johnw wrote:Would be good to fit some sensors and actually get some figures logged. Flow volume, water temperature, pump effort, block temperature, under bonnet temperature, etc.
Questions we could then answer:
Flow volume at different RPM
Does a coolant flush help a 40 year old system, which flush?
Water wetter and different coolants, any improvements?
Effect of a given fan setup on the system?
Aluminium vs Copper radiator, is Copper really similar performance when both are new?
Electric water pump, any good?
Different pump impeller choices,
And of course:
How much does a filter impair the system?
Small rechargeable bluetooth sensor modules using IR sensor beams could be cable tied to hoses, etc, during the monitoring phase.
Someone could then develop a closed loop system using additional electric water pump and fan, which minimises additional power usage. This system could be very unobtrusive. The car could be otherwise stock, but for a front mounted radiator fan, and the electric pump, either of which could assist only when the stock system was overburdened.
My FFs never really overheated. Perhaps it is the extra bonnet space? I used to reverse flush the radiators and block out as soon as I bought one, then use Rad Flush, before finally refilling. No idea if that helped or not, but I would do that as well as changing the fluids.
My experience with other makes of V8. Keeping them cool on the streets has never been an issue but it has been when on a race track.
Water wetter - I believe this works to some extent but the biggest improvement relates to ditching the ethylene glycol. In comparison to 100 water, a 50% water/ethylene glycol solution will reduce the heat capacity by approximately 20% and the thermal conductivity by around a third.
Fans - having a shroud makes an enormous difference. A twin electric fan with shroud works well too. I use this with a twin temperature switch located at the exit of the radiator. The low switch point turns the fans onto low and the high switch point puts them onto high.
Impeller - This can make a massive difference. A poor impeller will cause cavitation (low pressure locations where the water turns to steam). The small steam bubbles then make there way to the highest point in the engine which just happens to be the heads and pockets of steam build up. Steam doesn't transfer heat as well as water and thus you get hot spots occurring. The engine may also make some thumping noises as the steam escapes out the return hose. The impellers I have used in the past were from John Bennet in Melbourne. They had been tested with a perspex sheet on the rear so that any cavitation could be seen. Depending on how hard the engine revs the impeller requirements can also vary.
Filter - That's easy to check. When you have done a coolant change and you are working any trapped air out of the system all you have to do is rev the engine and you can see the water flowing through the radiator. The filter makes next to no difference as far as I can see.
Thermostat - Using a Robert Shaw thermostat and not a Dayco thermostat was of benefit.
Oil cooler - This made the biggest difference of all when it came to cooling at the race track. The oil cooler has its own thermostat.
