George....
Assuming correct timing, spark plug
heat range, fuel octane, etc.......
"scaling" within water passages including
radiator over time and use will block heat transfer to the extent that
under high rpm/load conditions, the engine can over-heat even on the
coldest of days.
How often do you "backflush" using a
proprietary "cleaner" and change the
coolant? And even with good preventative
maintenance, after many many years and
seasons, "separation" of gills/rods is
bound to occur in the stock rad. causing
decay in heat transfer capability.
So...when was the last time you had the
rad. overhauled/renewed?
The heater tap at the rear of the block
should be left open year around to avoid
"hot spots" and to aid good flow/circulation throughout the system.
Keeping the heater "in" the
circuit adds a little more capacity to an
already marginal (capacity) system and
every little bit helps. Besides, the heater
is another "heat exchanger". Just close
the flaps in the cockpit so you deflect
any incoming heat "upward" to the
defrosters so you don't roast your feet!
Check the fan belt for proper tightness
as well...1/2" deflection along the longest
path.
The stock water pump pulley is intended
for lower speed operation...darting around
town and secondary roads. Over about
3,000rpm or so it begins to "cavitate" and
efficiency drops accordingly.
As Geoff pointed out, the larger 4.5" Cooper "S" water pump pulley
handles
the higher rpm range more efficiently
and in slowing the flow rate a bit, lets
the coolant spend a little more time in
the radiator for better heat "exchanging".
at highway speeds/rpms.
If the car runs more warm in traffic at
low speeds due to the larger pulley, this
may be offset by going to the "later"
multi-bladed plastic Spridget fan.
The new deep impellor alum. water pumps are more efficient at pumping
and heat dissipation. Especially those
without the cyl. head/pump "bypass"
fitting. Or, you may block the bypass
fitting with a ball bearing within the small
hose beween pump and cyl. head for
better cooling should you have a water
pump with this fitting. Just don't forget
to drill a 1/4" hole in the thermostadt
"plate" supporting the spring for some
water flow should the stadt jam in the
closed position...this will be your new
"emergency" water bypass.
A summer thermostadt rated at 68C
(approx. 170F) is helpful as well. Or
you may choose (in summer) to run
with a thermo. "blanking sleeve"....
$15 from MiniMania. Do not run without
this should you choose to run without a
themostadt...some restriction is required
for proper flow/circulation/cooling.
100% (distillled) water handles heat better
but we need pump lubrication and corrosion protection so the addition of
a proprietary product will do. Or, you can
use 25/75 antifreeze/distilled water mix
for summer use...not as good but a
definite step in the right direction for
better cooling.
You can also redirect the heater return
line back to the radiator rather than
having it go back into the water pump
to be recirculated, but this really is a
sort of last step thing which you really
shouldn't need to do consdering all the
foregoing.
Cap'n. Bob
'60 :{)
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Archives at http://www.team.net/archive/spridgets
|