Discussion
It's funny, I've run a 1275 metro engine in a mini with a standard rad, I was told it wouldn't keep it cool, but it worked fine. Ok, it was a bone-stock 1275, I reverse flushed the crud out of the rad, and used tap water with the minimum amount of antifreeze.
I would say a guarded "it *should* be ok" providing the rad is clean inside, and all the gills are present and in good shape. The only real way to know is to try it and see. If she runs out, you need to change the rad. Simple.
Edited to add : Header tank ?? That was a mod from the past, although the '90 model minis on have a sort of overflow catch tank fitted to the side of the rad. This is supposed to collect any water overflowed from the rad, and when the cooling system cools down the water can be drawn back into the rad.
These days on my 1380 I run the minispares supercool 2 core rad, use de-mineralised water with WaterWetter and the minimum of antifreeze, it has a thermostat blanking sleeve and the auxilary electric fan wired to a manual switch. I never shut the heater tap, just close the flap inside the car. I've got a capiliary temperature gauge calibrated in deg F, most of the time the temperature hovers about 160-170 F, on the weekend going to Stanford Hall on the motorway it climbed to 190 F. On trackdays I've seen 210 F, but that's generally on the rundown lap and when exiting the circuit at low speed.
>> Edited by phil hill on Wednesday 30th June 08:30
I would say a guarded "it *should* be ok" providing the rad is clean inside, and all the gills are present and in good shape. The only real way to know is to try it and see. If she runs out, you need to change the rad. Simple.
Edited to add : Header tank ?? That was a mod from the past, although the '90 model minis on have a sort of overflow catch tank fitted to the side of the rad. This is supposed to collect any water overflowed from the rad, and when the cooling system cools down the water can be drawn back into the rad.
These days on my 1380 I run the minispares supercool 2 core rad, use de-mineralised water with WaterWetter and the minimum of antifreeze, it has a thermostat blanking sleeve and the auxilary electric fan wired to a manual switch. I never shut the heater tap, just close the flap inside the car. I've got a capiliary temperature gauge calibrated in deg F, most of the time the temperature hovers about 160-170 F, on the weekend going to Stanford Hall on the motorway it climbed to 190 F. On trackdays I've seen 210 F, but that's generally on the rundown lap and when exiting the circuit at low speed.
>> Edited by phil hill on Wednesday 30th June 08:30
Spot-on as usual, Phil.
On my rally car I use a standard Cooper 'S' radiater, although all standard rads are what was once the Cooper 'S' rad.
I use a 6-blade fan plus an electric fan, but only find a need to use the electric fan, which is manually switched, on very hot days or when in a queue to start a test or stage.
It always seems that if a 1275 engine can be kept cool there is no problem and when moving it is not a problem. the problem I have had is that if a 'big' engine does start to get hot it is difficult to bring the temp down again quickly.
On the 1991 Cooper I'm building for rallying I'm fitting the new 2-core rad, so we shall see as I have not used that configuration before.
On my rally car I use a standard Cooper 'S' radiater, although all standard rads are what was once the Cooper 'S' rad.
I use a 6-blade fan plus an electric fan, but only find a need to use the electric fan, which is manually switched, on very hot days or when in a queue to start a test or stage.
It always seems that if a 1275 engine can be kept cool there is no problem and when moving it is not a problem. the problem I have had is that if a 'big' engine does start to get hot it is difficult to bring the temp down again quickly.
On the 1991 Cooper I'm building for rallying I'm fitting the new 2-core rad, so we shall see as I have not used that configuration before.
I was with someone only last week who has tried just an electric fan. He boiled it up on the way to Beaulieu the other week and now has to re-fit the 'proper' fan.
I'm sure it would be posible to use an electric fan, but I reckon you would need one with a lot more power than the standard auxiliary one and much coarser blade pitch, so it would take lots of electrical power to run it.
Peter
I'm sure it would be posible to use an electric fan, but I reckon you would need one with a lot more power than the standard auxiliary one and much coarser blade pitch, so it would take lots of electrical power to run it.
Peter
The 6-blade is better than the 2 or 4 blade.
