Str8-8-Dave

Does my 31 Buick radiator shutter work correctly?

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My 31 8-66S Special Coupe was partly restored when I got it so did not get to see some of the assembly.  One area I'm concerned with is whether or not the radiator front shutter linkage return spring is hooked up properly.  When the thermostat link pin is removed my front shutter moves wide open or to the max airflow position under the tension of the return spring.  Is that correct or should the return spring hold the shutter completely closed? 

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Interesting, mine want to close and must be held open when the stat is not working.

 

Dave

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Posted (edited)

The answer is right in the Specs and Adjustments manual on pg. 17 if I would just slow down and read.  It says under

 

"Thermostatic Radiator Shutter Control"  second paragraph

 

"When the water in the engine reaches a pre determined temperature, the thermostat begins to expand, and by means of a lever, connecting link and bell crank causes the shutters to open from their normal closed position.   As the engine temperature rises the shutters continue their opening until a water temperature of 135-145 degrees is reached and maintained.  Should the cooling effect of the air coming through the radiator tend to lower this temperature, the thermostat will at once contract,  partially closing the shutters and again raising the engine temperature.  This contraction of the thermostat is hastened by the action of a closing spring which pulls against the expansion of the thermostat."   

 

Hmmm, I should learn to read I guess...

Edited by Str8-8-Dave
edit text (see edit history)

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Well, that doesn't seem like the answer to your question. You asked, "if the pin was removed." The paragraph above is tell you how it works when it's set up properly.

That said, On my 1940 Packard, if the thermostat linkage is disconnected, the shutters remain closed. So, it is NOT a "fail safe thing." I suspect it's the same for the early 1930s vehicles with the Sylphon thermostat.

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My 1929 Cadillac fails in the closed position as well. That seems silly, especially for such a failure-prone device, but there it is.

 

I believe my 1935 Lincoln fails in the closed position as well.

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Look at it as a "feature!" If the thermo fails the overheating of the engine will let you know right away!

 

Cheers, Dave

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The fact these front shutters all fail closed is probably because the opening of the shutter through it's linkage is caused by expansion or lengthening of the thermostat.  These thermostats are filled with some alcohol or formaldehyde solution that expands as heat is applied.  The thermostat can produce pretty decent force in expanding and probably needs a little help contracting when the heat is removed.  If the spring in the shutter causes the shutter to open the thermostat will surely open the shutter but it's doubtful it has enough force to overcome the shutter spring that is trying to hold the shutter open when the thermostat starts to contract because the water temperature has dropped.

 

Whatever, I just came in from the garage for the day and my radiator and shell is now on the floor leaning up against the car.  Later today or tomorrow I will remove the radiator core from the shell and fix the shutter spring.  I also hope to get the thermostat out of the top tank to inspect it and make some kind of assessment as to whether or not it is viable.  The Buick Specs and Adjustments manual says at 135 degrees a 14lb weight should hold the thermostat in it's fully collapsed condition and at 145 degrees it should produce enough force  to lift a 14lb weight.  I'm aware you can destroy one of these if you throw it in boiling water with no load on it.  I will remove it from the water when my dial thermometer hits 150 and the thermostat will be weighted and in it's cup housing.

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Posted (edited)

Today I got the final answer on whether or not my radiator shutters were set up and working properly.  See pictures below...

Clearly not the right spring and one end of the spring is attached through a hole in the top of the shutter frame making shutter open under spring pressure.  If the spring

was attached to the pin on the right side of first picture the shutter would close under spring pressure.  I'm sure the original spring was designed to produce a certain force VS

travel curve, without an original spring installed correctly on the 2 pins the force VS travel curve won't be as designed. 

20190317_175152_LI.jpg

 

20190317_175156.jpg

Edited by Str8-8-Dave
add pictures (see edit history)

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