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MGB THERMOSTAT

Posted by Naomi 
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Naomi Avatar
Naomi C
Between Greensboro and Roanoke, USA   usa
1964 MG MGB "Kirby"
1979 MG MGB "Bandit"
1980 MG MGB "Robbie"
1995 Mazda Miata Special Edition
2003 Jaguar S-Type

Two questions but first a comment. The hubby said we needed to put in a 160 degree thermostat for summer operation and the 180 for winter. I picked up the 160 degree thermostat a short while ago. Now the questions:

1. Is the hubby right? Our Haynes Repair Manual says a 180 degree thermostat is the correct one for my car but Advance Auto did have a 160 to my surprise.

2. The thermostat is sold by the brand name "Stant". The guy behind the counter showed me on his PC that they had three that would fit my car, all made by "Stant". One was $3.98, the second was $5.98 and the third was $6.98. He recommended, and I bought, the $6.98. Question: Why do they have three different prices----is one just plain ole bad, the second between bad and good and the third the best they make? I can't imagine them advertising that one just ain't no good.

Your comments please!






"1964 MGB" (Kirby) All original pull handle MGB, 3 main, with overdrive, but a daily driver with all the dents and dings to prove it -- Titled in 1965~~

"1980 MGB" (Robbie) Even though it's a RB it does have overdrive, a Weber Carb, and is my favorite MGB. We have logged thousands of happy miles together ~~

John D. Weimer Avatar
Cape Girardeau, MO, USA   usa

Chaz is right, but I run a 180 in mine all the time; I'm right too. Some guys run a 190 in Winter, they are right too.

I've sold Stant, Bridgeport, Robertshaw, Dole, and other top name thermostat. It doesn't make a bit of difference which price range you buy in it's a roll of the dice every time as to whether you get a good one or not. That littl ecopper pill in the middle with the special wax int it is all that counts for anything. If it's good the thermostat is good no matter what it cost or what it lookslike otherwise.

The guy at Advanced Auto is right. Buy the $6.95 one and feel safe, or you could pay him $26.95 and feel super safe.......... Until the damned thing screws up.





My Motto: Clean Body, Clean Mind...................... Take Your Pick.

JDW!!
#3
Victoria, BC, Canada   can

Do you mean 'Bill is right', this isn't Kim, you know!! I run 160 to 165 unless it is computer controlled!! Then you have to run what they say!!

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John D. Weimer Avatar
Cape Girardeau, MO, USA   usa

You're right too!!! About the only ways you can go wrong with a thermostat is to not put one in, or not put the recommended one in a computer controlled car. The rest is personel preference. There is NEVER a warranty saying a thermostat is good, only that they will replace it within their designated time limits if it's bad. There is also no limit on how long a good thermostat can stay good. The the thermostat in the Tank engine I took out was 25 years old and still good, I have a new one since the swap, it's only 21. The one in my Saab was 17 when I swapped the car. So long as the seal holds on that little wax filled pill holds that thermostat is as good as new.





My Motto: Clean Body, Clean Mind...................... Take Your Pick.

Naomi Avatar
Naomi C
Between Greensboro and Roanoke, USA   usa
1964 MG MGB "Kirby"
1979 MG MGB "Bandit"
1980 MG MGB "Robbie"
1995 Mazda Miata Special Edition
2003 Jaguar S-Type

Okay John I'm gonna play the dummy. My Haynes Repair Manual says a 165 degree thermostat for early MGB and a 180 degree for late MGB. It doesn't offer the latitude you and the hubby agree on. My question: Why does the manual not recommend the 160 degree you and the hubby agree on for summer use? No doubt you two are right but I don't understand. Kinda like 20W50 oil. Why not 5W30 like most cars use? Honestly I just want to understand.






