Ted Rose--Some thoughts on why your rebuilt Stag is
overheating (assuming the radiator is really cleaned out and
timing and mixture are ok):
The waterpump. By heavy-duty I assume you mean the 12-vane
pump. Hart's Racing Service in London points out that one must
change the cover also. Apparently the 6-vane cover doesn't follow
the contours of the vanes in the newer rotors, allowing some
coolant to escape being pumped.
The thermostat. For starters, the temperature value or
rating seems to be very approximate--always quite optimistic in
my experience. If a generic thermostat is used it probably
doesn't have the secondary valve that plugs the bypass circuit,
so some flow continues to bypass the engine when the thermostat
is open. Also, if one uses a lower temperature thermostat, say
the 74 deg C. one for the TR-7 (that has the bypass valve), the
overall flow is reduced because the thermostat passage is smaller
than the Stag thermostat.
The gasket/block/head alignment. The holes in the Stag
gaskets (head) are very small--at least compared to the
corresponding passages in the head and block. The holes and
passages may not line up well, further reducing the local flow.
On another topic--Eightparts in Tucson. At the last
Portland All British Field Meet six or seven Stags turned out.
After the initial amazement of seeing so many Stags, the owners
conversation quickly and spontaneously turned to complaining
about Eightparts. Nice to hate something other than our cars for
a change. It's also nice to see some other Stag owners pop up on
the net. Good luck, Richard Hall.
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