+- Austinsevenfriends (https://www.austinsevenfriends.co.uk/forum)
+-- Forum: Austin Seven Friends Forum (https://www.austinsevenfriends.co.uk/forum/forumdisplay.php?fid=1)
+--- Forum: Forum chat... (https://www.austinsevenfriends.co.uk/forum/forumdisplay.php?fid=14)
+--- Thread: Thermosyphon warming process (/showthread.php?tid=7497)
Thermosyphon warming process - Andy Bennett - 11-05-2022
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:
1.jpg (Size: 128.47 KB / Downloads: 778)
Engine head warming but no sign of any heat going into radiator
2.jpg (Size: 101.5 KB / Downloads: 777)
First sign of some heat travelling into radiator
3.jpg (Size: 107.74 KB / Downloads: 781)
First sign of real heat into top of radiator by the inlet
4.jpg (Size: 129.34 KB / Downloads: 778)
more heat into top of radiator but rad still cool
5.jpg (Size: 110.87 KB / Downloads: 778)
heat beginning to travel down height of radiator less than 4 minutes after start up
6.jpg (Size: 123.68 KB / Downloads: 783)
more to follow
next picture
top of radiator temp stable but heat travelling down suggesting thermosyphoning running now
7.jpg (Size: 125.05 KB / Downloads: 774)
30 seconds later more heat at the base of the radiator
8.jpg (Size: 125.01 KB / Downloads: 777)
again a few seconds later with the engine hot but the radiator still not at full working temp and still relatively cool at bottom
9.jpg (Size: 109.98 KB / Downloads: 777)
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
10.jpg (Size: 121.86 KB / Downloads: 780)
engine now at even temperature, just over 5 minutes from start up
11.jpg (Size: 108.06 KB / Downloads: 785)
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.
RE: Thermosyphon warming process - Graham Barker - 11-05-2022
Hi Andy, that's a very useful observation. I am looking forward to seeing the final set of photos.
Cheers
Graham
RE: Thermosyphon warming process - Andy Bennett - 12-05-2022
That's the full set now Graham. It appeared to tag on the second message to the first
RE: Thermosyphon warming process - Nick Salmon - 12-05-2022
Very interesting indeed. Thanks for taking the time to compile the images.
RE: Thermosyphon warming process - Andy Bennett - 12-05-2022
No problem, I found the efficiency of the carburettor remaining stone cold on the last picture whilst all about it is hot is impressive.
RE: Thermosyphon warming process - Tony Griffiths - 12-05-2022
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.
RE: Thermosyphon warming process - Colin Morgan - 12-05-2022
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?
RE: Thermosyphon warming process - AustinWood - 12-05-2022
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.
RE: Thermosyphon warming process - Bob Culver - 12-05-2022
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.
RE: Thermosyphon warming process - Ian Williams - 12-05-2022
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??