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Bellows
Posted by: mashad11 ()
Date: February 14, 2022 08:47PM

Is there a good explanation for how the driver and passenger side bellows are supposed to operate? I have seen a few posts but I have not seen anything that convinced me. Wondering if there is a technical guide about them and why driver side opens first.

Ali S
'65 Coupe - 140 - 4 Speed
Los Angeles

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Re: Bellows
Posted by: MattNall ()
Date: February 14, 2022 09:29PM

When the air reaches 225F they expand! Drivers side open first since its not allowed to ever be fully closed...look closely!

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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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...............110-PG.................................................Webered-Turbo

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Re: Bellows
Posted by: caroseiii ()
Date: February 14, 2022 09:40PM

Also, oil cooler is very hot first.

Crawford

C.A. Rose
Metairie, LA
1962 Spyders

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Re: Bellows
Posted by: 66vairman ()
Date: February 14, 2022 09:50PM

MattNall Wrote:
-------------------------------------------------------
> When the air reaches 225F they expand! Drivers side open first since its not allowed to ever be fully closed...look closely!

The winter summer plate either allows air into the engine compartment (winter), or holds the drivers side door partly open (summer). So your going to get more air flow over that bellows when the engine is warming up. There may be other things at play, but normally the drivers side bellows opens that door before the passenger side.

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Re: Bellows
Posted by: joelsplace ()
Date: February 14, 2022 09:58PM

I've heard lots of people say the oil cooler gets hot fast/first. That makes no sense to me. The exhaust manifolds heat up really fast and I would think the oil was the last thing to heat up.
I think the cooling works well enough that the doors close quickly when at lower speeds and after an engine is fully warmed up then the oil cooler side does have to dump a lot more heat but if you think about it the oil cooler is behind the thermostat. ???

Joel
Northlake, TX
5 Ultravans, 136 Corvairs and counting...

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Re: Bellows
Posted by: MattNall ()
Date: February 14, 2022 10:12PM

Correcto!

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: Bellows
Posted by: Lane66m ()
Date: February 15, 2022 01:54AM

Which side has the longer manifold? My memory says left. If so, then more heat is in the left shroud area quicker. Another guess of course.

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Re: Bellows
Posted by: irfgt ()
Date: February 15, 2022 02:09AM

There are many factors involved in which thermostat opens first. First is the condition, adjustment, and accuracy of the thermostat itself. Others include engine condition, carburetor adjustment, lower shroud condition including the doors, heater hose condition, possible exhaust leaks, and winter summer plate position. Very rarely will you see both sides open at the same time due to these factors.

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Re: Bellows
Posted by: 66vairman ()
Date: February 15, 2022 11:39AM

joelsplace Wrote:
-------------------------------------------------------
> I've heard lots of people say the oil cooler gets hot fast/first. That makes no sense to me. The exhaust manifolds heat up really fast and I would think the oil was the last thing to heat up.
> I think the cooling works well enough that the doors close quickly when at lower speeds and after an engine is fully warmed up then the oil cooler side does have to dump a lot more heat but if you think about it the oil cooler is behind the thermostat. ???

My experience is the oil heats up LAST. In fact some engines with an oil cooler, they use an oil thermostat to get the oil to operating temperature quicker. My 90 Vette had an interesting oil to antifreeze heat exchanger! The antifreeze got hot before the oil and transferred heat TO the oil, during hard engine use the oil transferred heat into the antifreeze. Clever and effective. /color]



Edited 2 time(s). Last edit at 02/15/2022 11:40AM by 66vairman.

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Re: Bellows
Posted by: 66vairman ()
Date: February 15, 2022 11:46AM

Lane66m Wrote:
-------------------------------------------------------
> Which side has the longer manifold? My memory says left. If so, then more heat is in the left shroud area quicker. Another guess of course.

You have heat transfer transfer by "radiant" and "convection" to the bellows. With the left side door closed there is very little heat transfer by convection, just radiant vs. the right side bellows that gets heat transfer by both convection and radiant.

You'll notice that when the left door starts to open, to allow convection heating of the bellows, that after the initial opening it moves fast, relatively speaking, to the right.

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Re: Bellows
Posted by: Lane66m ()
Date: February 15, 2022 12:26PM

Lost me on that explanation. Both side have same cool under lower shroud air. Both get same radiant heat until doors start to open. Left open first. Why.

