During the winter it runs at 180 which corresponds to the thermostat. In the summer when temperatures get into the upper 90’s and above, which happens nearly all summer in central California it gets up to near 220 and stays there whether I am in stop and go traffic or driving on the freeway. A 160 degree thermostat has not brought about improvement. I have tried a heavy duty thermal fan clutch without resolution. Initial timing is 9 degrees BTDC. Final timing I believe is 30 + 12 vacuum advance if recollection serves me correctly but I have moved it up and down with no improvement. The radiator is a quality 4 core radiator which is about as good as you can get without going to an aluminum one. Although aluminum would be better I believe the copper brass unit should be fine if all else is correct at least it has worked for many others.
I would expect a reduction in pinging going from 10.5:1 down to 9.0:1 and using a cam that has the intake closing event a full 5 degrees later. An ideal quench distance is, from what I have read, about 0.039. The 8 valve relief cast pistons puts me at the original of 0.015 + gasket thickness of 0.039 which equals 0.054 + the additional 0.020 lower piston top which puts me at 0.074 Which is a full 0.035 higher then optimal actually nearly twice the recommended distance. From what I have read the factory piston pin to piston top is 1.72 while the cast piston is 1.70. Doesn’t this make a big difference in heat generation within the combustion chamber? What are the downsides to the thinner gasket?
Mark
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