18-10-2019, 09:22 PM
(This post was last modified: 20-10-2019, 08:32 AM by Colin Morgan.)
It says in the Vintage Alvis Manual (14.9) that the water capacity in a thermosyphon system was designed to provide a buffer against overheating (not necessarily boiling, but higher than desirable oil temperatures), which makes sense given the variable power requirements on the engine in normal driving before motorways. The above calculation is intended to show that the quantity of water between low and high levels in the top tank, which turns out to be small, has little effect on this ability to ride out these variations - so trying to keep the top tank topped up for this purpose is pointless.
At the moment, I am adjusting from running a slightly leaky, heavily clogged radiator for many years. It was from late 1938 and had a pressure relief valve fitted. The older type replacement does not leak and runs at about 80 degrees instead of 90+. However, after noticing it was losing water by 'slosh', I wondered if this was usual. If I could keep the level a bit higher I would, but from what is being said, this is not necessary - or even possible. So, it seems the extra headroom in the top tank was provided to cope with the losses by 'slosh' - surprised Austin would accept the extra radiator height and brass just for this. Thank you for all the replies. Half a litre of water to cross half of Europe and back is impressive.
Colin
At the moment, I am adjusting from running a slightly leaky, heavily clogged radiator for many years. It was from late 1938 and had a pressure relief valve fitted. The older type replacement does not leak and runs at about 80 degrees instead of 90+. However, after noticing it was losing water by 'slosh', I wondered if this was usual. If I could keep the level a bit higher I would, but from what is being said, this is not necessary - or even possible. So, it seems the extra headroom in the top tank was provided to cope with the losses by 'slosh' - surprised Austin would accept the extra radiator height and brass just for this. Thank you for all the replies. Half a litre of water to cross half of Europe and back is impressive.
Colin