MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Simple way to reduce engine bay temperature?

I remember a while back there was much discussion about fuel vaporisation. Like a number of others, I fitted a bilge pump to help cool the carbs.
But I remember some people said the real solution would be to increase the flow of hot air away from the engine bay rather than to force more cool air in.
With summer coming up I was thinking of trying this very simplistic idea. I was thinking if I removed the wide airhose running to the heater and switch on the heater fan whenever in traffic, it would help expel air from the engine bay to the cockpit? I will obviously need to block up the aperture along side the radiator to prevent air by-passing the radiator. I never use the heater fan anyway, so wouldn't be bothered to "lose" it.

I realise that the cockpit might get a little warm, but if it works, I might be prepared to put up with that to avoid the spluttering in slow moving traffic

Would it work do you think?

Graham
g Victors

Always worth a try Graham. However, the hot fumes you will be putting into the cockpit will not be very healthy for the lungs!

Steve
Steve Gyles

Graham,
I suspect that is tantamount to treating the symptoms rather than the problem.
You don't say what your bilge pump is doing but with an effective electric fan on the radiator and the two vents at the top of the engine bay, the temperature should be under control.
if you are having problems with fuelling, the HS4s must be suspect.... after all the temperature in the A's engine bay hardly compares with the GTV8 which has two exhaust manifolds (and two fans)
...anyway the flow through the heater fan is not high enough to make much difference.IMHO
Roger
Roger Walker

Roger

The two vents you refer to are in fact intakes. In motion, air flows from outside to in. Only when stationary is there a slight outwards drift of air.

Steve
Steve Gyles

Steve,
Absolutely but the overheating occurs when stopped in traffic.
Roger
Roger Walker

Roger
Funnily enough I fitted an electric fan today. But the bilge pump is fitted in the air trunking pointing at the carbs. There is lots of details in the archives and on Barney's site.

Steve
I will definitely try it out when the weather gets warmer and report back. If it works we could design some sort of Heath Robinson device to deflect the fumes away! But it shouldn't be too bad? Not exhaust fumes hopefully.

Graham
g Victors

Hi Graham,
I have both a 1500 standard engine fitted with a Maniflow 3 branch exhaust manifold and 1600;the 1600 being fitted with a 1950 crossflow headed engine and neither of the suffer with problems, at 40 in traffic at Le Manns the 1500 coped very well.
On the 1950cc engined 1660 I purchased some Twin Cam inner wing louvered panels from Bob West cut the inner wing out to fit and engine bay cooling problem is solved. The car runs at about 170 degrees normal use, but rises to about 190 degrees in traffic when the electric fan cuts in
David Speak
D M SPEAK

Graham,
Mine is a 'daily driver' through central London - so I empathise - and have done all that I can to keep heat at bay. My approach has been to recognise that I can't fight the inevitable equilibrium, but I can at least try to establish a more comfortable one. Some of the factors I list below might work for you. I have tried to get air in (to engine bay and carbs) at least as fast as heat out.
Best thing that I ever did (after following Barney's rules for connecting all hoses, plugging gaps etc) was to fit twin electric fans (with override). Other features I have which might have helped include (i) exhaust wrap (ii) 'red water' (iii) free-flow exhaust (iv) bigger / freer-flowing air filters combined with (v) (prior to the availability of Steve's excellent stub stacks) MGB equivalent (a pair is up on EBay at the moment). One additional factor you may like to consider is to try to reduce combustion temperature. For a while I ran with TetraBoost lead additive (prior to fitting unleaded head): that might just help a bit.
Whilst my suggestion is to try to attack the equilibrium, if I get nervous I do turn up the heater. But all that might be left after that seems to be bonnet louvres - if that suits your style. I'm not sure that they would necessarily do much more in slow traffic than postpone your current inherent equilibrium, but that might be enough. Might be worth asking around.
D
D Smith

A couple of us downunder run louvred bonnets on our As and have no trouble with overheating. Also they look cool!
Mike
Mike Ellsmore

I now run my mga with two 9" electric fans controlled from an electronic thermostatic switch in the top hose and I have removed the engine driven fan.
They are well capable of bringing the engine temperature down from what I consider hot (210 degrees F) to 190 degrees in about 3 mins.
( my car only gets this hot when it is stuck in traffic, out on the open road it runs between 165 and 185 degrees)

I have experimented with a more efficient design plastic engine driven fan, which was a great improvement on the standard metal fan but was irritatingly noisy.
I also tried a single 10" diameter electric fan but I found that it struggled on its own to keep the engine temp under control.

My present dual fan set up is excellent and I think they work so well because they move such a lot of more air through the rad and help push much more hot air out of the engine bay.