You can get fans which reduce their pitch at higher revs, but the problem with the Mini layout is that you need lots of air flow through the rad at high revs, so you still need the course pitch.
On bigger Mini engines the cooling is always a bit critical. Just a simple thing like a bent manifold down pipe can cause overheating. It's sort-of on the limit.
One thing not to do ever is crop the ends of the blades to get more clearance to the shroud. With a ducted shroud, which is what the Mini is, the end 10% of he blade does most of the work. On rally cars where you can hit big bumps and risk the fan hitting the shroud there is a temptation to rduce the fan diameter. Don't - what you should do is to remove the rubber rad/shroud mountings and bolt the whole lot up absolutely solidly.
You can get fans which reduce their pitch at higher revs, but the problem with the Mini layout is that you need lots of air flow through the rad at high revs, so you still need the course pitch.
On bigger Mini engines the cooling is always a bit critical. Just a simple thing like a bent manifold down pipe can cause overheating. It's sort-of on the limit.
One thing not to do ever is crop the ends of the blades to get more clearance to the shroud. With a ducted shroud, which is what the Mini is, the end 10% of he blade does most of the work. On rally cars where you can hit big bumps and risk the fan hitting the shroud there is a temptation to rduce the fan diameter. Don't - what you should do is to remove the rubber rad/shroud mountings and bolt the whole lot up absolutely solidly.
Tpi cars have no engine driven fan. They use a front mounted alloy rad and electric fan.
I've seen alloy side mounted radiators that are supposedly more efficient than the 4 core or special 2 core rads.
Do you think one of these side mounted alloy rads could be used with an electric fan only?
Neil, the front mounted rad solves the problem as, so long as you are moving, air will pass through the rad. With any side mounted rad you will need to actually blow the air through it at all times. Even an un-shrouded fan doesn't do the job properly.
Maybe twin electric fans would work, but you would need a very powerful inner fan to give the same airflow as the belt driven ones. That would take as much power and load up the alternator and its belt. Looking at it mathematically, to remove a given quantity of heat requires a given volume of air in a specific time period. The energy to move this volume of air will be the same no matter what type of fan drive you use. So, logically, you will have the same drain on your power. However, if you do it electrically you may be able to spread the load over a longer period. The problem may be the ability to generate sufficient power when using headlights, heater blower, heated rear screen, etc, then asking the electrical system to generate another few horsepower/watts to drive one or more electric fans. Total power absorbed will always be the same.
You might get away with electric fan drive if you mount an additional front rad in addition to the side rad and with its own fan unit. Then you've increased the total 'heat-sink' area and put a rad into the airflow, i.e. just behind the grille, and added artificial airflow with the extra fan.
It's a bit of a critical area IMHO and I think staying with a 6 blade fan to be the safest thing to do. My '64 car has a standard 'S' rad, a 6-blade fan and an electric fan and a 13-row oil cooler and it still gets very hot sometimes. I guess the long sump guard doesn't help there, even though it has big holes in the front.
I hope that helps a bit,
Peter V.
Maybe twin electric fans would work, but you would need a very powerful inner fan to give the same airflow as the belt driven ones. That would take as much power and load up the alternator and its belt. Looking at it mathematically, to remove a given quantity of heat requires a given volume of air in a specific time period. The energy to move this volume of air will be the same no matter what type of fan drive you use. So, logically, you will have the same drain on your power. However, if you do it electrically you may be able to spread the load over a longer period. The problem may be the ability to generate sufficient power when using headlights, heater blower, heated rear screen, etc, then asking the electrical system to generate another few horsepower/watts to drive one or more electric fans. Total power absorbed will always be the same.
You might get away with electric fan drive if you mount an additional front rad in addition to the side rad and with its own fan unit. Then you've increased the total 'heat-sink' area and put a rad into the airflow, i.e. just behind the grille, and added artificial airflow with the extra fan.
It's a bit of a critical area IMHO and I think staying with a 6 blade fan to be the safest thing to do. My '64 car has a standard 'S' rad, a 6-blade fan and an electric fan and a 13-row oil cooler and it still gets very hot sometimes. I guess the long sump guard doesn't help there, even though it has big holes in the front.
I hope that helps a bit,
Peter V.
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