Thermostat Housing

[rgh0]

Maybe Ford in their manual copied what they used for the iron head Escorts ? who knows?

The thermostat is a a simple proportional controller ( if you dont know what that is I can explain it) it starts to open at its rated temeprature and opens further as the temperature increases. The actual operating temperature depends on many variables including radiator size and air flow rate. The Escort had a larger radiator and multi bladed plastic fan so a High temp thermostat maybe give a similar operating temperature to a lower one in an Elan. I dont know all the variables but I can easily understand the directional influences. But if you want a post grad degree level class in heat transfer I am willing to give it to anyone who wants to learn.

cheers
Rohan

I may know a little about Twinscams but I know a f**ing lot about heat transfer

[512BB]

'What year was that workshop manual you are reading from Leslie published?'

1971 and included specs for the Big Valve engine.

[berni29]

Hi

Not wishing to get into specifics or right wrongs, is it correct to say that the thermostat (once it has opened) regulates the minimum temperature that the engine will run at, and the fan thermostat (or cooling system capacity for cooling) will regulate the maximum. So to get an engine to run at 85deg vs 90deg (for example) would require a fan cut in at 85deg rather than 90deg. Assuming that the fan actually does have the capacity to bring the temp down to the required level.

It seems to make sense that the cooling system should be able to being the engine down to the same temperature as the opening temperature of the thermostat if required.

All the best

Berni

[2cams70]

But if you want a post grad degree level class in heat transfer I am willing to give it to anyone who wants to learn.

I'm not smart enough to understand all that Rohan. Only the simple things I can understand - food, drink and that other one that starts with "S"

What year was that workshop manual you are reading from Leslie published?'

1971 and included specs for the Big Valve engine.

Interesting Leslie. Looking at the Ford manuals they changed the thermostat rating at the time of Mk2 Cortina introduction to the higher rated one. Prior to that the rating was the same as the Lotus figure (i.e for Anglia and Mk1 Cortina). Seems either Lotus got the figure when the engine was originally developed and Ford changed the specification later and Lotus didn't pick up on the change, there's a mistake in the manual or there is a technical reason why the Ford application for the Lotus engine is different to the Lotus one. You may be correct that the Lotus application is different because there's probably less airflow around the engine with consequent implications on fuel vapourisation, poor hot starting, etc. In the case of Ford the Lotus and regular engines all have the same thermostat.

Further to Rohan's comment - it does appear that the thermostat "rating" as such is a somewhat of a vague figure. The specs quote a start of opening figure and a fully open figure. When you say you've installed a 78C thermostat I believe it means it starts to open at 78C - what the set point is that it regulates around who knows?? Presumably it's at a figure somewhere midway between the start of opening and end of opening figure??

[Sadbrewer]

Just to add...back in the day at least the wax operated thermostats weren't precision pieces of kit...we were in the motor trade and my old man possessed an accurate mercury high temp thermometer. He'd drop thermostats and temperature probes into a pan on a gas ring and bring them up to temp to double check the performance.. and they were often well out from what was expected...it seems like a lot of trouble to go for a cheap item, but I remember he did it on every Hillman Imp or badged clone that had temperature issues as they weren't an easy car to work on.