"1964 MGB" (Kirby) All original pull handle MGB, 3 main, with overdrive, but a daily driver with all the dents and dings to prove it -- Titled in 1965~~

"1980 MGB" (Robbie) Even though it's a RB it does have overdrive, a Weber Carb, and is my favorite MGB. We have logged thousands of happy miles together ~~

Rob Edwards Avatar
Rob Edwards
Raleigh, North Carolina, USA   usa
1951 MG TD MkII "TDC6000"
1969 MG MGB "182608"
1969 MG MGC GT "8806"
1969 MG MGC GT "Rcedward"
1970 MG MGB GT "Donor"   → more

Naomi,
I'll muddy the waters a little more -- I run a 195 year-round (mostly because I want the heat in the winter and I'm a lazy sod and don't want to change it twice a year). I have no problems with overheating. Granted, I'm running a Robertshaw High Performance tstat (AutoZone, about $6 -- lie to them and tell them you want it for a small block Chevy. At least around here, if I say "MG," they say "Who made that?" The Robertshaw number for a 180 is 330-180, and for a 195 is 330-195.)

Here's the exact same tstat reboxed by Mr. Gasket and sold by Summit Racing:
http://store.summitracing.com/partdetail.asp?part=MRG%2D4364&view=257#largerimage





--
Rob Edwards
Raleigh, NC
http://www.mgcarz.com

If you're in NC, check out the North Carolina MG Car Club!
http://ncmgcc.org

Naomi Avatar
Naomi C
Between Greensboro and Roanoke, USA   usa
1964 MG MGB "Kirby"
1979 MG MGB "Bandit"
1980 MG MGB "Robbie"
1995 Mazda Miata Special Edition
2003 Jaguar S-Type

Well Rob you've done it. Now all is "muddy" to me. I don't understand why they make them for different temperatures, the manual identifies one temperature as the correct one for my MG, and then the hubby and JW agree that a different temperature will work. On top of that you now say you use a higher temp one. I'm sure not a mechanic but it doesn't make any sense to me.






"1964 MGB" (Kirby) All original pull handle MGB, 3 main, with overdrive, but a daily driver with all the dents and dings to prove it -- Titled in 1965~~

"1980 MGB" (Robbie) Even though it's a RB it does have overdrive, a Weber Carb, and is my favorite MGB. We have logged thousands of happy miles together ~~

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Rob Edwards Avatar
Rob Edwards
Raleigh, North Carolina, USA   usa
1951 MG TD MkII "TDC6000"
1969 MG MGB "182608"
1969 MG MGC GT "8806"
1969 MG MGC GT "Rcedward"
1970 MG MGB GT "Donor"   → more

Well, as I said, I run the hotter one so that I get better heat in the winter, and I discovered that it made no difference in operating temp in the summer. My theory (and it's only a theory) is thus: The temperature at which the engine will run is controlled by the balance between the heat generated by the engine, and the capacity of the cooling system to shed heat. A thermostat works by "switching the cooling system on and off", thereby controlling the balance between the two. Ideally, you'd want excess cooling capacity so that you could deal with extreme high ambient temp/high load situations. But the side effect of that is that under normal conditions, the car would tend to run too cool, so in a sense the thermostat regulates how much of that excess capacity gets used.

However, if the balance between heat generated by the engine and maximum heat able to be shed by the cooling system means that the engine will run at, say, 200 degrees, then whether the thermostat opened at 165 or 180 (or 195) makes no difference -- at 200 degrees they're all open.

My experience is that, if we call the temperature at which the thermostat opens the "regulated" temperature, in warm weather, my car always runs above regulated (at +/- 200), regardless of the thermostat's opening temp.

I do think that the Robertshaw thermostat helps, because if you could see one open, you'd see that it has a much larger open area than a conventional one. I might very well find that with a conventional 195 deg theremostat, my car might run unacceptably hot due to less coolant flow.

Also, I like to run my engines a little hotter than most folks, because I believe it makes more power, not less. Here's what Smokey Yunick has to say:
Quote: " It is easy to see how overheating can be a problem, but I think some racers overlook the fact that it is possible to 'overcool' the engine. Some guys go to great lengths to keep the engine temperature down to 180 degrees. And, though the engine doesn't overheat, they don't realize that they're putting energy (heat) into the cooling system that could be used to produce power at the crankshaft.
Running the engine at 180 degrees will drop the overall horsepower by 2%-3%. For max power the cooling temp should be at least 200 degrees, and you should have at least 25 pounds of pressure in the system...."

