12 replies to this topic

[Minigirl]

what size water pump pulley do I need for a 998 to fit the 940 head? Thanks

[Minigirl]

Anyone?

[panky]

I dont think there's any problem with using your old standard one if you still have it

Edited by panky, 08 December 2016 - 11:56 PM.

[carbon]

I would fit the largest water pump pulley which does not foul the 940 head, unless you're expecting to sit in heavy traffic a lot of time in which case a smaller one may be better.

[tiger99]

If in doubt, see below:

 

http://www.somerford...page=page&id=97

[Minigirl]

Just measured and it seems to be 3.95" the pulley that it on. I. Guessing that will be OK with a 940 head.... But is this also why the heater in the car isn't very warm?

[RooBoonix]

Just measured and it seems to be 3.95" the pulley that it on. I. Guessing that will be OK with a 940 head.... But is this also why the heater in the car isn't very warm?

No, a cold mini heater is a standard feature on minis.

Joking aside, a cold heater can he caused by a stuck heater tap or a blocked heater matrix. Unless your water pump is spinning way too fast and causing cavitation (I think that's what it's called) where basically the water pump is just cutting through the water rather than pumping the water, which is rare in a standard car, then you may he better off checking the operation of your heater tap and back flushing your cooling system to make sure there are no blockages.

Hope that helps
Cam.

[Northernpower]

Just measured and it seems to be 3.95" the pulley that it on. I. Guessing that will be OK with a 940 head.... But is this also why the heater in the car isn't very warm?

No, a cold mini heater is a standard feature on minis.

Joking aside, a cold heater can he caused by a stuck heater tap or a blocked heater matrix. Unless your water pump is spinning way too fast and causing cavitation (I think that's what it's called) where basically the water pump is just cutting through the water rather than pumping the water, which is rare in a standard car, then you may he better off checking the operation of your heater tap and back flushing your cooling system to make sure there are no blockages.

Hope that helps
Cam.

Standard water pumps will cause cavitation at high rpm but the evolution water pump sold by Minispares has been tested on their test bench to 11,000 revs and does not cavitate. I've seen the test video footage.

[panky]

Does the engine reach it's normal operating temperature? if so then as suggested check the heater and hoses for restrictions, and wear jumper

[tiger99]

I doubt very much that cavitation is causing your heater to underperform. Most likely it just needs a good flush, a check for flattening hoses, and carefully bleeding out any trapped air. They can be at least adequate, even in very cold weather, when everything is in good order. But Minis are all very old now, so they are going to need attention from time to time.

 

But I an sure you don't want too small a pulley anyway, as you don't want to be wasting otherwise useful power spinning the pump faster than is necessary. Provided that the cylinder head temperature remains acceptable under all operational conditions, the pulley can be enlarged to reduce the pump speed.

 

The ECUs that I am involved with at work are for large modern turbodiesels and the practice there is to either use an electric pump or an electric clutch or electrically controlled pneumatic clutch on a mechanical pump, often with two speeds available. The fan speed control is also from the ECU. Whether using an ECU or not, the idea of an electric pump has much to commend it. Going off topic I know, but I would like to see electric coolant pumps becoming more widely used on Minis, as they have so many advantages, if of adequate quality. Faster warmup, less power loss, no poor quality thermostat problems, less reliance on fan belt.... The big ones, like the ECU, are designed for a million mile life. Sadly a 12 litre 700 bhp monster is not going to fit in a Mini!

 

The big diesels use a CCV (Crankcase Ventilation) pump too, again ECU controlled and monitored. A good way of keeping negative pressure in the crankcase and minimising oil leaks, as well as improving emissions. There may also be an electric oil pump for initial startup, and to keep up pressure while the turbo is still spinning after shutdown. There is no reason why these modern innovations should not start to creep into Minis. Plenty of opportunities for small scale manufacturers to do things correctly.

 

Coming back to the heater, some modern cars use what is basically a diesel engine glow plug screwed into the hot water feed pipe to the heater. It is turned on only when the water is relatively cold and the alternator is generating adequate power, to avoid killing the battery. It simply tries to feed hotter water into the heater. Simpler and safer than having electric heating elements in the cabin. Could be retrofitted to any car.

 

I hope that some of you will find these suggestions useful one day.

[RooBoonix]

Just measured and it seems to be 3.95" the pulley that it on. I. Guessing that will be OK with a 940 head.... But is this also why the heater in the car isn't very warm?

No, a cold mini heater is a standard feature on minis.

Joking aside, a cold heater can he caused by a stuck heater tap or a blocked heater matrix. Unless your water pump is spinning way too fast and causing cavitation (I think that's what it's called) where basically the water pump is just cutting through the water rather than pumping the water, which is rare in a standard car, then you may he better off checking the operation of your heater tap and back flushing your cooling system to make sure there are no blockages.

Hope that helps
Cam.

Standard water pumps will cause cavitation at high rpm but the evolution water pump sold by Minispares has been tested on their test bench to 11,000 revs and does not cavitate. I've seen the test video footage.

Thanks for clarifying, I was unsure if they did cause it or not. Nonetheless it's not a common enough occurrence to cause issues day to day and is unlikely to be the cause of the OPs cold heater unless he has a very small water pump pulley!

[Northernpower]

Just measured and it seems to be 3.95" the pulley that it on. I. Guessing that will be OK with a 940 head.... But is this also why the heater in the car isn't very warm?

What temperature thermostat are you using?

[Minigirl]

I think its a 82 or 83 but just got a 88 deg one from minispares to go it when it put the 940 head on,

Both water heater pipes inside the cabin get hot so surely its circulating? Or maybe not circulating fast enough? I know the matrix isn't blocked as I had that off not long ago

Thanks