I wrote up all the results of these experiments for Safety Fast magazine but I think it was a little too big an article for them to find space for.
If anyone would like a copy just email me for one.
Colyn
I forgot to mention that I have the twin cam inner wing louvres, louvres in the bonnet and an oil cooler under the radiator duct panel.
c firth

I'm thinking that sucking engine bay fumes into the cab via the heater fan is a good way to make the passengers not worry about the rough idle
I reckon your problem is more mixture related, where the car is running a tiddle on the rich side which you normally get away with but when in hot traffic it shows up
Have you thought of the possibility of building/buying an inclosed inlet housing for your carburettors complete with cold air ducting from infront of the radiator, instead of pulling warm air from the engine bay
willy
William Revit

I would argue stronglyy against using the heater fan and sucking air into the cockpit. The fan is piss weak and the fumes ...ohhhh the fumes ! Twin fans plus a bilge blower gets me by on hot days and standing in traffic. If more is required then remove the heater hose in summer ( does mIddlesex have a summer?) and fit another bilge pump on the other side of the radiator. Many other good ideas above..incl. wrapping manifold some of exhaust. ..but stay away from the heater...
Neil Ferguson

Yep
All it takes is a small exhaust leak, and pumping it into the cab makes for one sleepy driver--or a dead one
It's happened--DON"T DO IT
willy
William Revit

I have the heater set to full all the time - in the winter it helps keep my toes warm and in the summer it takes a little heat from the engine. The long hose is still in place.
Dan Smithers

Graham

As others have intimated sort out your radiator first. In my opinion there is barely the need for radiator fans in the UK. My 1800 engine runs at 170 to 175 all day with an original spec radiator.

Steve
Steve Gyles

I have just come back from a week travelling in the A around eastern Austria and western Hungary. 70C all day long, uphill, downhill, fast, slow, in traffic (traffic jam in Vienna last night because of the opening of Eurovision) and on the open road. There's nothing wrong with a standard MGA cooling system if the radiator is OK.

The new reproduction radiators are rubbish, get yours recored and make sure the core is to the original specification and not a higher density one that doesn't allow enough air through with the standard fan.
dominic clancy

And here's a picture of all the A's including some from the Hungarian MG Car Club - the strange coloured one is apparently the original Alamo Beige according to the owner


dominic clancy

Hi
Thanks for all the advice. I take it all onboard and wont risk the fumes in the cockpit. It was just a thought!
I have only just fitted an electric fan so my first step will be to see how that affects things.
But you guys must be psychic as I do need to get my radiator sorted; that will be next. It has a couple of repairs on it so I guess I am not running on full capacity.

Thanks, Graham
Graham Vickers

Graham, I was having a problem with vaporization in my (new to me) TD. I changed everything under the hood (bonnet) to try to end the sputter to a stop syndrome. ...Wait 5 to 10 minutes and we're on the road again.

The gang over in TD/TF forum have been very helpful.

I made a shield and am hoping this solves it. So far 35+ miles and no sputter. If not, I'm at a complete loss as to what to do next.

The carbs are noticeably cooler to the touch - perhaps 20 or 30F cooler.

Also, I'm hoping switching to non-ethanol drives the last nail.

....


MAndrus

Good point MA
Graham--Is your car fitted with a heat shield ?? and insulator blocks between the carbs and the manifold

willy
William Revit

While we seem to be drifting a little off the originally posed question, I second the comments of Steve and Dominic and others. There appears to be no need for supplementary radiator fans in an MGA, IF the radiator is working to spec. The original V cell (aka "cell core") radiators appear to have less impedance to air flow than the current styles of cores, and these original style cores seems to work better with the cramped nature of the MGA engine bay. Not having easy access to such a V cell core, I achieved a similar result with my MGA using a custom made aluminium radiator, single pass, single row, marginally SMALLER than the original. Even at high ambient temperatures (circa 35 Celsius), I have no issues, no matter the traffic conditions, long uphill climbs etc etc. No radiator fan/s, no carburettor air duct fan. And it sure gets a hell of a lot hotter here in Australia than those in the UK would ever dream of. I don't believe I've ever seen over 185-190 on the gauge since fitting the aluminium radiator, even in the most provocative circumstances. Most of the time the temperature gauge needle seems to be "bouncing" on and off the thermostat as it opens and closes.

On another note, Dominic, I'm amazed to see the number of MGs, especially MGAs in Hungary. (And unlike Australia, they're not 70% red, 15% BRG, and 15% other colours, which is most refreshing to see). I had no idea there was such a large MG scene in Hungary. I'll be there with one of my daughters for about a week in July, visiting my last surviving Hungarian relative, my 88 year old aunt. Despite visiting four times since 1974, I'd only seen one MG there before, in Budapest, a MK I MGB, during my very first visit.
T Aczel

Only Three of the cars are from Hungary, the rest of them are from the MGA Club of Switzerland.

dominic clancy

What made a huge difference in engine bay heat for me was installing a Maniflow tubular header with ceramic coating on the outside and the inside. The heat just passes through and out the exhaust generating very little radiant heat.

Steve Meline
Huntington Beach CA
Steve Meline

Steve...was that an APT manifold and did you have to do anything special to install it?
Gene Gillam

Yes Gene, APT. Dave charged extra for the ceramic coating, worth it. It was installed during a rebuild, but no problems reported.

Steve Meline
Huntington Beach
SAM Meline

Thanks!
Gene Gillam

This thread was discussed between 17/05/2015 and 10/06/2015

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.