Hi Rob,
Not sure if this is useful, but I purchased a 'New Old Stock' thermostat from eBay recently, hoping it would fit. It turns out to be the older 'bellows' type and is exactly the same dimensions and operating temperature as the usual Jowett Javelin ones, so it looks good! The operating temperature is 77 degrees.
To make it exactly identical, I will need to drill the two small holes in the opening top 'lid', as Jowett's recommended. The part I have purchased is probably from an early 'Series' Landrover and is in a Rover box. The Rover part number is 515962.
You can probably still get them from Landrover specialists.
I am not sure if you could use a modern waxstat thermostat, as these might have different operating characteristics.
Hope this is useful.
All the best,
David
Thermostat
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David Morris
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David Morris
- Posts: 837
- Joined: Thu Feb 09, 2006 9:23 am
- Your interest in the forum: Jowett Javelins since 1964. Now a Jowett Stationary engine owner and club member since 1964.
- Given Name: David
- Location: Sunny Bristol
Thermostat
Hi Rob,
It looks as if your car has had part of the late modification to the water system carried out, but not completed.
I have copied the section from the Javelin Handbook for you below :-
APPENDIX I
Modification to the Water Circulation
This modification was to have been introduced on Javelins just prior to the close of the factory and it is strongly recommended that this should be fitted if possible.
The engine as originally produced often did not transmit enough heat to the thermostat to operate it. This resulted in water circulating back up the radiator causing local overheating and bad running on. To offset this two large bleed holes were made in the thermostat to increase flow. This very much reduced the value of the thermostat and thus the engine tends to warm up very slowly.
A by-product of this later modification is faster warm up, which eliminates overheating, and a heater which will give heat very quickly. No extra heat can be expected once the engine is up to normal running temperature.
Note that the dimensions specified must be adhered to and as this circuit was a result of considerable research, modifications are likely to impair its efficiency.
On to each of the water inlet pipes on the rear of the crankcases braze a ½â€
It looks as if your car has had part of the late modification to the water system carried out, but not completed.
I have copied the section from the Javelin Handbook for you below :-
APPENDIX I
Modification to the Water Circulation
This modification was to have been introduced on Javelins just prior to the close of the factory and it is strongly recommended that this should be fitted if possible.
The engine as originally produced often did not transmit enough heat to the thermostat to operate it. This resulted in water circulating back up the radiator causing local overheating and bad running on. To offset this two large bleed holes were made in the thermostat to increase flow. This very much reduced the value of the thermostat and thus the engine tends to warm up very slowly.
A by-product of this later modification is faster warm up, which eliminates overheating, and a heater which will give heat very quickly. No extra heat can be expected once the engine is up to normal running temperature.
Note that the dimensions specified must be adhered to and as this circuit was a result of considerable research, modifications are likely to impair its efficiency.
On to each of the water inlet pipes on the rear of the crankcases braze a ½â€
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Keith Clements
- websitedesign
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- Your interest in the forum: Jup NKD 258, the most widely travelled , raced and rallied Jowett.
- Given Name: Keith
- Contact:
Would it be possible to make a batch of the timing cover bypass part for sale?
Ideally a batch of modified covers would be useful as I would not be happy taking the cover to a local welder to ruin. Finding one to do it at a reasonable price is not easy. We could do it on an exchange basis or send a batch off for processing.
Personally I could offer about five covers for modification. The only worry is the usual Jowett one of differences in timing covers.
While we are about it, you may like to look at the late Ben Shaw's mod for replacing the rubber connector between water pump and cover. I provided Jim Miller with the patterns and he was going to have some flanges cast. http://jowett.org/jowettnet/dt/tech/mods/mods.htm
Ideally a batch of modified covers would be useful as I would not be happy taking the cover to a local welder to ruin. Finding one to do it at a reasonable price is not easy. We could do it on an exchange basis or send a batch off for processing.
Personally I could offer about five covers for modification. The only worry is the usual Jowett one of differences in timing covers.
While we are about it, you may like to look at the late Ben Shaw's mod for replacing the rubber connector between water pump and cover. I provided Jim Miller with the patterns and he was going to have some flanges cast. http://jowett.org/jowettnet/dt/tech/mods/mods.htm
skype = keithaclements ;