[TR] Water pumps.

[Randall]

> It's got me curious now, though...if I had any spare time, it would be
> interesting to model heat transfer in a Triumph system sand see where
> the bottlenecks are.  (My money is on plugged radiators).

FWIW (not much), my TR3/A overheating problems have mostly been traced back
to a defective (but not leaking) radiator.  I had an original radiator where
the fins were apparently not in good thermal contact with the tubes; having
it recored made all my overheating problems vanish like magic.  It had been
rodded out, so I don't think plugged tubes were an issue.

Second time around, it appeared the problem was that the inside of the tubes
were coated with a muddy substance, likely a mixture of rust particles and
stop-leak.  The radiator shop swore it "flowed fine", but when I finally
insisted that they rod it out, they couldn't get the rods through the tubes!
Once again, having it recored made a world of difference.  I can't prove it,
but IMO the problem was not lack of flow, but rather that the "mud" was
acting as an insulator.  The water coming out was almost as hot as the water
going in, which is the opposite of what I would expect if the flow were not
high enough.

But with a stock system in good condition, IMO airflow is the most common
limiting factor.  My experience has always been that the temperature will
creep up in heavy stop-and-go traffic or extended idling.  Getting more
airflow at idle, with either an electric fan or a more aggressive mechanical
fan, seems to be the sure cure for that issue.

Worth noting, in case anyone still doesn't know (and is still reading this),
that there were two other factory fixes for air flow on the TR3A/B that some
cars may be lacking.  There is supposed to be a cardboard shroud that fits
behind the apron and directs air into the radiator, which was not fitted on
the first twenty thousand or so "wide mouth" cars (but is a factory-approved
retrofit).

The other change was to widen the slots in the 3A/B grille.  Many
aftermarket grilles are not made to the updated specification.  Sorry I
don't have the link handy, but details can be found on TeriAnn Wakeman's web
site.

-- Randall