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which temp thermostat, 180 or 195? [message #147356] Sat, 22 October 2011 08:40 Go to next message
RF_Burns is currently offline  RF_Burns   Canada
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In the spring of 2009 I had the rad repaired and got a new thermostat from JimK. At the time he had only one listed on his site which turned out to be a 180* (80*C).

On the last couple of trips the water temp has been as low as 72C and as high as 92C according to the EBL Whats up display. The dash gauge which has its own sensor shows lower and higher as well so I don't think I have a sensor problem. Both used to read rock solid at 80C.

So it looks like a new thermostat is in the future. Which thermostat should I be using for a 77 with a 455? Is there any benefit to using the higher or preferably lower temp stat?

Thanks


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

[Updated on: Sat, 22 October 2011 08:53]

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Re: which temp thermostat, 180 or 195? [message #147359 is a reply to message #147356] Sat, 22 October 2011 09:05 Go to previous messageGo to next message
armandminnie is currently offline  armandminnie   United States
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Location: Marana, AZ
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Your heater will work better with the 195 and I have been told that the 455 was designed to work at the higher temps.

Armand Minnie
Marana, AZ
'76 Eleganza II TZE166V103202
visit my gmc blog
click here to visit gmcws.org
Re: [GMCnet] what temp thermostat, 180 or 195? [message #147362 is a reply to message #147356] Sat, 22 October 2011 09:36 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Bruce, I will try to explain the difference. The real purpose of the
thermostat is to speed warm up of the coolant in the engine. It blocks
circulation until the specified temperature has been reached, and then opens
fully. At that point, it's job is more or less finished. Open is open. If
your temp is climbing and then falling, it sounds like perhaps it might be
time for a new Robert Shaw. They can be identified by the fact that they
have three support legs holding the temperature sensing element and are much
more durable than the two leg style. They come in various temp ranges, and
are sold by a number of different brands. Shop around, prices vary, but both
the Jim's have them in stock. I personally would not install any other style
in any engine I cared about. I always look for one additional feature and
that is that when they fail, they do so in the open position, not the closed
one. An engine will overheat very quickly when the thermostat is stuck in
the closed position. Hope this helps. Oh, by the way, my preference is 180
degree but there is nothing wrong with the 195 degree. The amount of heat
the engine is producing is the same either way.
Jim Hupy
Salem, OR
78 GMC Royale 403

On Sat, Oct 22, 2011 at 6:40 AM, Bruce Hislop <bruce@perthcomm.com> wrote:

>
>
> In the spring of 2009 I had the rad repaired and got a new thermostat from
> JimK. At the time he had only one listed on his site which turned out to be
> a 180* (80*C).
>
> On the last couple of trips the water temp has been as low as 72C and as
> high as 92C according to the EBL Whats up display. The dash gauge which has
> its own sensor shows lower and higher as well so I don't think I have a
> sensor problem. Both used to read rock solid at 80C.
>
> So it looks like a new thermostat is in the future. Which thermostat should
> I be using for a 77 with a 455? Is there any benefit to using the higher or
> preferably lower temp stat?
>
> Thanks
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
> Hubler 1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Re: [GMCnet] what temp thermostat, 180 or 195? [message #147372 is a reply to message #147362] Sat, 22 October 2011 10:38 Go to previous messageGo to next message
WD0AFQ is currently offline  WD0AFQ   United States
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Bruce, I run the 180 in summer and 195 in winter. I have no heat with the 180 so I always put the 195 in for winter. Opinions will vary. I also buy the fail open ones. I have had one fail closed, on my Mustang, and it will heat up very fast.
Dan


