1966 and later BB thermostats - NCRS Discussion Boards

1966 and later BB thermostats

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Joe R.
    Extremely Frequent Poster
    • May 31, 2006
    • 1822

    #31
    Re: 1966 and later BB thermostats

    Originally posted by Michael Johnson (49879)
    Yes, mine had that fill line, but it was about three inches below the neck. Filled to that line (I never filled to the top), it would overflow about a pint or two if the temp got above 210., and of course the heat soak after shutdown. I found by filling it 7 inches below the top it would not puke during normal driving around I do. But, all that changed when I replaced the old clunker radiator with a DeWitt's direct fit aluminum. The heating also changed of course, it doesn't overheat anymore. And I fill the DeWitt to within 2 inches of the top, it doesn't have an internal expansion tank I guess.
    Michael,

    It's a moot point for you since you now have the DeWitt's aluminum radiator. But for the possible benefit of others, I would say that seven inches is probably too far down (I can't say for sure on a L71). The mark on my L72 Is 3 3/4 " below the cap mating surface. If I filled it cold to that line, it did not puke coolant at all. So I would guess that something else was wrong with your car, maybe the old radiator was not up to snuff.

    Joe

    Comment

    • Michael J.
      Extremely Frequent Poster
      • January 27, 2009
      • 7122

      #32
      Re: 1966 and later BB thermostats

      Originally posted by Joe Raine (45823)
      Michael,

      It's a moot point for you since you now have the DeWitt's aluminum radiator. But for the possible benefit of others, I would say that seven inches is probably too far down (I can't say for sure on a L71). The mark on my L72 Is 3 3/4 " below the cap mating surface. If I filled it cold to that line, it did not puke coolant at all. So I would guess that something else was wrong with your car, maybe the old radiator was not up to snuff.

      Joe
      Yes, you are right Joe, the old one was just too plugged with mineral deposits, at least in the upper half of the radiator I could see. I had it cleaned out (rodded they told me), but that didn't get it all out I guess. Thinking about it scientifically (I'm a scientist by profession), perhaps the reason it needed 7-8 inches of expansion tank at the top (rather than the 3" or so to the Cold Fill line) is because the radiator was about half capacity from a new one because of the buildups.

      But that still doesn't answer the question of why a new one needs so much expansion tank capacity, even at 3" or so, compared to a Ford or Mopar BB radiator system where it only needs an inch or less from the neck to cold fill. There must be something very different about the 'Vette's cooling system, or the engines run lots hotter than Fords and Mopars and need more expansion room in the radiator. My '64 Dodge 426 wedge has never, ever, even in 95 degree temps, stop and go with A/C on, been over 190. I think the BB 'Vettes just had poorly designed and sized cooling systems.
      Big Tanks In the High Mountains of New Mexico

      Comment

      • Joe L.
        Beyond Control Poster
        • February 1, 1988
        • 43221

        #33
        Re: 1966 and later BB thermostats

        Originally posted by Michael Johnson (49879)
        Yes, you are right Joe, the old one was just too plugged with mineral deposits, at least in the upper half of the radiator I could see. I had it cleaned out (rodded they told me), but that didn't get it all out I guess. Thinking about it scientifically (I'm a scientist by profession), perhaps the reason it needed 7-8 inches of expansion tank at the top (rather than the 3" or so to the Cold Fill line) is because the radiator was about half capacity from a new one because of the buildups.

        But that still doesn't answer the question of why a new one needs so much expansion tank capacity, even at 3" or so, compared to a Ford or Mopar BB radiator system where it only needs an inch or less from the neck to cold fill. There must be something very different about the 'Vette's cooling system, or the engines run lots hotter than Fords and Mopars and need more expansion room in the radiator. My '64 Dodge 426 wedge has never, ever, even in 95 degree temps, stop and go with A/C on, been over 190. I think the BB 'Vettes just had poorly designed and sized cooling systems.

