Kit car - cooling fans
Discussion
rushdriver said:
If it's got a thermo stat then turn it right down so it will kick in when th temp is relatively low, apart from that take it for a spank, pull over and let the engine idle and see if it kicks in
John
How can I check for one of them?
Sorry, new to the kit car malarky as I've just purchased a Cobra from Hallmark.
Mobster Raks said:
If it's got a thermo stat then turn it right down so it will kick in when th temp is relatively low, apart from that take it for a spank, pull over and let the engine idle and see if it kicks in
John
How can I check for one of them?
Sorry, new to the kit car malarky as I've just purchased a Cobra from Hallmark.
If it's a Kenlow for example there will be a thermostat somewhere, however it may be worth just taking it for a run and letting it idle, keeping a keen eye on the temp guage though
John
you can see the thermostat control for mine Kenlowe Unit on the far right of this picture:
It's the round central heating styled knob with red label on top.
You could test it as suggested, note it's current location and turn down to minimum and check it switches on, but personally I'd be inclinded to let the engine run and then idle watching temperatures and making sure the fan kicks in roughly halfway up your temperature scale.
It's the round central heating styled knob with red label on top.
You could test it as suggested, note it's current location and turn down to minimum and check it switches on, but personally I'd be inclinded to let the engine run and then idle watching temperatures and making sure the fan kicks in roughly halfway up your temperature scale.
Mobster Raks said:
you know, when you guys said thermostat control, i didn't think you actually meant a thermostat control!!!
There is a pretty good electronic version for about £50, the thermostat comes built into an ali tube so you just cut the top hose and remove about an inch of it and fix the tube in its place. Comes with a 40A relay so only needs an earth and a fused feed from the battery. Can be adjusted to turn the fan on between 72 and 120 degrees. Got one on my Dax and it works well without the need to insert a tube into the water pipe which can often leak.
Get them from Demon Thieves, Merlin Motorsport, Ralley Design (cheapest) etc The pipes are available in various sizes to suit almost any cooling system.
I been researching rads and fans issues recently for my kit, and found out the following useful stuff related to overheating problems and cures:
simply having a rad and fan isn't necessarily enough. The rad might not transfer out enough heat, and the fan may not move enough air. Obviously, in hot weather, these problems could move from "concerns about running a bit hot" to "engine overheating".
Possible remedies to too much heat:
1. Check existing cooling system is working correctly. Check rad, fan, hoses and water circuit. There may be a blockage in the pipes, the pump may be going, etc.
2. Removing the water thermostat is not a solution, except as a temporary measure if it is stuck. In fact, removing the thermostat can cause overheating, as the flow at that point in the circuit is now greater, and the pressure before it is now lower. The thermostat creates a constraint to the water flow, even when fully open, and the engine is designed to run with that constraint. If the engine is overheating, and the thermostat is working, then removing it will at best merely delay the overheat a little, and at worse make the overheating problem even worse by incorrect flow and pressures inside the water circuit.
3. Bigger rad: the obvious one, but possibly the least feasible. You probably already have pretty much the tallest/widest rad. Even if there is enough space, you may find that there is no airflow through the new areas of rad real estate.
4. Ally rad: I'm told that ally rads transfer the heat from the water more efficiently than brass, and so improve cooling, for a given size and thickness. They are, however, more expensive.
5. Thicker rad: you might replace your rad with a thicker one from a specialist fabricator, providing more radiating surface area to shed the heat from the water. I believe 3 core is about the most normally, though it is possible to go to more. The problem with thicker rads is that it is more difficult for the air to pass through the rad, which reduces the cooling effect. In the worst case, you can get a "wall" of hot air building up on the leading side of the rad.
6. More powerful fan: if the fan is incapable of moving enough fresh air through the rad fins, then the radiated heat is not taken away from the rad. The thicker the rad, the more powerful the fan required. Not all fans of the same size are equal - look at CFM. A good 12" fan may move lots of air, but cost 80 quid or more, whereas you could get a 12" fan from the breakers for a couple of quid, but it probably won't move the necessary amount of air.
Putting all that waffle together, I'd recommend by all means check your thermostatic fans are switch on early enough. However, if your cooling is fundamentally inadequate, starting the fan at a lower temp will only delay the moment of overheat a little. Also check over the whole cooling system.
All IMHO in the spirit of spreading knowledge I've picked up recently, Pum.
simply having a rad and fan isn't necessarily enough. The rad might not transfer out enough heat, and the fan may not move enough air. Obviously, in hot weather, these problems could move from "concerns about running a bit hot" to "engine overheating".
Possible remedies to too much heat:
1. Check existing cooling system is working correctly. Check rad, fan, hoses and water circuit. There may be a blockage in the pipes, the pump may be going, etc.
2. Removing the water thermostat is not a solution, except as a temporary measure if it is stuck. In fact, removing the thermostat can cause overheating, as the flow at that point in the circuit is now greater, and the pressure before it is now lower. The thermostat creates a constraint to the water flow, even when fully open, and the engine is designed to run with that constraint. If the engine is overheating, and the thermostat is working, then removing it will at best merely delay the overheat a little, and at worse make the overheating problem even worse by incorrect flow and pressures inside the water circuit.
3. Bigger rad: the obvious one, but possibly the least feasible. You probably already have pretty much the tallest/widest rad. Even if there is enough space, you may find that there is no airflow through the new areas of rad real estate.
4. Ally rad: I'm told that ally rads transfer the heat from the water more efficiently than brass, and so improve cooling, for a given size and thickness. They are, however, more expensive.
5. Thicker rad: you might replace your rad with a thicker one from a specialist fabricator, providing more radiating surface area to shed the heat from the water. I believe 3 core is about the most normally, though it is possible to go to more. The problem with thicker rads is that it is more difficult for the air to pass through the rad, which reduces the cooling effect. In the worst case, you can get a "wall" of hot air building up on the leading side of the rad.
6. More powerful fan: if the fan is incapable of moving enough fresh air through the rad fins, then the radiated heat is not taken away from the rad. The thicker the rad, the more powerful the fan required. Not all fans of the same size are equal - look at CFM. A good 12" fan may move lots of air, but cost 80 quid or more, whereas you could get a 12" fan from the breakers for a couple of quid, but it probably won't move the necessary amount of air.
Putting all that waffle together, I'd recommend by all means check your thermostatic fans are switch on early enough. However, if your cooling is fundamentally inadequate, starting the fan at a lower temp will only delay the moment of overheat a little. Also check over the whole cooling system.
All IMHO in the spirit of spreading knowledge I've picked up recently, Pum.
I agree with all that Pum has said, you need to make the air go through the radiator, not just "at it" so unless the fan sits up against the rad, you'll need to cowl it in. We have "7" type cars, these were notorious for overheating, but with a decent fan & rad combination they aren't a problem any more.
http://nw.rhocar.org/radiators.htm (see here)
I would suggest this way of wiring up the thermostatic switch
http://nw.rhocar.org/fan%20wiring.htm
Jim
http://nw.rhocar.org/radiators.htm (see here)
I would suggest this way of wiring up the thermostatic switch
http://nw.rhocar.org/fan%20wiring.htm
Jim
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