.
One More Article on Keeping Our Cars Cool
Or
Even Mechanics Can Have Overheating Problems
After experiencing overheating and vapor lock in my MGA
during 100 degree plus weather earlier this year, I was determined to finally
defeat this recurring problem. Though these procedures were performed on a specific
MGA, they should be applicable to any other car experiencing overheating/vapor
lock problems.
I started with the vapor lock problem. Vapor lock is caused
by engine heat vaporizing fuel either in the float bowls or fuel lines. The
result is the engine won’t run until the fuel cools and returns to a fluid
state. The engine overheating aggravates vapor lock. MGAs have a heat shield
behind the SU carbs, but it is minimal protection, even when the original heat
insulating pads are in place. I was able to find an aftermarket manufacturer
making a stainless steel heat shield that had a modern insulating pad that
covered the entire back side of the shield instead of two small pads on either
end. There are also thermo sleeves available that will slip over and insulate
fuel lines. I didn’t use these because I was counting on making the engine run
cooler to control vapor lock.
The overheating engine must be attacked on several fronts.
If you correct one problem in the system you may only reduce engine temperature
a few degrees, but as you work through the entire system, a few degrees here
and a few there will add up to a cool running engine. On my engine I started
with the radiator. I had purchased a new radiator a few years ago because it
was higher efficiency but it wasn’t the highest efficiency. I took the radiator
and had it re-cored with the highest efficiency core available. This was more
expensive than a new radiator but proved to be worth the money. Next I changed
the water pump to a new unit. The old pump had been on the car for over five
years and wasn’t leaking but I wanted to be sure I was getting full
circulation. I also installed a new 160 degree thermostat. MGAs have a small
front grill and air flow is minimal. My MGA had an oil cooler installed in
front of the radiator so in order to increase air flow, I moved the cooler to
below the front shelf. Next in order to get even more air flow, I installed a
MGB seven bladed fan in place of the original six blade fan. The final puzzle
piece was the radiator shroud. I had an aftermarket shroud installed for years
but was never happy with the way it fit. It is made from plastic and when the
radiator is tightened in place it would pooch out in the middle (not fit flush
against the radiator). This allows air to be pulled from the engine compartment
instead of being pulled through the radiator. This time I used heat resistant
tape to seal the shield to the radiator.
The bottom line, on a recent driving trip on a 98 degree
day, the water temperature while driving was 165. At idle the temperature would
go to 175. The temp never went over 185.
Questions or comments can be directed to
ron@5RRestorations.com or call
281-346-2417.