        Michael-------


        The cooling systems were fine. The main problem with Corvettes is the cooling "air induction system". With C2 Corvettes and some C3's, this was compounded by poor radiator support and/or fan shroud sealing. Properly sealing a C2 Corvette radiator-to-support and radiator-to-shroud, even though it results in an incorrect configuration, will improve cooling.
        In Appreciation of John Hinckley

        Comment

        • Joe L.
          Beyond Control Poster
          • February 1, 1988
          • 43221

          #34
          Re: 1966 and later BB thermostats

          Originally posted by Michael Ward (29001)
          True enough Joe, but the terminology is not mine. Better calling it an expansion tank than the more common 'surge tank'.
          Mike-----


          Actually, GM did use the term "surge tank" for the external tank used for 90-96 Corvettes as well as C5 Corvettes. These applications did use integral-to-the-radiator supply tanks which were also available separately in SERVICE, so maybe GM figured they had to use some other term for the external tank and they just weren't going to use the term "expansion tank".

          One other group of Corvette applications used both an external supply tank and an integral-to-the-radiator supply tank (although not available separately in SERVICE). Does anyone know what it was?
          In Appreciation of John Hinckley

          Comment

          • John H.
            Beyond Control Poster
            • December 1, 1997
            • 16513

            #35
            Re: 1966 and later BB thermostats

            Originally posted by Joe Lucia (12484)
            One other group of Corvette applications used both an external supply tank and an integral-to-the-radiator supply tank (although not available separately in SERVICE). Does anyone know what it was?
            Joe -

            '53-'54 (and a few '55) with six-cylinder engines.
            Attached Files

            Comment

            • Joe L.
              Beyond Control Poster
              • February 1, 1988
              • 43221

              #36
              Re: 1966 and later BB thermostats

              Originally posted by John Hinckley (29964)
              Joe -

              '53-'54 (and a few '55) with six-cylinder engines.
              John------


              Yes, but I was referring only to V-8 applications BUT I should have said that. So, if one includes all Corvette applications there are the 53-55 six cylinder applications you mentioned PLUS one other group of applications.
              In Appreciation of John Hinckley

              Comment

              • Michael W.
                Expired
                • April 1, 1997
                • 4290

                #37
                Re: 1966 and later BB thermostats

                Was there not a very early 60's config that was quite unusual? Separate coolant recovery tank on top of the radiator IIRC.

                Comment

                • Joe L.
                  Beyond Control Poster
                  • February 1, 1988
                  • 43221

                  #38
                  Re: 1966 and later BB thermostats

                  Originally posted by Michael Ward (29001)
                  Was there not a very early 60's config that was quite unusual? Separate coolant recovery tank on top of the radiator IIRC.
                  Mike------


                  That was used on early 60's with aluminum radiator. The tank was, basically. a separate supply tank that was included with the radiator unit. The aluminum radiator had no other tanks.
                  In Appreciation of John Hinckley

                  Comment

                  • Ronald L.
                    Extremely Frequent Poster
                    • October 18, 2009
                    • 3248

                    #39
                    Re: 1966 and later BB thermostats

                    OK - bac to the thermostats.

                    I now ahve the 180 degree robert shaw part.

                    We know the water boils at lower temperatures with increased elevation. Here in the low lands of the Motor City, my thermometer registers 210 when the water is boiling and this is on several verifications over the past 6 months.

                    So...
                    Recall that 180 degree STANT part did not open until 200 last month, well this month it still does not open until 200 degrees.

                    The Robert Shaw part, on the box 180 and stamped 180??? It "starts" to crack at 190, but is not open to 200 degrees.

                    What part of Issac Newtons Physics do these suppliers don't get?

                    Comment

                    • Michael W.
                      Expired
                      • April 1, 1997
                      • 4290

                      #40
                      Re: 1966 and later BB thermostats

                      I think Duke covered that in post #10

                      Comment

                      • Duke W.
                        Beyond Control Poster
                        • January 1, 1993
                        • 15671

                        #41
                        Re: 1966 and later BB thermostats

                        Originally posted by Ronald Lovelace (50931)
                        OK - bac to the thermostats.

