[ QUOTE ]
I remember reading somewhere at one time that the heater valve on the 1275 should be left open to help prevent no. 4 cylinder overheating problems. Is this true?
[/ QUOTE ]
...much more so in racing applications than in street use. Giving that most racers remove the heater, we run a hose from the valve back to the radiator. I have not checked personally but have been told the rear of the head will be up to 20 degrees F cooler doing this.
I first came across this while racing 948's. Once I ran the hose and opened the valve, no more blown head gaskets. Well, no more blown in the vicinity of #4 cylinder anyway... /ubbthreads/images/graemlins/cool.gif
Now running a 1275 in one car and a 948 in the other. I consider this essential on the race cars and prudent on the street car.
Tim