I have a 1957 261ci six with a 235 head, casting number 3836848 in my 1951
pick up. The block and head were machined, magnafluxed (twice, no cracks)
and rebuilt, mild cam, bored .030", valves, seats, etc., etc. Since
installation in the truck it has overheated. I put a pressure tester on the
cooling system, it will not hold pressure. There are bubbles in the radiator
(new, Harmon's) when the thermostat (new, 170°F) opens. The water pump is a
short shaft unit from Partick's. I've assembled the head gasket (both
Fel-Pro, & Victor) dry, really bad, and with Permatex, Copper
Spray-a-Gasket, and Hylomar (sp?), better with the sealant, but it still
overheats. I've used the 235 torque sequence and the 261 torque sequence per
a McCord spec guide I have, taking the head down in increments to 95 ft-lbs
final torque. Started the truck, let it warm up, shut it down, drained the
coolant and retorqued the gasket. The last time I replaced the head gasket,
it was fine, initially, took it for a 8 - 10 mile ride, no problems. The
truck sat for about a week and when I started it up, it was overheating,
again. Does anyone have any ideas why I'm having this overheating problem?
Thanks,
John Lazar
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
|