Thermosyphon warming process

[Andy Bennett]

Further to the earlier post which covered the question of the thermosyphon process, I have found the step by step pictures I took of the warming process. 
The heat patterns are relative rather than specific temperatures but here goes step by step with timings shown. I have to do in 2 posts as i appear to be limited on pictures per post:
Engine cold:

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Engine head warming but no sign of any heat going into radiator

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First sign of some heat travelling into radiator

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First sign of real heat into top of radiator by the inlet

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more heat into top of radiator but rad still cool

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heat beginning to travel down height of radiator less than 4 minutes after start up

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more to follow

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next picture
top of radiator temp stable but heat travelling down suggesting thermosyphoning running now

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30 seconds later more heat at the base of the radiator

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again a few seconds later with the engine hot but the radiator still not at full working temp and still relatively cool at bottom

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30 seconds after last radiator picture and the heat pattern is relatively stable and remained like this with the radiator core middle at 86 degrees

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engine now at even temperature, just over 5 minutes from start up

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All of course at a standstill so not real driving, but temperatures appeared to stabelize at the 5 minutes or so point from start up at a relatively low 17 degrees ambient.

[Graham Barker]

Hi Andy, that's a very useful observation. I am looking forward to seeing the final set of photos. 
Cheers 
Graham

[Andy Bennett]

That's the full set now Graham. It appeared to tag on the second message to the first

[Nick Salmon]

Very interesting indeed. Thanks for taking the time to compile the images.

[Andy Bennett]

No problem, I found the efficiency of the carburettor remaining stone cold on the last picture whilst all about it is hot is impressive.

[Tony Griffiths]

Super pictures, thank you for posting them Andy. Most interesting to see the very cold carburettor. As my flight instructor once said, "Inside a carburettor, it's always winter." i.e. the evaporation of the fuel causes a significant drop in temperature and, in an extreme case, inlet manifold icing. On one of my cars. a '29 fitted with a side-draught SU suffers from this. The cure is a hot-spot, created by the application of several turns of wire wrapped around the exhaust pipe and inlet manifold.
On a piston-engined light aircraft, when it flies into a different flavour of air and suffers from ice-accumulated misfiring, there's a lever to select "Hot Air". The ice then melts, the engine misfire worsens, the pilot panics thinking he's made it worse, switches off hot air - and the engine stops.

[Colin Morgan]

Interesting that heat appears to build up initially at the top of the radiator before the flow becomes properly established? (Pictures 4 and 6). It is this effect that perhaps helps with a quicker warm-up compared with an unthermostated pumped system?

[AustinWood]

The best solution is a Renault thermostat inside the top hose. The engine then warms up before the thermostat opens. It also runs at a more sensible temperature.
If used in winter with thermo-syphon the engine is over-cooled and doesn't reach a good operating temperature.

[Bob Culver]

Considering the enthusiam for expensive oils, I am surprised not more interest in thermostats which according to the books likely reduce wear far more  than any difference of post 1940s oils.

[Ian Williams]

I think that is the exhaust in those pictures Colin, what I am curious about is why the horn was so hot at start up??