1966 and later BB thermostats

[Ronald L.]

I know we've touched on this somewhat before, but, a 180 degree thermostat, Stant, supposedly the original manufacturer, at what temperature is it supposed to start to open and at what temp is it full open?

I have yet another 180, stamped as such, new, that does not get full open, not even close to open until 200 degrees - it is full open at 200.

Given that this is a 427 with its known hot-running characteristics, is this an issue?

Will it break in and open at lower temperatures once is use? I think not.

The one that is in the car, very old too, unknown supplier, I tested and it opens full at 180.

[Joe L.]

Re: 1966 and later BB thermostats

I know we've touched on this somewhat before, but, a 180 degree thermostat, Stant, supposedly the original manufacturer, at what temperature is it supposed to start to open and at what temp is it full open?

I have yet another 180, stamped as such, new, that does not get full open, not even close to open until 200 degrees - it is full open at 200.

Given that this is a 427 with its known hot-running characteristics, is this an issue?

Will it break in and open at lower temperatures once is use? I think not.

The one that is in the car, very old too, unknown supplier, I tested and it opens full at 180.

Ronald------


The original thermostats were not manufactured by Stant. In those days, I believe that most, if not all, GM thermostats were of internal GM manufacture.

Keep in mind that a thermostat only controls the LOWEST temperature at which an engine will operate, not the highest. Nevertheless, I would want a thermostat that was full open at 180 degrees. Is the one that you have that opens at 200 degrees actually STAMPED as a 180? It might actually be a 195. These were actually used on 1966-67 with K-19.

[Wayne M.]

Re: 1966 and later BB thermostats

.....The original thermostats were not manufactured by Stant. In those days, I believe that most, if not all, GM thermostats were of internal GM manufacture.....

Ron -- this is probably the look of the TFP thermostat installed in 1966, although the part # would have been probably 3136185 or 3156280 with 108-P on the box, and 180 degrees stamped on the poppet end. The HRD stamping is for Harrison Radiatior Division (of General Motors).

[Ronald L.]

Re: 1966 and later BB thermostats

I remember those guys from upstate NY.

OK to Joe's point, yes both were stamped with 180, and cracked at about 190 to full open at 200. I'm just going to pull the old one and use that. Enough of this stuff from stant.

[Joe L.]

Re: 1966 and later BB thermostats

I remember those guys from upstate NY.

OK to Joe's point, yes both were stamped with 180, and cracked at about 190 to full open at 200. I'm just going to pull the old one and use that. Enough of this stuff from stant.

Ronald------

I would recommend using a Honeywell-Robertshaw 330-180 if you can find one.

[Jim T.]

Re: 1966 and later BB thermostats

Ronald------

I would recommend using a Honeywell-Robertshaw 330-180 if you can find one.

Joe I still have a couple NOS GM 180 thermostats I have had for 20 years, do you think the Honeywell-Robertshaw thermostat if I can find one is better?

[Ronald L.]

Re: 1966 and later BB thermostats

All I can say from the day, 35 years ago is that we never worried about this temp thing, nor tested them. The only concern were the ones that let go and blew out your housing making a mess of the engine compartment.

This stant is the big box Corvette item and has USA not it, not China.

[Joe L.]

Re: 1966 and later BB thermostats

Joe I still have a couple NOS GM 180 thermostats I have had for 20 years, do you think the Honeywell-Robertshaw thermostat if I can find one is better?

Jim------


Yes, I do.

[John H.]

Re: 1966 and later BB thermostats

Ron -

Here's a Robertshaw #330-180 on the right, and a typical OEM-type thermostat on the left.

[Duke W.]

Re: 1966 and later BB thermostats

The rated temperature of automotive thermostats is the temperature that they begin to open with a few degrees tolerance on either side.

Full open is not achieved until 20-30 degrees above the rated opening temperature.

That's how they work.

Duke

[Jack C.]

Re: 1966 and later BB thermostats

What would be the advantage/disadvantage of not using a thermostat at all (vs. the recommended temp) if you were concerned of over heating or a sticking thermostat?

[John H.]

Re: 1966 and later BB thermostats

What would be the advantage/disadvantage of not using a thermostat at all (vs. the recommended temp) if you were concerned of over heating or a sticking thermostat?

You do NOT want to run without a thermostat. It will take a LONG time for the engine to come up to normalized operating temperature (increasing wear), and the thermostat is a designed orifice area that modulates coolant flow to maintain minimum coolant temperature.

[Jack C.]

Re: 1966 and later BB thermostats

Thanks John.

[Joe R.]

Re: 1966 and later BB thermostats

Ron and Jim,

Here's one place to get the Robertshaw thermostat:

http://www.summitracing.com/parts/BRA-330-180/

Also, the hot running big block myth has been dispelled on this board at least once. I'll see if I can find the thread I'm thinking of.

Joe

[Michael J.]

Re: 1966 and later BB thermostats

Ron and Jim,

Here's one place to get the Robertshaw thermostat:

http://www.summitracing.com/parts/BRA-330-180/

Also, the hot running big block myth has been dispelled on this board at least once. I'll see if I can find the thread I'm thinking of.

Joe

This is where I got mine, and it works great. However, a hot running (210 degrees+ and over 230 in stop and go driving) BB is not a myth but a very common occurrance. It can be solved, but take it from a person who did about a dozen things (many suggested by Duke) to fix it, it takes much time and work to solve the hot running BB.