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Rollmop
Joined: 23 Dec 2016 Posts: 14 Location: Market Drayton, Shropshire
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Posted: Tue Aug 11, 2020 7:24 am Post subject: |
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Thanks for all of your constructive replies. I could be a little cautious on the engine heat but, being a non pressurised system, the boiling point is going to be 100C and a contact thermometer has given 93C temperatures on the actual head. I have changed to Prestone coolant because they give a boiling point on their fluid of 129C. The gauge has recently been refurbished so I don’t think that is inaccurate. Perhaps I worry too much. Thanks again _________________ Failure is not an option - in my case it is usually a feature.
1971 Herald convertible
1952 Triumph Mayflower |
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Rollmop
Joined: 23 Dec 2016 Posts: 14 Location: Market Drayton, Shropshire
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Posted: Tue Aug 11, 2020 7:24 am Post subject: |
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Thanks for all of your constructive replies. I could be a little cautious on the engine heat but, being a non pressurised system, the boiling point is going to be 100C and a contact thermometer has given 93C temperatures on the actual head. I have changed to Prestone coolant because they give a boiling point on their fluid of 129C. The gauge has recently been refurbished so I don’t think that is inaccurate. Perhaps I worry too much. Thanks again _________________ Failure is not an option - in my case it is usually a feature.
1971 Herald convertible
1952 Triumph Mayflower |
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alastairq
Joined: 14 Oct 2016 Posts: 1953 Location: East Yorkshire
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Posted: Tue Aug 11, 2020 7:32 am Post subject: |
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Rollmop wrote: | Thanks for all of your constructive replies. I could be a little cautious on the engine heat but, being a non pressurised system, the boiling point is going to be 100C and a contact thermometer has given 93C temperatures on the actual head. I have changed to Prestone coolant because they give a boiling point on their fluid of 129C. The gauge has recently been refurbished so I don’t think that is inaccurate. Perhaps I worry too much. Thanks again |
Can I draw your attention to the article in the Mayflower club' website?
The one about issues with the thermostat?
http://www.triumphmayflowerclub.com/documents/flowerpowers/articles/ _________________ Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces. |
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peter scott
Joined: 18 Dec 2007 Posts: 7118 Location: Edinburgh
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Posted: Tue Aug 11, 2020 9:18 am Post subject: |
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When the thermostat opens it is also supposed to shut off the bypass hose. If the bypass is not shut off then much of your water circulation will not be passing through the radiator. You might be able to test this if you can shut off the bypass hose by clamping it.
Peter _________________ http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon |
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Ray White
Joined: 02 Dec 2014 Posts: 6312 Location: Derby
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Posted: Tue Aug 11, 2020 10:37 am Post subject: |
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peter scott wrote: | When the thermostat opens it is also supposed to shut off the bypass hose. If the bypass is not shut off then much of your water circulation will not be passing through the radiator. You might be able to test this if you can shut off the bypass hose by clamping it.
Peter |
I have discovered that this is also a problem with XPAG engines where the original, rather sophisticated, thermostat is no longer available; or if it is, then it will be a reproduction that fails to close the bypass properly.
The answer that has been proven to work reasonably well, is fitting a common wax stat thermostat and adding a restrictor plate to the bypass opening. The small opening also acts as a breather. |
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badhuis
Joined: 20 Aug 2008 Posts: 1390 Location: Netherlands
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Posted: Tue Aug 11, 2020 1:43 pm Post subject: |
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The same problem also appears with the Triumph TR 4 cylinder engine. After replacing the "modern" type of thermostat with an old type bellows, the engine ran cooler. _________________ a car stops being fun when it becomes an investment |
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Ray White
Joined: 02 Dec 2014 Posts: 6312 Location: Derby
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Posted: Tue Aug 11, 2020 2:48 pm Post subject: |
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badhuis wrote: | The same problem also appears with the Triumph TR 4 cylinder engine. After replacing the "modern" type of thermostat with an old type bellows, the engine ran cooler. |
Not wishing to hijack this thread ... but I wonder if the Land Rover thermostat (as above) will work in the XPAG. Only reason is the original design sells for nearly £100. ! |
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alanb
Joined: 10 Sep 2012 Posts: 516 Location: Berkshire.
