Efficient cooling in hot conditions.

[johnbuckley]

I'm entering a bog standard 1979 BGT in the Italian MG Club Tour in Sicily this summer. I expect the area to be very hot and very mountainous. Any tips on how to keep the engine temp normal?

[Peter Cresswell]

Hi John
I think your car has an electric fan? If so it might be worth checking the fan thermostat and considering wiring in a manual overide.
The main thing to remember in high ambient temperatures is to keep air moving through the radiator, as this will provide cooling even in 40Deg +. So traffic jams are a real problem. I would take a spare thermostat as part of your kit, and you might also consider a thermostat blanking tube, which does away with the thermostat, but restricts the flow to something a bit higher than having the thermostat in the system.
I think the climb up Etna is the biggest hill on Sicily, and is likely to be a problem because of the slow traffic, and you will have to use 2nd gear a lot. Don't worry to much if the needle goes up towards 'H' or even gets to 'H', as with a pressurised system it won't boil until around 110Deg C, and it will quickly cool on the way down if you use a high gear. The B series engine (and A series for that matter) are pretty robust, and much more so than modern engines (especially a K-Series!). It will normally run a little hotter than in the UK, but where the traffic is flowing freely you should be ok. Hopefully the organisers will have taken into account the needs of old British cars!
One other thing is to consider a more modern semi sythetic oil. This will stay in grade even if the oil temperature gets high. I used Millers CTV in a Mk1 Mini Cooper. I'm not sure if they do a version for cars that don't share the engine oil with the gearbox, but I would assume that CTV would not hurt a B-Series engine as it is ok in an A-Series. It held normal oil pressure even when I boiled the oil climbing the Col de La Bonnet which is the highest road in Europe!
For reassurance he's a picture taken inside the Cooper when the ambient temperature was over 40 deg C and the water temperature was 105deg C. It was still idling at its normal 1000 rpm. This was on the way to the Le Mans Classic in 2010.[attachment=0]Stuck in traffic at Arnage. Water temp 105, but still ticking over at 1000rpm.
jpg[/attachment]

[Peter Cresswell]

I forgot to mention that you can get rid of a lot of heat by putting on the heater to max temp and putting on the blower.

[Jim Haines]

Excellent response from Peter - must have been worrying to see the gauge climb as high as that so far from home.......
Took my own "B" around the roads of France in their hot season twice - not as bad as Italy but warm, nevertheless, so I took advice from someone I knew at the time before I left.
I drained the cooling system and refilled it with a proprietary radiator cleanser which I left in for a week. After that had been done I then changed the top and bottom hoses and the thermostat/gasket and filled up with new antifreeze.
As my car was only fitted with the original plastic fan I bought a Kenlowe electric fan and fitted that as well - a simple job.
I tend to travel at around 50-60 mph and I remember it only came on in slow traffic, and otherwise all went well for us.
Have a good run....

[johnbuckley]

Thanks Peter
Yes the car has a pusher electric fan as OE controlled by an Otter switch.
The fins on my rad have a area where they're gone- so a new rad might be wise in any case- Is there a "High efficiency" rad available? ( late rad with cap on overflow tank). I intend to flush the block as much as poss when the rad's off.
I was also thinking of fitting a supplementary electric puller fan as not convinced of efficiency of the existing one.But presumably the fans only are of use when crawling or stationary.
Where can one get a Thermostat blanking tube from?
Yes I recall driving through central London a few years ago with the heater full on, all windows open, the bonnet popped open on its latch and the engine running really roughly as the temperature mounted! Not an experience I want to repeat!

[johnbuckley]

...and thank you too Jim. Looks like all should be OK so long as every thing is working properly, no sludge in system and a second fan fitted just in case!

[Peter Cresswell]

johnbuckley wrote:
> Thanks Peter
> Yes the car has a pusher electric fan as OE controlled by an Otter switch.
> The fins on my rad have a area where they're gone- so a new rad might be
> wise in any case- Is there a "High efficiency" rad available? (
> late rad with cap on overflow tank). I intend to flush the block as much
> as poss when the rad's off.
> I was also thinking of fitting a supplementary electric puller fan as not
> convinced of efficiency of the existing one.But presumably the fans only
> are of use when crawling or stationary.
> Where can one get a Thermostat blanking tube from?
> Yes I recall driving through central London a few years ago with the
> heater full on, all windows open, the bonnet popped open on its latch and
> the engine running really roughly as the temperature mounted! Not an
> experience I want to repeat!

Both B&G and Moss list the thermostat blanking tube as part no AJJ4012. Costs around £10. Alternaively take another thermostat with some holes drilled through the flange. Both also list a 'Hot climate' thermostat (GTS102) that opens at 74degC instead of the normal 82degC
Moss list both aluminium and Ho flow radiators. around £470 for the Al ones and £270 for the Hi Flow. You will have to be a bit careful you don't end up with a car that is over-cooled in the UK!
You might be able to make up some extension brackets to raise the back of the bonnet to let some of the hot air out.

Sounds like a good event in a lovely part of the world! Are you driving there from the UK?

[johnbuckley]

Thanks for the info, much appreciated.

[Dave Linkson]

In very hot ambients, if you are slogging up a mountain, you are generating a lot of heat, but the slower passage through the air and the high ambients means the radiator isn't dissipating as much heat as at other times. The thermostat is already wide open, so the coolant continues to get hotter and hotter, and the temp gauge rises inexorably towards the H zone. In this case an additional or even replacement electric fan may give more cooling, if the volume of air moved by the electric fan is going to be greater than that moved by the mechanical fan. But you need to consider motor revs against engine revs, and comparative efficiencies of the blades. Another aspect of electric fans often not considered is the blocking effect of the blades when the fan isn't running. Whilst it's true that the fan will almost certainly be 'windmilling' when the car is under way this takes energy out of the air-flow, slowing it down, and a significant amount of air will be flung off the tips of the blades. If the fan is in front of the radiator i.e. a pusher both these aspects are going to reduce the amount of air passing through the radiator. If behind i.e. a puller then at least the air will have passed through the rad before it is flung off, even if there is still some back-pressure reducing the air-flow through the rad slightly. Factory fans were always pushers, and the left-hand fan (when looking into the engine-bay from the front) on twin-fan installations is particularly inefficient as part of the arc described by the fan isn't pointing at the radiator anyway.

[Jim Haines]

What Dave says is clearly correct, but surely the way to maximise the effect of any pusher fan is simply to adjust the thermostatic control so that it kicks in at a lower temperature?
The original plastic fans fitted to the MGB were, at best, adequate for normal cool road conditions prevailing in the U.K. when the design was finalised in the late 1950's - early 1960's, but Mr. Average with his heavy right foot soon made a mockery of these standards and therefore a market for supplementary electric fans was created
Mine has worked fine since I installed it some 15 years ago, and I learnt that summer motoring warranted a slight adjustment to the thermostat in hot weather.
Stand by the side of the road at traffic lights in the U.K.summer now and listen to all the 'moderns' fans kicking in while they wait for the lights to change to green............