is so that only clean, filtered air gets sucked into the engine through the balance tube when vacuum is high.

Yes the remaining vapors do get sucked into the top of the carburetor, but if the tube was left open instead of routed directly to the carburetor air filter(s) then contaminated air would be ingested.

Filtering is good...thumbs up

Paul

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Re: Another PCV question!? Sorry!
Posted by: MattNall ()
Date: October 25, 2017 05:19PM

Not Clean... but a predetermined METERED amount...

Crank Cover / Fan mount's Baffle separates the large oil droplets..





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Another PCV question!? Sorry!
Posted by: TerribleTed ()
Date: October 25, 2017 05:34PM

rick4130 Wrote:
-------------------------------------------------------
> So in the attached picture I found, with no real
> PCV valve, this guy has the hoses going from vent
> tube right into the base of each carb, when the
> carb balance tube does the same thing, and it's
> attached to that too! Is this even doing
> anything, and if it is, isn't it super redundant?

A lot of people simply install a smaller filter similar to the ones on the carbs onto the tube coming out the top of the shroud. Seems to work. You could do this and eliminate the T fitting and rubber hoses that run into the carb air filter bases.

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
[www.facebook.com]

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Re: Another PCV question!? Sorry!
Posted by: jmaechtlen ()
Date: October 25, 2017 05:37PM

Since crankcase blowby is some combination of exhaust gas and unburned air-fuel mix, better to share it between the two carbs. It reduces the change in mixture and spreads it across both banks.

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Re: Another PCV question!? Sorry!
Posted by: American Mel ()
Date: October 25, 2017 06:38PM

TerribleTed Wrote:
-------------------------------------------------------
> rick4130 Wrote:
> --------------------------------------------------
> -----
> > So in the attached picture I found, with no
> real
> > PCV valve, this guy has the hoses going from
> vent
> > tube right into the base of each carb, when the
> > carb balance tube does the same thing, and it's
> > attached to that too! Is this even doing
> > anything, and if it is, isn't it super
> redundant?
>
> A lot of people simply install a smaller filter
> similar to the ones on the carbs onto the tube
> coming out the top of the shroud.
Seems to work.
> You could do this and eliminate the T fitting and
> rubber hoses that run into the carb air filter
> bases.

This is true, but those people that are blessed with superior olfactory senses, can find this method to be offensive to their idea of a good time, when using the "Fresh Air Heater" that your car was designed with !
.
Hot Oil smells can be blown into the car.

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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Re: Another PCV question!? Sorry!
Posted by: Seth Emerson ()
Date: October 25, 2017 07:22PM

Mel writes:

"This is true, but those people that are blessed with superior olfactory senses, can find this method to be offensive to their idea of a good time, when using the "Fresh Air Heater" that your car was designed with !
.
Hot Oil smells can be blown into the car."



Well that sucks! And of course, there might be some Carbon Monoxide as well. DOH!

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Re: Another PCV question!? Sorry!
Posted by: American Mel ()
Date: October 25, 2017 07:52PM

Yeah, there is that also.sad smiley

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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Re: Another PCV question!? Sorry!
Posted by: davemotohead ()
Date: October 25, 2017 07:57PM

I love the smell of Carbon Monoxide in the morning! that sweet sweet burnt oil smell! smoking smiley





Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)

-----------------------------------
Rust Free Lancaster Ca

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Re: Another PCV question!? Sorry!
Posted by: cnicol ()
Date: October 25, 2017 08:05PM

Folks who install an air filter on the PCV pipe instead of routing it to the air cleaner sometimes don't understand what they're really doing.

50% of the unburned (aromatic) hydrocarbon (aka "HC") produced by an engine comes from the crankcase.

Blowby gas production increases as engine load and rpm increases. At the same time, manifold vacuum is lower and lower so very little blowby volume is taken by manifold vacuum. Virtually the full blowby gas flow comes OUT of that little filter and it goes right into the heater! Yum!

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe (sold, sniff sniff)
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

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Re: Another PCV question!? Sorry!
Posted by: flamingchariots ()
Date: October 26, 2017 01:42PM

A few years ago, there were times when we took the '65 to church in late fall.
Before we got things straightened out, people around us could always tell which car we drove...




Kevin
Medina, OH

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Re: Another PCV question!? Sorry!
Posted by: TerribleTed ()
Date: October 26, 2017 02:44PM

I have driven cars set up that way and did not notice any smell issues, BUT, I am sure you all are correct. In thinking about it, most cars I have seen that way were also not running lower shrouds either so that may not be an issue really. So to correct my above postsmiling smiley You should connect the end of the PCV orifice tube to air cleaner setup. What is in the photo should be functional just not real pretty.

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
[www.facebook.com]

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Re: Another PCV question!? Sorry!
Posted by: American Mel ()
Date: October 26, 2017 03:24PM

"You should connect the end of the PCV orifice tube to air cleaner setup. What is in the photo should be functional just not real pretty."

Correct.

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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Re: Another PCV question!? Sorry!
Posted by: MattNall ()
Date: October 26, 2017 05:23PM

NO!!


Orifice tube is 3/8" goes to BALANCE tube

Main tube is 1/2" and goes to Air cleaner/ s


The EMs / FC's that used the PC valve, used an UN-orificed 3/8" tube to the right side air filter..





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Another PCV question!? Sorry!
Posted by: American Mel ()
Date: October 26, 2017 05:59PM

Uh, NO, it IS YES!

Matt, the picture, and statement is correct !
The "T-ed off orifice tube goes to the balance tube.
And "the open end" goes to the Air cleaner.
Otherwise as stated above, . . .
if left to atmosphere, it will be sucked into the engine cooling fan and be blown into the passenger compartment!

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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