3 In Stainless Exhaust Headers One Ton All Discs/Reaction Arm 355 FD/Quad Bag/Alum Radiator Manny Tran/New eng. Holley EFI/10 Tire Air Monitoring System Solarized Coach/Upgraded Windows Satelite TV/On Demand Hot Water/3Way Refer
Re: [GMCnet] what temp thermostat, 180 or 195? [message #147384 is a reply to message #147372] Sat, 22 October 2011 11:59 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Location: Belmont, CA
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What I have heard from people that work on RV engines are as follows:
180 will give you an edge when starting up hill as there is a greater
chance that it will be 180 at the base of the hill and will increase
by the time your up toward the top,
The difference can be 20 degrees. Add 20 to 180=200, add 20 to 195=215.
When the system runs cooler, we feel there is a chance that there
would be less stress applied to component parts by trying to keep the
temp lower.
I have been told by customers that our High flow Thermostats are the
correct Robert Shaw as it holds the seal when cold, not like the
others that are supplied and look identical.
This sounds like bull, but Steve Ferguson and others have blown on
them and made the statement.
I recall that Wes at Cinnabar printed a statement that he final drive
units can only accept a 3.42 ratio. We can put in 3.55 and 3.70 with
no modification. I make some statements and claims, but not that far
fetched.



--
Jim Kanomata
Applied/GMC, Fremont,CA
jk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Re: [GMCnet] what temp thermostat, 180 or 195? [message #147399 is a reply to message #147384] Sat, 22 October 2011 17:02 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
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Location: Sydney, Australia
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Bruce,

What Jim is talking about below is that Robertshaw makes "racing" thermostats that do note close all the way; they bypass flow no
matter what the engine water temp is.

I've Cc'd Gene Dotson on this email as I believe he can supply more info.

Regards,
Rob M.

-----Original Message-----
From: Jim Kanomata

I have been told by customers that our High flow Thermostats are the correct Robert Shaw as it holds the seal when cold, not like
the others that are supplied and look identical.

This sounds like bull, but Steve Ferguson and others have blown on them and made the statement.

Jim

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Re: [GMCnet] what temp thermostat, 180 or 195? [message #147417 is a reply to message #147362] Sat, 22 October 2011 18:50 Go to previous messageGo to next message
fred v is currently offline  fred v   United States
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Location: pensacola, fl.
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James Hupy wrote on Sat, 22 October 2011 09:36

Bruce, I will try to explain the difference. The real purpose of the
thermostat is to speed warm up of the coolant in the engine. It blocks
circulation until the specified temperature has been reached, and then opens
fully. At that point, it's job is more or less finished. Open is open. If
your temp is climbing and then falling, it sounds like perhaps it might be
time for a new Robert Shaw. They can be identified by the fact that they
have three support legs holding the temperature sensing element and are much
more durable than the two leg style. They come in various temp ranges, and
are sold by a number of different brands. Shop around, prices vary, but both
the Jim's have them in stock. I personally would not install any other style
in any engine I cared about. I always look for one additional feature and
that is that when they fail, they do so in the open position, not the closed
one. An engine will overheat very quickly when the thermostat is stuck in
the closed position. Hope this helps. Oh, by the way, my preference is 180
degree but there is nothing wrong with the 195 degree. The amount of heat
the engine is producing is the same either way.
Jim Hupy
Salem, OR
78 GMC Royale 403




Jim, if i understand what you are saying the 180 will open at 180 and stay open but the 195 won't open till you reach 195 and then stay open. that tells me that, if the cooling system is OK, the engine will operate at 180 or 195 depending on which one you use. so, on a hot day pulling a toad up a long grade the engine will heat up no matter which one you use but it looks like the 180 will give you a head start on not overheating.
am i thinking right?


Fred V
'77 Royale RB 455
P'cola, Fl
Re: [GMCnet] what temp thermostat, 180 or 195? [message #147425 is a reply to message #147417] Sat, 22 October 2011 19:50 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
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Registered: March 2004
Location: Americus, GA
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Senior Member
First off, let me state that I'm an advocate of the OEM 195*F thermostat.
But I agree with the logic of having the "15*F safety margin at the bottom
of the hill". So I wondered just how significant that benefit really is.
Y'All check the logic and mathematics of the following:

One British Thermal Unit [Btu] is the amount of heat required to raise the
temperature of 1 pound [ lb.] of water 1 degree Fahrenheit.

H20 weighs 8.33 pounds per gallon

GMCMH holds 21 qt. (call it 24 w/H20 heater) = 6 gal

6 * 8.33 = 49.98 lb ~=50 lb

1 hp = 42 Btu/min (look it up on the internet or calculate from 1 hp = 746
Watts & 1 Watt=3.412 Btu per hour)

Therefore 1 hp should raise 50 lb H20 by 42/50 = 0.84 degrees F per minute

Or 1 hp should raise the temperature by 15 degrees F in 15/0.84 = 17.9
minutes

Conversely, 17.9 hp would raise the temperature by 15 degrees F in one (1)
minute.

