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Cooling System Modification


alanrichey

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Those of you who followed all the threads we have run concerning the 2B Superspec cooling system will be aware that it is a bit Heath-Robinson. Although we have found it actually works very well (in fact too well on occasions), it has a design fault that means it can take up to 20 mins to reach working temperature.

 

The reason for this is that the original feed to the Rover heater has been re-plumbed so it goes through a pipe on top of the engine and into the top of the radiator, thereby bypassing the thermostat. We don't know if it was intentionally designed like that (the 'official' explanation is to assist with filling the radiator) but when I actually blocked the pipe as an experiment the engine certainly warmed up very quickly (5 mins) but then ran extremely hot during the trip, so I think it might actually serve another circulation purpose.

 

AndyW and I have been bouncing ideas around and Andy is going to try for a full redesign of the system so it is more like a normal car. I was thinking more along the lines of adding a separate thermostat in that cooling line so it is blocked off until the engine warmed up and then open while at running temperature. A google search for a standalone or inline housing for a standard car thermostat didn't produce anything. So the next idea was to adapt a central heating radiator valve but then I realised that those thermostats are designed to be open when cold and close when the temperature is reached. Just the opposite of what I want.

 

Has anyone any bright ideas how I can arrange for a 15mm (roughly) pipe to be blocked when cold but then open around 80C ?

 

Al

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Guest mcramsay

I would locate the thermal switch in the main coolant flow and not on the pipe that you are blocking off and then opening at temperature, as it may take a while for the pipe to heat up due to having no flow through it, any cheap adjustable fan thermostat should be able to switch the solenoid valve like it would a cooling fan,

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  • 5 weeks later...
  • 1 month later...

Not yet, AndyW and I are thinking of an alternative solution first. As a reminder the problem is that the original Rover heater return feed goes to the top of the radiator, bypassing the thermostat, so the warm up takes a long time. Removing the feed isn't an option as the engine then runs very hot, so it seems that once the engine has reached working temperature, the circulation is needed. So I was going to fit a thermostatic switch in the feed pipe.

 

But before doing that we are going to try taking the feed and moving it to the lower rad pipe, which was how it was designed in the original Rover fit. That way it doesn't bypass the thermostat but still maintains the circulation. I am just awaiting one 95 deg pipe bend to complete the setup.

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  • 9 months later...

Just to update this post from last year, I modified the cooling system on my Superspec over the winter and it seems hugely improved.

 

I removed the pipe over the top of the engine that returns the heater feed back into the top of the radiator, and blanked off the top centre radiator spigot. We've never believed this was correctly plumbed by RH as it means the water pump only draws water from the bottom of the radiator so all the water in the radiator has to warm up, making the thermostat effectively redundant. I then removed the U hose that takes the radiator bottom hose into the water pump, and replaced it with two 90 deg elbows with an alloy tee joining them. Some 17mm heater hose was then used to join the end of the metal pipe from the heater feed (I don't actually have a heater fitted), back into the alloy tee.

 

So there's now a warm-up loop and a main radiator loop. When the engine is cold the water comes out the top closed thermostat pipe around the 'heater' hose and back into the water pump. When it's hot and the thermostat opens, the water gets diverted into the top hose and through the radiator as it should do.

 

The net result of all this is that the engine now warms up to 83deg C working temperature in about 5 mins before the thermostat starts to open, rather than the 12 to 20 mins it used to take. Good result!

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