My guess is more radiant heat from longer exhaust log.

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Re: Bellows
Posted by: MattNall ()
Date: February 15, 2022 12:45PM

Al, most likely the actual cause, but it's been refuted many times over the years
hen I've mentioned that.

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: Bellows
Posted by: mashad11 ()
Date: February 15, 2022 12:57PM

A while back I used a thermal camera to compare left and right. I should have measured the bellows too. The driver side is always a bit warmer.

Ali S
'65 Coupe - 140 - 4 Speed
Los Angeles

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Re: Bellows
Posted by: 66vairman ()
Date: February 15, 2022 02:46PM

Lane66m Wrote:
-------------------------------------------------------
> Lost me on that explanation. Both side have same cool under lower shroud air. Both get same radiant heat until doors start to open. Left open first. Why.
>
> My guess is more radiant heat from longer exhaust log.


NO the drivers side always has some air flowing over the bellows due to drivers side door that doesn't close completely (or up through the tin hole in Winter if the cover is in Winter position). CONVECTION is heat transfer due to air flow. Very little convection heat flow on passenger side when the door is closed. Yes radiant is about equal on both sides, but moving air transfers a lot more heat vs. radiant (air cooled engine). If you don't believe this then try driving a Corvair with the fan belt off and see how FAST the engine heads overheat sitting in still air!!

Better yet - look up flowing gases or fluids and heat transfer vs. still moving gases or fluids. The first thing you learn in how to survive in cold water is DON'T MOVE. Moving through cold water will pull heat off the body much faster than staying still!!

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Re: Bellows
Posted by: Lane66m ()
Date: February 15, 2022 04:22PM

Ok. Time for an Apple's to Apple's comparison.

A question to the owners who use a flat blanking plate on the left cooling box, instead of the factory summer/winter panel which kicks the left cooling door open a bit.

After starting your engine, does the left cooling door open faster on your engine with this configuration?

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Re: Bellows
Posted by: Lane66m ()
Date: February 15, 2022 04:31PM

Of course, if foam seals and the exhaust log flat gasket aren't used, uncontrolled air to the outside from the leaks will affect airflow under shroud. The affect on the bellows then will be an unknown. The big leakage going out the front will definitely enhance the convection cooling.

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Re: Bellows
Posted by: link9711 ()
Date: February 15, 2022 05:36PM

Well I watch mine the the left side opens frist and the right is kinda lagging bhind but opens.I think as long as they do there job and open and keep the eng cool is the main thing does not realy matter what one opens frist they are independent of each other and have a mind of there own.Also need to check the condition of the heater hoses in the back could have a hole or tear and letting air out that would go out the back but you would think the bellows with hot air on it would not matter and open same you would just feel less moving out the rear.

link9711
63 monza spyder
san antonio tx



Edited 1 time(s). Last edit at 02/15/2022 05:37PM by link9711.

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Re: Bellows
Posted by: Mike48750 ()
Date: February 18, 2022 12:33PM

That's a cool picture

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Re: Bellows
Posted by: toms73novass ()
Date: February 18, 2022 01:14PM

66vairman Wrote:
-------------------------------------------------------
> MattNall Wrote:
> -------------------------------------------------------
> > When the air reaches 225F they expand! Drivers side open first since its not allowed to ever be fully closed...look closely!
>
> The winter summer plate either allows air into the engine compartment (winter), or holds the drivers side door partly open (summer). So your going to get more air flow over that bellows when the engine is warming up. There may be other things at play, but normally the drivers side bellows opens that door before the passenger side.

That is for you LM guys! EM did not have the little cover with the extension attached. We have to bend flaps! grinning smiley

-Tom


63' Monza Spyder Convertable (in process) MY Build Thread
62' Wagon rebuild MY Build Thread
65' Monza MY Build Thread
73' NovaSS 454 Big block (Sold)
86' BMW 325es
67' UltraVan 211 "Violet"
NFCC, UMCC
Grand Island, NY

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Re: Bellows
Posted by: RexJohnson ()
Date: February 18, 2022 03:12PM

The early model factory A/C cars and the Spyders had removable covers but no extensions. Some of the FC might have had the removable cover also.

RJ tools
Salem,Oregon

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