Since I'd expect the ascent of a grade steep enough to cause overheating
concern to require AT LEAST an additional 18 hp, after 1 minute my "15*F
safety margin" will be lost.

For that meager improvement, I'll retain the greater efficiency benefits of
the 195*F thermostat. Especially since, with my AL radiator, even the
Cad500, has no problem maintaining normal temperature.

JMHO,

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com



On Sat, Oct 22, 2011 at 7:50 PM, fred veenschoten wrote:

>
> ...
> Jim, if i understand what you are saying the 180 will open at 180 and stay
> open but the 195 won't open till you reach 195 and then stay open. that
> tells me that, if the cooling system is OK, the engine will operate at 180
> or 195 depending on which one you use. so, on a hot day pulling a toad up a
> long grade the engine will heat up no matter which one you use but it looks
> like the 180 will give you a head start on not overheating.
> am i thinking right?
>
> --
>
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Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: which temp thermostat, 180 or 195? [message #147433 is a reply to message #147356] Sat, 22 October 2011 20:33 Go to previous messageGo to next message
RF_Burns is currently offline  RF_Burns   Canada
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Can I disagree with this statement without being flamed?

"It blocks circulation until the specified temperature has been reached, and then opens fully. At that point, it's job is more or less finished. Open is open"

I'm not an engineer so please correct me if I'm wrong here... but I believe the thermostat will "modulate" the flow of coolant through it based on the temperature of the coolant around it. From stone cold it will be closed until until the coolant around it reaches its "rated" temperature, then it will start to open. At this time cold coolant from the rad will begin to flow into the engine and the engine will begin to warm this coolant as the hot coolant is being cooled by the rad.
If the coolant flows through too fast to heat it to the rated temp, the thermostat will begin to close and slow the flow rate through the engine until it reaches the rated temp around the thermostat. At that point the thermostat will begin to open more.

Of course if the coolant is above the rated temperature, it will stay wide open... but the cooling system must be designed to dissipate more heat than the maximum developed by the engine on the hottest summer day otherwise the roads would be filled with overheated engines.

Just my Farmboy mechanic way I see it anyway. Otherwise I can tell you there is no way a lightly loaded engine at -40C would ever stay warmed up!

I'm sure mine is just sticking.. open and it gets cooler (72C) then partially closed and it gets hotter (92C).

Ok, my rotten tomato shields are up.. go for it!
Cool


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Re: [GMCnet] what temp thermostat, 180 or 195? [message #147441 is a reply to message #147417] Sat, 22 October 2011 21:10 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Fred, in theory it is how it should work.
For me that concept works on a ambient temp up to 80degrees F.
After that I find that it does not really make much difference.
Also the theory of higher temp will dissipate heat more rapidly as the
difference in temp is greater.
All I can say is that the 195 seems to keep me warm on a cool day.


Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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1-800-752-7502
Re: [GMCnet] which temp thermostat, 180 or 195? [message #147451 is a reply to message #147433] Sat, 22 October 2011 21:59 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
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Bruce,

Did a Google search and came up with a couple of references:

http://auto.howstuffworks.com/question248.htm

http://en.wikipedia.org/wiki/Thermostat - Scroll down to Wax Pellet - Automotive

This paragraph supports your statement.

Regards,
Rob M.


-----Original Message-----
From: Bruce Hislop

Can I disagree with this statement without being flamed?

"It blocks circulation until the specified temperature has been reached, and then opens fully. At that point, it's job is more or
less finished. Open is open"

I'm not an engineer so please correct me if I'm wrong here... but I believe the thermostat will "modulate" the flow of coolant
through it based on the temperature of the coolant around it. From stone cold it will be closed until until the coolant around it
reaches its "rated" temperature, then it will start to open. At this time cold coolant from the rad will begin to flow into the
engine and the engine will begin to warm this coolant as the hot coolant is being cooled by the rad.
If the coolant flows through too fast to heat it to the rated temp, the thermostat will begin to close and slow the flow rate
through the engine until it reaches the rated temp around the thermostat. At that point the thermostat will begin to open more.

