Moss Motors, Ltd

To solve an overheating problem with my 58 MGA with a .030 over rebuild and compression upgrade to 9.8 - 1, I installed a recored radiator with about 20% more cooling capacity and the 16 row oil cooler.  The engine now runs around 185 - 190 deg on the open road with the temperature going up to maybe 200 - 210 on longer hill pulls.  In order to make the thermostat more effective and regulate the temperature better, I think to use the 20% more capacity in the radiator the water pump needs to turn about 20% faster also.  That way more cooler fluid from the radiator will be circulating throught the engine and the thermostat will be more effectively used to stop down, or open up, to help the temperature stay at a steady reading.  In other words, with more cooling capacity in the radiator, wouldn't it be more effective if the water pump turned faster to better use the extra capacity?  If this theory is all true, and I am not sure it is, the question now:  Does anyone know of a water pump pully that will fit the MGA engine that is smaller in diameter, to turn the pump 20% faster.  I have not seen any catalogs, including Moss, that even list water pump pulleys for sale, so maybe one will have to be fabricated by a machine shot to work. For racing purposes everyone wants to slow the pump down with larger pulleys, so maybe none are available.  Any help would be appreciated.

Dar

The MGA pulley is pretty unique. I'm not aware of any alternatives to the original repro that is on the market. Another alternative would be to open up the front of the block face to accept the late model 5 Main water pump which has a larger impeller. This is a fairly common racing modification. You will have to also use the later pulley to match the different flange location. This also lets you use the later 1973-75 MGB plastic cooling fan which is a lot more efficient. You have to be careful about clearance to the radiator, but it should fit.

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Kelvin Dodd
Global Sourcing Engineer
Moss Motors, Ltd.
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Disclaimer: Working on automobiles is inherently dangerous. Moss Motors, Ltd. is not liable for injury or damage due to incorrect installation or use of their products. All products are sold with the understanding that the safe and proper installation and use of the products is the customer’s responsibility. Follow factory workshop manual procedures and instructions, but use current shop safety standards and common sense. Some tasks will require professional advice or services which Moss Motors cannot provide.

By theory, increasing the diameter of the pulley will slow the coolant down, allowing the radiator more time to cool the liquid.

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Dar,

 I just saw you post after reading the single best cooling article about Little British Cars.  The article is about the Tiger; but, it applies to all cars (especially LBC's).

 Take a look:  http://www.teae.org/cooling/cooling_article.html

 
Hope this helps,

 Lamar


 

Lamar-

Wow-  That was a great article and I am saving it for anyone in my MG club to read that has heating problems.  I did not go through any test as they did with the Sunbeam Tiger, but I came to about the same conlusions.  To close the story of my 58 MGA and the heating problem, I used a water pump pulley from an MG Midget (the original steel one-grove pulley) which is about 15% smaller than the MGA pulley, yet it has the same registration so the fan belt lined up perfectly with the generator pulley and the crank pulley.  I used a new water pump and had the pump snout turned down so the smaller pulley would fit over the snout and redrilled and taped the nose so the standard MGA fan would attach. Now the fan and pump turn about 15% faster than the original pump and fan and I believe the cooling problem is solved.  When the weather is better in the spring I will give it a hard road test and see if the problem is solved. I believe, as the article stated, moving more air is the solution, and the smaller pulley not only moves more air, but more water to take advantage of the 20% increased capacity of the new radiator. Thanks for the great article.

Dar

Dar:

Let us know how it turns out. It's interesting that the Midget pulley had the same belt line up. Something else to put into the tech library.

Lamar:

Thanks for the link, good info!

 

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Kelvin Dodd
Global Sourcing Engineer
Moss Motors, Ltd.
Helpful Links:
Code of Conduct
FAQs

Disclaimer: Working on automobiles is inherently dangerous. Moss Motors, Ltd. is not liable for injury or damage due to incorrect installation or use of their products. All products are sold with the understanding that the safe and proper installation and use of the products is the customer’s responsibility. Follow factory workshop manual procedures and instructions, but use current shop safety standards and common sense. Some tasks will require professional advice or services which Moss Motors cannot provide.

Kelvin: 

Finally made it back from Florida after spending the winter there.  Have had a few nice weekends here now and had a chance to get the MGA out for some serious hard driving to check the cooling.  I have driven it hard, driven it slow through towns, let it idle for long periods, and have not had a problem at all with cooling. The recored radiator is a now a 3-core unit but the tanks available on your radiators you now sell can hold the 3-core units as repalcements for the 2-core units originally in them.  What solved the problem, as the article said, was more air passing through, along with the increased coolant capacity.  Yes, the steel, single grove pulley, from the Midget fits the belt registeration perfectly when the water pump snout is turned down to fit the smaller pulley.  With the 180 deg  thermostat installed, the water temperature never leaves 180 deg once the total coolant volume reaches steady state temperature. Prior to reaching 180 deg throughout the entire system, the thermostat opens and closes allowing the coolant to vary about 5 deg about the 180 deg point, as read on the coolant temperature gauge.  Once equilibrum is reached, it stays at a steady 180 deg so it is working just as it should. One thing that is a certainty....if you modify the engine to put out more power, more heat is generated, and that has to be accounted for with more cooling capacity.  Maybe this will help anyone having MGA cooling problems.

 

Dar