Regarding thermostat bypass topic: a TR4 aficionado named John H. (see quote
below) has looked at quite a few TR waterpump 'bodies' (the manifold part, not
the section with the impeller) and discovered that some of the bypass 'input
openings' (where the bypass hose hooks into manifold) had been REDUCED AT THE
FACTORY (the 'mold' was altered BEFORE casting).
The typical TR2-3-4 opening is 9/16" and he found a few manifolds that had
been reduced by almost half to 5/16" - in the cast.
Perhaps this modified waterpump body (or manifold) is the reason late TR4s
and TR4As were shipped without sleeved thermostats from the factory..
'be interesting if someone could find an alternative part # in the TR4-A
Parts Catalogue. My TR4 Part Catalogue only shows one item under WATER PUMP
ASSEMBLY - Body, water pump: # 57014. Any alternate numbers out there?
If the factory reduced the hole from 9/16" to 5/16" eliminating the need for
the sleeved thermostat, then inserting a washer with a 5/16" hole in the
bypass hose seems the way to go.
Carl
'63 TR4 since '74
"I checked the By-pass outlet on some of my extra (waterpump) housings. They
are 21/64 (about 5/16"). You can see where they modified the pattern to make
a smaller
opening. John H. - Petaluma CA"
>>..There is evidence that even the factory came around to this view
eventually ... late TR4s were delivered with non-sleeved thermostats and the
bypass
open.. Randall<<
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