Of course if the coolant is above the rated temperature, it will stay wide open... but the cooling system must be designed to
dissipate more heat than the maximum developed by the engine on the hottest summer day otherwise the roads would be filled with
overheated engines.

Just my Farmboy mechanic way I see it anyway. Otherwise I can tell you there is no way a lightly loaded engine at -40C would ever
stay warmed up!

I'm sure mine is just sticking.. open and it gets cooler (72C) then partially closed and it gets hotter (92C).

Ok, my rotten tomato shields are up.. go for it!
8)
--
Bruce

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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426
Re: [GMCnet] which temp thermostat, 180 or 195? [message #147452 is a reply to message #147451] Sat, 22 October 2011 22:13 Go to previous messageGo to next message
Bruce Hart is currently offline  Bruce Hart   United States
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Registered: October 2011
Location: La Grange, Wyoming
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Senior Member
As a shade tree mechanic, before I ever put in a thermostat I would heat it
up on the stove to be sure it would open, what I noticed was as it heated to
temperature the thermostat would slowly open up . If it is fully opened at
180 than would it start to open at 150, or 160. I didn't have a thermometer
at the time, I was just checking to see if it wold open and close.

Bruce Hart
Colorado
GMC wannabee


On Sat, Oct 22, 2011 at 8:59 PM, Rob Mueller <robmueller@iinet.net.au>wrote:

> Bruce,
>
> Did a Google search and came up with a couple of references:
>
> http://auto.howstuffworks.com/question248.htm
>
> http://en.wikipedia.org/wiki/Thermostat - Scroll down to Wax Pellet -
> Automotive
>
> This paragraph supports your statement.
>
> Regards,
> Rob M.
>
>
> -----Original Message-----
> From: Bruce Hislop
>
> Can I disagree with this statement without being flamed?
>
> "It blocks circulation until the specified temperature has been reached,
> and then opens fully. At that point, it's job is more or
> less finished. Open is open"
>
> I'm not an engineer so please correct me if I'm wrong here... but I believe
> the thermostat will "modulate" the flow of coolant
> through it based on the temperature of the coolant around it. From stone
> cold it will be closed until until the coolant around it
> reaches its "rated" temperature, then it will start to open. At this time
> cold coolant from the rad will begin to flow into the
> engine and the engine will begin to warm this coolant as the hot coolant is
> being cooled by the rad.
> If the coolant flows through too fast to heat it to the rated temp, the
> thermostat will begin to close and slow the flow rate
> through the engine until it reaches the rated temp around the thermostat.
> At that point the thermostat will begin to open more.
>
> Of course if the coolant is above the rated temperature, it will stay wide
> open... but the cooling system must be designed to
> dissipate more heat than the maximum developed by the engine on the hottest
> summer day otherwise the roads would be filled with
> overheated engines.
>
> Just my Farmboy mechanic way I see it anyway. Otherwise I can tell you
> there is no way a lightly loaded engine at -40C would ever
> stay warmed up!
>
> I'm sure mine is just sticking.. open and it gets cooler (72C) then
> partially closed and it gets hotter (92C).
>
> Ok, my rotten tomato shields are up.. go for it!
> 8)
> --
> Bruce
>
> _______________________________________________
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> Unsubscribe or Change List Options:
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming
Re: [GMCnet] which temp thermostat, 180 or 195? [message #147458 is a reply to message #147452] Sat, 22 October 2011 23:06 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
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Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
Anyone planning to test a thermostat should really check page 6K6 of X-7475
(probably in the others too): It specifies using a 33% glycol solution to
check for opening at 220*F and closing at 185*F (using a 195*F thermostat,
per spec, of course).

I read that 220*F full open spec as indicating that the cooling system
should have enough excess capacity for the thermostat to maintain the spec
195*F when PARTIALLY open.

By the way, photos there show how the thermostat should be oriented when
installed.

JWITIK,

Ken H.



