Bob---The one thing that's missing from your response is what kind of
"new cam" did you install?
Poor vacuum isn't necessarily a reason for an engine to run hot, but
TRiumph recognized that, (for emissions considerations,) running their
ignition timing at 4 degrees ATDC for long idling periods was a problem.
They incorporated the vacuum bi-pass in the radiator hose so it
interrupted the retard at the distributor, when the coolant reached a
certain temp, which allowed the idle (and water pump) to speed up thru
ignition timing advance.
What is your vacuum reading at idle? Stock cams usually produce around
18-20 inches. Performance cams can send a vacuum signal of 15 inches or
less.
I can't see where a proper valve adjustment could lend itself to
increased idle temperatures. Most likely it's in the head work and/or
the cam work. The rad is easy to pull but premature at this time. Run
with no more than a 50/50 mix with the anti-freeze/water.
Finally, you may not even have a serious situation that needs
correcting. Merely one that must be paid when deviating from stock
equipment, as most of us have at one time or another!
Dick T
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