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MG MGA - Thermostat

Is the thermostat for a 1960 MGa 1600 the same as any MGB? Can I get one at Autozone or someplace liek that?
J Weiss

The MGA and the MGB are the same . The one I am installing is made by ITM Automotive Parts it is item # ITM 28-10071 it is a 71c or 160f stamped "Motorad" if you want to try and cross reference it at a parts place. They are generally available at 160f for hot climates, 180f for standard , and 195f for cold climates . the MGB also lists a 190f instead of the 195f
Chris Velardi

Remember that thermostats only control how cold your engine will run, not how hot it will get. I live in the semi-desert of Southern California and generally run a 190 or 195 degree thermostat for two reasons. First, the engine runs more efficiently at higher temperatures Second, the cooling system works better with with a higher differential between the ambient and the engine coolant. Oh yea, the heater works better in the winter with the higher thermostat temperature.

FYI the following is extracted the MGB Technical Thread: thermostat gasket and was posted by Steve S., Virginia, USA.

As for the thermostat, you do not have to resign yourself to the use of a conventional wax pellet thermostat. Prestone is marketing an updated version (Prestone Part# 330-195) of what is called the "balanced" thermostat that was originally designed and marketed by Robert Shaw Controls. The 3-port construction equalizes the coolant pressure from above the valve (radiator side) to the higher, pump pressure side, hence the use of the term "balanced". This allows the thermostat to open effortlessly and accurately no matter what the rate of coolant flow or the engine speed happens to be at that particular time. Non-balanced designs are prone to being forced closed when the coolant flow abruptly increases, such as during sudden increases in coolant pump speed. While its effectiveness is not immediately obvious when you first installed, its superiority does becomes more obvious while driving at sustained high speeds (70+ MPH). A balanced thermostat keeps the coolant temperature within 2 degrees compared with temperature fluctuations of up to 20 degrees with a conventional thermostat. Consequently, the operating temperature is more constant at highway speeds, and when under the strain of heavy loads, it takes longer for the inevitable rise in temperature to occur. The balanced design is such that it is not influenced by variations of coolant pressures as engine speed increases and decreases, and that means that it is better able to more accurately control the operating temperature of the engine than the wax pellet type thermostats. In conventional thermostats, the piston must make a large stroke to open the thermostat far enough for adequate coolant flow. Unfortunately, the long stroke compromises durability. In this case, the engineers achieved a shorter stroke with a uniquely-designed flange and poppet. This design increases the longevity of the thermostat, yet still allows adequate coolant circulation. The Robert Shaw design is also far less prone to failure. In other thermostat designs, the bypass valve stem is welded on. The weld tends to fail under stress. To eliminate this problem, in the Robert Shaw design, the entire copper cup and bypass stem are manufactured from a single piece of metal. By making the strut assembly from brass instead of steel provides another benefit: brass, being more malleable than steel, can be precisely formed in order to maximize coolant flow. Most manufacturers use a one-piece rubber diaphragm in order to seal the charge and drive the piston. If the rubber seal ruptures, the thermostat then fails. The piston is activated by a temperature-sensitive mixture of metallic powder and wax. Some thermostats use an all-wax charge which responds slowly to temperature changes. Other designs mix copper powder with the wax for faster response, but the copper quickly separates from the wax. The Robert Shaw design uses a process to maintain suspension of the copper powder in the wax so that the fast response will not deteriorate and the thermostat will not "stick-open" to cause the engine to run cool. The Robert Shaw design uses two separate parts: a diaphragm to seal the wax, and a stem seat or plug that drives the piston. The rubber material for each part is formulated especially to meet each part's unique requirements. Wear or damage to the stem seat still allows the thermostat to operate satisfactorily."


Lawrence Hallanger

Hi Larry, I just read your thermostat article. Could not agree more. I run a 185% unit down under in sunny Australia, 35 mpg out of the city ( imperial gallons )and no overheating, plus a hot heater in Winter. Now, where can I get one of those new fangled Yankie thermostats. They sound like an answer to a maiden's prayer ! Many thanks Sean
S Sherry

Lawrence....I really like the sound of this Robert Shaw thermostat and am now looking for one but don't think i will go to 195...stay down at 180. These units seem to go under a number of lables....
...Flow Cooler Robert Shaw 330-180
...Prestone 330-180
...Mr Gasket 4364
and cost about us$14.00 with latter showing up on US Ebay but so far have not had a reasonable delivey cost to Oz ( some wont even quote ).
Anyone know of a supplier here in Oz?
n ferguson

This thread was discussed between 26/07/2009 and 05/08/2009

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