On Sat, Oct 22, 2011 at 11:13 PM, Bruce Hart <hartsgmc@gmail.com> wrote:

> As a shade tree mechanic, before I ever put in a thermostat I would heat it
> up on the stove to be sure it would open, what I noticed was as it heated
> to
> temperature the thermostat would slowly open up . If it is fully opened at
> 180 than would it start to open at 150, or 160. I didn't have a
> thermometer
> at the time, I was just checking to see if it wold open and close.
>
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] which temp thermostat, 180 or 195? [message #147462 is a reply to message #147458] Sun, 23 October 2011 02:56 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
Oh Boy, Here we go again. Colonel Ken is going to kill me.

I suggest you use a 180 degree thermostat. The thermostat REGULATES the coolant flow through engine to maintain the engine temperature. If does NOT stay open after reaching 180 degrees F. I tested my current GMC thermostat in a pan of hot water on the stove. The thermostat started to open at 180. It was FULL open at 187. As the water cooled down the thermostat started closing at 185 and was fully closed at 178. That is what is does as you are going down the road.

The reason 195 thermostats were introduced was an attempt to meet 1970's emission standards. The car manufacturers found they could run at 195 and not blow up an engine before the warranty ran out. After that they did not care. Supposedly a hotter running engine emits less crap into the air.

With the advent of engine computers and oxygen sensors and catalytic converters the need for 195 thermostats went away. My 2005 GM vehicle has a 180 degree thermostat in it and you can not even buy a 195 to fit it.

I suggest that running an engine cooler has many longevity advantages. Cooler oil is a better lubricant and lasts longer. I use 1 quart of oil every 6,000 miles. Cooler transmission fluid lasts longer. (the trans is bolted to the engine and runs at similar temperatures as the engine)

You do need to maintain a minimum oil temperature to boil away any accumulated moisture but that is not a problem because the oil is heated way above the boiling point when it traverses the cylinder walls but is immediately cooled down again as it mixes in the oil pan and traverses the oil cooler in the radiator before it is reused again.

In the mountains of West Virginia I blew a big hole in my 30 year old old radiator on the way to a rally in Delaware a few years back. I blocked and epoxied a couple of the tubes and continued on my way. I was concerned about how those blocked tubes would affect the engine temperature so I removed the thermostat and continued on my trip. For the rest of the trip to Delaware climbing up hill and going down I never reached 180 degrees so that diminished capacity radiator still had enough cooling capacity to do the job. The fan never turned on.

At the rally Colonel Ken, Emery Stora, and several others helped me install a new Aluminum radiator procured from Gene Dotson. I did not reinstall the thermostat until I reached home 850 miles later.

On the return trip I could not maintain 160 degrees running on 50% antifreeze. My point on all of this is the thermostat DOES MAINTAIN the running temperature of the engine (and trans).

Use a 180 thermostat. Your engine and trans will thank you.

Notes:
1. I also have external oil and trans coolers on my GMC.
2. Dick Paterson recommends using a 180 degree thermostat.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: [GMCnet] what temp thermostat, 180 or 195? [message #147477 is a reply to message #147425] Sun, 23 October 2011 08:50 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Senior Member
Ken Henderson wrote on Sat, 22 October 2011 20:50

First off, let me state that I'm an advocate of the OEM 195*F thermostat. But I agree with the logic of having the "15*F safety margin at the bottom of the hill". So I wondered just how significant that benefit really is. Y'All check the logic and mathematics of the following:

One British Thermal Unit [Btu] is the amount of heat required to raise the temperature of 1 pound [ lb.] of water 1 degree Fahrenheit.

H20 weighs 8.33 pounds per gallon

GMCMH holds 21 qt. (call it 24 w/H20 heater) = 6 gal
6 * 8.33 = 49.98 lb ~=50 lb

1 hp = 42 Btu/min (look it up on the internet or calculate from 1 hp = 746 Watts & 1 Watt=3.412 Btu per hour)

Therefore 1 hp should raise 50 lb H20 by 42/50 = 0.84 degrees F per minute Or 1 hp should raise the temperature by 15 degrees F in 15/0.84 = 17.9 minutes

Conversely, 17.9 hp would raise the temperature by 15 degrees F in one (1) minute.