                        I now ahve the 180 degree robert shaw part.

                        We know the water boils at lower temperatures with increased elevation. Here in the low lands of the Motor City, my thermometer registers 210 when the water is boiling and this is on several verifications over the past 6 months.

                        So...
                        Recall that 180 degree STANT part did not open until 200 last month, well this month it still does not open until 200 degrees.

                        The Robert Shaw part, on the box 180 and stamped 180??? It "starts" to crack at 190, but is not open to 200 degrees.

                        What part of Issac Newtons Physics do these suppliers don't get?
                        At sea level with a 15 psig pressure cap a 50/50 glycol/water blend boils at about 265F, so either your pressure cap is not to spec or your temperataure measurments are incorrect.

                        With a 180 degree thermostat and a 15 psig cap, the normal operating temperature range of the engine is 180-230F. That still leaves 35 degrees margin to boiling. Temperatures at the upper end of this range are normal in low speed driving in hot weather.

                        Duke

                        Comment

                        • Ronald L.
                          Extremely Frequent Poster
                          • October 18, 2009
                          • 3248

                          #42
                          Re: 1966 and later BB thermostats

                          I saw that, but, the one in my car, very old, opens from 175 and is full open at 180. So with these new parts I'd be adding 20 degrees to the open temperature.

                          Comment

                          • Joe L.
                            Beyond Control Poster
                            • February 1, 1988
                            • 43221

                            #43
                            Re: 1966 and later BB thermostats

                            Originally posted by Ronald Lovelace (50931)
                            I saw that, but, the one in my car, very old, opens from 175 and is full open at 180. So with these new parts I'd be adding 20 degrees to the open temperature.


                            Ronald-----


                            It could very well be that the old one has DEGRADED to what you find and just because, coincidentally, it shows what you expect, you figure it's the way it always was.
                            In Appreciation of John Hinckley

                            Comment

                            • Ronald L.
                              Extremely Frequent Poster
                              • October 18, 2009
                              • 3248

                              #44
                              Re: 1966 and later BB thermostats

                              No problem reading the thermostat and the radiator pressure cap is not the question nor the issue hrere... my thermometer shows 211 in pure water boiling steady state at 500 feet above seal level. Nothing wrong with the thermometer or the user.

                              These are thermostats new out of the box.

                              One thing - the 1970's part book I have shows a 170 degree thermostat for these big block cars, so if we followed that logic, that is why the thermostat in the car is full open at 180.

                              By the way... I had that one out and measured it, that is why I know exactly when it starts to crack open and then when it is full open. and those tests were re run several times - each.

                              Comment

                              • Michael J.
                                Extremely Frequent Poster
                                • January 27, 2009
                                • 7122

                                #45
                                Re: 1966 and later BB thermostats

                                Originally posted by Ronald Lovelace (50931)
                                No problem reading the thermostat and the radiator pressure cap is not the question nor the issue hrere... my thermometer shows 211 in pure water boiling steady state at 500 feet above seal level. Nothing wrong with the thermometer or the user.

                                These are thermostats new out of the box.

                                One thing - the 1970's part book I have shows a 170 degree thermostat for these big block cars, so if we followed that logic, that is why the thermostat in the car is full open at 180.

                                By the way... I had that one out and measured it, that is why I know exactly when it starts to crack open and then when it is full open. and those tests were re run several times - each.
                                Don't know what to say about your tests in the pot of water, but I have a 180 Robertshaw FlowCooler and it opens at 180 in my car. I can see that from the temp gauge which is pretty accurate.
                                Big Tanks In the High Mountains of New Mexico

                                Comment

                                Working...
                                Searching...Please wait.
                                An unexpected error was returned: 'Your submission could not be processed because you have logged in since the previous page was loaded.

                                Please push the back button and reload the previous window.'
                                An unexpected error was returned: 'Your submission could not be processed because the token has expired.

                                Please push the back button and reload the previous window.'
                                An internal error has occurred and the module cannot be displayed.
                                There are no results that meet this criteria.
                                Search Result for "|||"