more V8 cooling tips
Lothar Taverne (Glacier White 5001) from Vienna
has a Costello MGBGTV8. This note has been prepared with help from our Swiss member
Tom Studer (Damask 0109).
have been several contributions from members on this well known problem with MGBGTV8s.
I would like to show another approach. It is not only the cooling system that
determines the temperature of the engine but also the fuel/air mix plays a major
part too. Every combustion engine that runs on fuel works best when the fuel and
air are in the proportion 1:15, although an engine will run up to 1:6 (which is
much too rich) and down to 1:18 (which is far too lean). By running on 1:18 you
would save considerably on fuel, but it raises the temperature in the cylinder
head and therefore loads the water and oil circuits. To get the highest output
from an engine, it is essential to run on the right mixture - which is a little
enriched - and to maintain this mixture constantly so the fuel and air get mixed
which improves the evaporation of the fuel.
if you drive the car hard on a lean mixture, the temperature of the engine will
rise even more, but there is a way to find out whether the mixture is too rich
or too lean. It is advisable to have a second person to assist with a fire extinguisher
- don't worry. The only other thing you need is a spray phial which resists fuel.
Sprinkle a little fuel in the air cleaners and if the mixture is not too rich
enough the engine speed will increase or it will decrease if it is too rich. If
it stays constant, the mixture is fine.
that the mixture has been adjusted there are a few other things which can be improved.
to Contents listingAdjusting
the temperature at which the fans cut in. Firstly when the original thermostatic
switch comes in too late, the effect is the accumulated heat cannot be cooled
down satisfactorily. You can fit a Kenlowe switch and with this you can vary the
temperature at which the fans cut in. By varying the "cut-in" temperature,
you can find the best temperature at which the fans should come on.
of the bimetal "cookers". You can remove the "cookers"
or "claws" which are the air intakes for the circular air cleaners on
the standard set up.
size. Another way of improving cooling is to improve effectiveness of the
fan blades. Kenlowe do a 10 blade fan instead of the four blades on the standard
fan. Unfortunately the diameter of the Kenlowe fan is too large, so the 10 blades
have to be cut down. Even after cutting down the blades, each has about 40 sq
cm more surface. It is also advisable that the fan blades are located as close
to the radiator matrix as possible. When cutting down the blades, considerable
care will be needed to ensure the fan unit is balanced to avoid vibration in operation.
in the radiator. It is possible to fit more segments in the radiator water
cooler box when a rebuild becomes necessary.
ignition timing. It is essential that the ignition timing is checked because
this also influences the temperature of the engine. Check also the distributor
shaft and the drive for wear which has an effect on the timing.
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