Since I'd expect the ascent of a grade steep enough to cause overheating concern to require AT LEAST an additional 18 hp, after 1 minute my "15*F safety margin" will be lost.

For that meager improvement, I'll retain the greater efficiency benefits of the 195*F thermostat. Especially since, with my AL radiator, even the Cad500, has no problem maintaining normal temperature.

JMHO,

Ken H.

Ken,

Logic is good (I haven't checked the math), but you left out the
fact that there is several hundred pounds of iron in the heat balance.

Maybe I'll come back to this when I am through playing in cold water.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: which temp thermostat, 180 or 195? [message #147480 is a reply to message #147356] Sun, 23 October 2011 09:01 Go to previous messageGo to next message
WD0AFQ is currently offline  WD0AFQ   United States
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Registered: November 2004
Location: Dexter, Mo.
Karma: 207
Senior Member
As always, you guys are good. I have no dash heat with the 180 so I switch to the 195. Then, every summer I get to thinking about those hot days and the mountains out west, and put the 180 back. One of these days I will put the 195 in and just leave it. If everything is right it should do its job.
Thanks for the discussion,
Dan


3 In Stainless Exhaust Headers One Ton All Discs/Reaction Arm 355 FD/Quad Bag/Alum Radiator Manny Tran/New eng. Holley EFI/10 Tire Air Monitoring System Solarized Coach/Upgraded Windows Satelite TV/On Demand Hot Water/3Way Refer
Re: [GMCnet] which temp thermostat, 180 or 195? [message #147486 is a reply to message #147462] Sun, 23 October 2011 09:11 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
On Sun, Oct 23, 2011 at 3:56 AM, Ken Burton <n9cv@comcast.net> wrote:

>
>
> Oh Boy, Here we go again. Colonel Ken is going to kill me.
>
>
Not hardly. If you want to destroy your engine the next time you crank it
up, that's fine by me. :-)

I'd rather get in a tire war than this one, despite Carnot.

I just wanted to see how much "hil climbing" benefit I could expect from a
lower temperature thermostat -- not much. And the absence of a clear winner
in the war indicates that it doesn't much matter longer term either.

Ken H.
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Ken Henderson
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Re: [GMCnet] which temp thermostat, 180 or 195? [message #147491 is a reply to message #147480] Sun, 23 October 2011 09:29 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
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Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
Dan,

This doesn’t make sense! Are you saying the heater does not blow hot air if you have a 180° thermostat installed you have to have a
195° thermostat installed?

If everything is right you should get heat with a 180° thermostat installed.

I suspect the water flow rate through your dash heater may be restricted.

I'd check and see if the shutoff valve opens fully and if it does I'd disconnect the inlet and outlet hoses from the heater core and
try back flushing it with a garden hose.

Regards,
Rob M.

-----Original Message-----
From: Dan Gregg

As always, you guys are good. I have no dash heat with the 180 so I switch to the 195. Then, every summer I get to thinking about
those hot days and the mountains out west, and put the 180 back. One of these days I will put the 195 in and just leave it. If
everything is right it should do its job.
Thanks for the discussion,
Dan

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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426
Re: which temp thermostat, 180 or 195? [message #147493 is a reply to message #147356] Sun, 23 October 2011 09:47 Go to previous messageGo to next message
philipswanson is currently offline  philipswanson   United States
Messages: 282
Registered: January 2004
Karma: 0
Senior Member
Even more important than the temperature is the TYPE thermostat to run. Robert Shaw used to make the best ones that allow for max volume of water to pass thru in the open position. Do not run the cheap ones you find locally. Summit and others still sell HP ones based on the old RS design. I prefer the 180 in a warm climate and would run a hotter one in very cold weather but the type is far more important.

Phil Swanson
Re: which temp thermostat, 180 or 195? [message #147511 is a reply to message #147356] Sun, 23 October 2011 12:23 Go to previous messageGo to previous message
roy1 is currently offline  roy1   United States
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
Senior Member
The difference I found between the 2 thermostats was the clutch fan came on less when using the 195 thermostat. Now that I have an Aluminum radiator and a clutch fan that likes to hardly come on at all I use the 180 thermostat.
Roy


Roy Keen Minden,NV 76 X Glenbrook
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