Supercharged

[halg]

One of the issues that must be addressed in any engine that is to have forced induction added is the cooling system. I could not believe that Fiat would design the water pump in the early(1438 & 1608) to be deadheaded(no bypass) Mark mentioned this in a post about someone wanting to go back to the internal thermostat. In roding out the block and head(to make sure everything was clear) I found out there is a bypass. I can't say for sure, in any engine but mine, the water passage at the front of the head, only goes to a hole under the thermostat then down the block and out the front to the suction side of the water pump. This would allow water to circulate with the thermostat closed(be it a small amount) With the thermostat open this passage would probably not flow anything. If this is true then any head should be able to be put on any block, by closing off this passage at both ends. An external thermostat would have to be used. I don't know all of the different cars Fiat put these engines in but if, like Spiders, all late engines had the external thermostats it seems strange that they continued putting this bybass system in all the engines. PBS, in some of their engine information, indicates the front water passage is the only issue in putting any head on any block. I don't have all the combinations to say this is true or not.
The cooling issue associated with my supercharger will hopefully be handled by using a 2.0L water pump(25% larger impeller) in my 1608. this water pump has a cavity that encompasses where either outlet comes out the front of the block. The water pump gaskets I have, has both holes. I haven't decided about the radiator yet.
Hal

[htchevyii]

Sounds like a neat project, keep us informed in the progress.

[So Cal Mark]

an internal bypass would make sense, I couldn't imagine how the system would work very well without a bypass. I hadn't taken the time to trace the water passages