replacement valves seem to have a different slope on the slot that controls
the position of the valve inner parts. The slope makes it take more effort
to get past the point where the valve closes, so the cable can't push hard
enough. A couple years ago someone on the list compared an original valve
and a replacement that had this issue. It is probably possible to change the
profile to make it easier to close, but then it may also open easier by
Ann Arbor, MI USA
Too many Hobbies.... Too Little Time
1969 Lotus Elan....It's not a restoration, it's a never-ending adventure.
Lotus folks -
If the heater valve is difficult to operate, then it is
either the cable or (more likely) the unit itself. In order
to fit my heater valve back on the engine (after putting on
the new body) without raising the engine, I took mine apart.
It took about 5 minutes to get apart and 20 minutes total to
fix. When I did so, I found a bit of crud in the valve - so
after several years I could imagine that there would be
enough to keep it from closing properly. As you pull back on
the cable - the angled slot in the outer housing makes the
valve body go in and out. A very very simple mechanism, but
what's happening is that the valve itself is catching on
stuff on the inside. No amount of oiling on the outside will
ever fix it.
To fix it - Disconnect the control cable. Then, just drill
out the 1/8 "
Aluminum pop rivit that holds the inner and outer part of the
Then rotate the housing 1/12 turn and the flanges will no
longer be underneath their u-shaped keepers. Bingo - you can
now remove the outer heater valve housing and the valve
itself. The part of the heater valve housing that is in the
upper part of the head is still there. Clean out the crud -
and you're ready to reassemble. You will loose some
antifreeze as you disassemble the valve body - so put a can
under the setup.
Enjoy - an easy job. As easy as fitting an in-line valve
while retaining original mechanisms Paul Zimmerman
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