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Posted: Tue Aug 11, 2020 3:52 pm Post subject: |
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If it has a water pump and thermostat then surely it is a pressurised system? The cylinder head will be considerably hotter than the water the best place to check the temperature is at the top hose or radiator header tank. _________________ old tourer
Morris 8 two seater |
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Ray White
Joined: 02 Dec 2014 Posts: 6312 Location: Derby
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Posted: Tue Aug 11, 2020 4:27 pm Post subject: |
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alanb wrote: | If it has a water pump and thermostat then surely it is a pressurised system? The cylinder head will be considerably hotter than the water the best place to check the temperature is at the top hose or radiator header tank. |
I agree with that.
Also, non pressurised systems rely entirely on thermo syphon and likely will have a taller radiator probably with a Boyce or Calormeter mounted on the top.
Once pressurised systems could be thermostatically controlled, manufacturers became so confident that they often did away with the water temperature gauge. |
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alanb
Joined: 10 Sep 2012 Posts: 516 Location: Berkshire.
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Posted: Tue Aug 11, 2020 4:44 pm Post subject: |
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My Morris 8 is thermo syphon and has a very tall radiator compared to a modern pressurised one, on the cars I’ve had with a temp gauge Normal has been around 80c _________________ old tourer
Morris 8 two seater |
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Rollmop
Joined: 23 Dec 2016 Posts: 14 Location: Market Drayton, Shropshire
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Posted: Fri Aug 14, 2020 10:37 am Post subject: |
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The Mayflower is a bit of an oddball regarding the cooling water, yes it has a water pump so it is not thermosyphon but it does not have a pressurised radiator and has a free to atmosphere overflow. Regarding the thermostat, I managed to pick up an NOS early Landrover thermostat which has the bypass cover, I will however try the clamp on the bypass hose. _________________ Failure is not an option - in my case it is usually a feature.
1971 Herald convertible
1952 Triumph Mayflower |
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alastairq
Joined: 14 Oct 2016 Posts: 1953 Location: East Yorkshire
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Posted: Fri Aug 14, 2020 10:53 am Post subject: |
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Quote: | but it does not have a pressurised radiator and has a free to atmosphere overflow |
What kind of filler cap does it have? _________________ Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces. |
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lowdrag
Joined: 10 Apr 2009 Posts: 1585 Location: Le Mans
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Posted: Fri Aug 14, 2020 11:33 am Post subject: |
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My ears pricked up when I saw wax stats mentioned. I had a few for the Jaguar but they are all gone now and the new stats fail closed as opposed to open, which worries me a bit. So, are wax stats still available? The Jaguar ones are found in Zephyrs and many cars so not make or model specific. |
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Keith D
Joined: 16 Oct 2008 Posts: 1129 Location: Upper Swan, Western Australia
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Posted: Fri Aug 14, 2020 12:31 pm Post subject: |
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Rollmop,
Many cars of the same vintage as your Mayflower had exactly the same arrangement. All the Austin range had water pumps, thermostats with un-pressurised cooling systems.
Keith _________________ 1926 Chrysler 60 tourer
1932 Austin Seven RN long wheelbase box sedan
1950 Austin A40 tourer
1999 BMW Z3
Its weird being the same age as old people.
You are either part of the problem or part of the solution |
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Penman
Joined: 23 Nov 2007 Posts: 4756 Location: Swindon, Wilts.
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Posted: Fri Aug 14, 2020 1:53 pm Post subject: |
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Hi
With a vent to air system like that a bottle at the bottom of the vent tube can capture the "lost" coolant and it might even suck it back into the rad when the engine cools down if the vent tube reaches the bottom of the bottle.
Even if it doesn't suck it back at least you have saved that coolant to put back in the rad and reduce the need to keep topping up with fresh coolant. _________________ Bristols should always come in pairs.
Any 2 from:-
Straight 6
V8 V10 |
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