(I do [bold]not[/bold] run my cooling system at 25 psi! I think he's concerned about boilover under race conditions and so says run high pressure...)

Hope I didn't confuse you further!





--
Rob Edwards
Raleigh, NC
http://www.mgcarz.com

If you're in NC, check out the North Carolina MG Car Club!
http://ncmgcc.org

Don

...the GT runs a 195 year round, no problems. It'll show ~210 on the daily hill climb and 200 in heavy traffic during the summer. Won't get above 170 in winter...

tony barnhill Avatar
Tony Barnhill
Gurley, Alabama, USA   usa

Only time I've ever changed thermostats during year was once in winter somewhere in Missouri when I used the MG to make a long, fast run from Kansas to Mississippi for my step-father's open heart surgery....had run most of the evening across the flatlands in blowing snow...cold as you-know-what...couldn't get temp up enough to warm inside of car...cardboard in front of rad didn't work....pulled into a filling station late at night, bought a 'hot' thermo off his rack (not correct one for MG but who cared at the time), installed it myself as he didn't have a mchanic on duty, & got engine hot enough to warm air so defroster would work & I could keep tolerably warm....

....most MG books talk about 2 different thermostats - 1 for cool weather, 1 for warmer weather.....however, its not necessary unless you're in extreme climes or slow stop & go city driving....

....&, I believe, earlier heads had different water port/flow than later heads....Tom?





Tony Barnhill
Supplying Member: Used Parts for All MG's ~ New Parts for all LBC's
MOSS Distributor & VICTORIA BRITISH Dealer


MG's? YOU NAME 'EM, I GOT 'EM!
http://www.theautoist.com

--------
In addition to the MG's listed on the left:
1971 VW Karmann Ghia
1972 Norton 750 Commando Motorcycle
1973 VW Bug
1982 Mercedes 380SL
1985 Jaguar XJ6

jerry harrington Avatar
Jerry Harrington
north east, USA   usa

toss in the 3 98 160 and then cut a piece of cardboard half the height of the radiator for the winter and duct tape the cardboard into place for the winter. less hassle

wpetski Avatar
Willie Poetschke
Plano, TX, USA   usa

Reading all the pros and cons about which degree (160 v 190) and overheating v overcooling reeminds me of the very detailed discussion as to why one should use the thermostat with a sleeve block/unblock the bypass port at the proper time, i.e., so that hat colant will got to the radiator instead back thru the head, causing overheating. The thermostat is designed to control cool it lets the coolant get.
I saw only one comment that was inline with Muenchausen's Garage site, (click on MGB Cooling Experience) at: http://cibolas7.net/12299.html

It makes clear the whole concept of controlling overcooling by the radiator.

wpetski Avatar
Willie Poetschke
Plano, TX, USA   usa

I forgot to include the piece that gave Bob Muenchausen credit for photo of Prestone's sleeve thermostat. The RobertShaw Controls' Balanced Flow thermostat (the design was purchased by Cooper Automotive) is sold under the Prestone name, part numbers: 330-195, 330-185, & 330-160.

The piece it at: http://mgcarz.com/thermoststs.html

This is the article that really explains the myths of cooling/overheating.

wpetski Avatar
Willie Poetschke
Plano, TX, USA   usa

When I finish upgrading/restoring my 73 MGB Roadster, (including getting rid of rust & gunk inside of the head and block) I plan to use a 10# radiator cap and a #330-195 sleeved thermostat. The higher flow pressure can collapse a bellows thermostat. The "fail-safe-open" position will prevent complete and dangereous overheating.

Original MG 1800 engines, I believe, should stay with a 7# radiator cap and a 180/185 degree thermostat.

MOSS sometimes have the proper thermostats.


gsj28 Avatar
Gary Jackson
Tracy, California, USA   usa
1965 MG MGB
1972 MG MGB GT
1972 MG MGB GT

Also, a lot of cars used hotter thermostats for emissions reasons (Along with a hotter radiator fan switch). That could be the reason for the different temps in the early and late MGB.

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