Bill’s Bowl Bibs Bill Bollendonk
The outside air temperature is close to 90 F, the engine temperature is about the same and you stop for some petrol and a cold drink and when you try to start the engine to get underway, it won’t run worth a diddle. This is a common problem with T cars and the solutions vary, with as many remedies as there are owners. Our MG’s are very sensitive to thermal problems, be they related to water/radiator or hot petrol. The carburetors get hot from two paths of heat, conducted and radiated.
Conducted heat from the intake manifold can raise the temperature of the carbs significantly and is the primary problem with early T types. This heat path was greatly reduced by the addition of thermal isolators between the manifold and the carbs, as found on the TF’s and is a must for anyone driving in hot weather or at high elevations such as we have here in the rocky mountain region. The addition of isolators is only part of the solution, as the radiated environment that the carbs operate in is also a major contribution to hot petrol.
There have been many ways suggested to reduce carb float bowl temperatures, most of them involving the addition of a heat shield between the manifolds and the bowls. Later MG’s came with such a shield as standard equipment and for the most part did a good job. I have fashioned several such for both my TA and TD with satisfactory results. The main drawback I have found is the difficulty associated with engine cleaning. After trying several alternate solutions, I came up with an answer that has worked well for me on the TD as it was simple to fabricate and had little cost.
I found a windshield sunscreen that my wife had discarded in the trash and thought that it might have a life after, if it could be fashioned to protect the carbs from radiated engine heat. The silver coated mylar, with a sandwich core of urethane provides an excellent thermal shield and when fashioned into bibs that surround the float bowls, greatly reduces their temperature rise. The material was cut to a width and length that fit around each float bowl and is held tight around the float bowls with a patch of velcro on the mating surfaces. A small piece of sticky back velcro hook on one side and pile on the other seems to keep them in place nicely.
I have used the bowl bibs on the TD for several years with very satisfactory results. Since they are easy to fabricate and low cost, I replace them whenever I wipe down the engine. I must point out that since the major heat source is conducted from the block, the bibs will only provide for the short petrol and drink stop as engine heat soon overcomes everything and sez “gotcha”