M42 Cooling System questions

[gusgriff]

I see a number of posts about cooling issues on the M42 and M44 engines. I need to separate fact from fiction. I have talked to a couple local people that said the M42 has a tendency to overheat. Another person said the engine cooling jacket design is less than optimum and opined that the M44 attempted to correct the faults. I have seem a number of posts on suggestions, mods and tips.

What is the real facts the M42 and M44 cooling system? what is the best maintenance steps and what mods, if any, give the most bang for the buck. I not believe throwing money after a problem is always the best solution.

An example is the $200-$300 Hi-Cap water pump. This is 4-6 times more than the stock pump. How much does it really increase GPM throughput. It may be worth it but the cooling jacket pressure drop increases with flow throughput. This pressure drop is close to being exponential I doubt it moves that much more water through the system. If the manufacturer says it moves twice as much they are quiet generous and if they say more you need to look at their test equipment.

The next hurtle is with increased flow is the radiator which is the same as with the engine cooling jacket. The pressure drop through the tubes/channels is added to the cooling jacking pressure drop. Bigger channels help the flow but not always the issue of heat transfer. You need as many heated water molecules as possible in contact with the channel metal/fins. I do not know now efficient the stock radiator is but if near max heat exchange with the stock water pump the Hi-Cap pump is not getting the help it needs to do the job. You need either more surface area of more airflow. If I am wrong please left me know.