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There is a good section on the 'what have you done...' on retrofitting a thermostat in the top hose. A couple of people have mentioned things getting too hot with it on and thus taken off the mod. Fine in winter etc.
I just wondered if it might be worth revisiting what people have used, what the actuating temperature was, and if everyone has been ticketyboo/any observations in hindsight etc.
It's a bit difficult to link to it in a huge thread hence this one.
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Location: Auckland, NZ
29-04-2021, 12:01 AM
(This post was last modified: 29-04-2021, 12:04 AM by Bob Culver.)
It is important there is some bypass such as a hole in the thermostat or weird effects can occur. Textbooks claim a major reduction in cyl and ring wear. Reduces crankcase condensation , major cause of deterioration of roller bearings.
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OK, so real world experience from participating Seven owners? Who has had fuel vapourisation occurences etc.? or has its addition been forgotten about?
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Location: Scottish Borders
I fitted the thermostat in February 2015. Since then we have covered 10,540 miles with no problems whatsoever. The car boiled only twice. Once climbing a notorious hill in The Dales on one of Malcolm Parker's runs and once in Perth on the way to Blair Atholl for the SA7C's AGM in November 2017. We were in a traffic jam for 20mins with no fan belt. I remove it in the winter.
I had to replace the thermostat recently because the original one failed.
The car has a motormeter so we can see what's going on. The engine warms up quickly then maintains a steady temperature. I drilled two 1/8" holes through the flange to allow bypass and make sure they are placed vertically to avoid air-locks. However with no water pump there should be virtually no pressure across the thermostat unless the engine boils so normally bypass is not needed.
The flow rate of thermo-syphon is probably very low so the thermostat should make no difference.
We have only had fuel vapourisation once. It was on the way to Malcolm's Masham to Kelso run. We climbed to the top of one of the highest roads in England in very hot weather and stopped to admire the view. The car was reluctant to restart and the carburetor was boiling merrily. It did start and ran very rough for a few minutes. It is an updraught Zenith.
I can't see how a thermostat could affect vapourisation.
Jim
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any ideas on what the engine coolant temp IS on a standard engine without the mod, anyone? The Renault inlines are generally 86 or 88 degrees C.
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My 1935 Ruby with a new core and a digital temperature gauge in the top tank runs at 83 Degrees C on a 24 Degree day in Australia.
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We have now way of measuring cylinder block temperature. My guess is that with no thermostat it is similar to the top tank. With thermostat it will be in about the same range as the thermostat setting, low 80s.
On a winters day in UK, say -4C, with no thermostat I would guess the engine gets nowhere near 80C.
Jim
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So Jim, is yours defiinitely a low 80s thermostat? They do go down as far as 75 (low coolant version on a GT Turbo) but generally they are a lot more money!
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Yes I think so. In the scheme of things it won't matter but I would think 75C would be too low. Engines are best if running above 80C.
Jim
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JonE, the one which I have purchased but not yet got around to fitting opens at 86 degrees C.
