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MG MGA - Get Felt - stay cool??
|I have just fitted a new felt buffer to the underside of the bonnet. I believe it was factory fitted to all cars to force more air through the radiator. On most MGA's this has been discarded years ago. I will report results after our next heatwave later this week!! |
The felt strip is glued to the bonnet above the radiator, it is 28mm.(1 inch)thick, 90mm.wide and fits between the two longitudinal bonnet stays. It seals the gap effectively.
I had it specially cut at a business provocatively signed - "Get Felt".
I have 4 extra pieces to pass on at cost plus postage.
First in - best dressed!
I ordered this same piece from Clarke Spares when I ordered my seat belt mounts a year ago - it seems to work fine on my car - never goes above 180 C on the open road and 190 C in traffic, even in our hot conditions of + 30 C.
|Overheating is a vexed question with MGA's. I have owned my 1600 roadster and my 1600 coupe for over 30 years and have tried everything, but the problem appears to stem from not enough air through the grille (note that Mk 2's had an air dam arrangement and factory competition cars had a lot of grille bars removed if it looked like being warm). I have the cores rodded out every three years or so and this allows me to get by reasonably well. We took our roadster to the UK in 1996 and noted that quite a few UK MGA's had electric fans fitted, no wonder we have overheating problems here in OZ (41C is predicted in two days time!).|
As you are well aware from your recent Grand Tour Britannia we do not have the same climatic conditions as you! However, I have never found those horse hair blocks made the slightest bit of difference. I ran without them for about 5 years before I became aware of their existance and purpose. Once installed, I could not see any difference. Then, a couple of yoears later I noticed that a couple of blocks had parted company with the bonnet. Again, no difference noticed, so I have not bothered replacing them.
On another tack, a few years ago, while riding shotgun in my colleague's MGA, monitoring for overheating causes, I removed the gearbox rubber bung from the tunnelling while on the move. The result was staggering: A massive blast of hot air shot into the cockpit and the temperature gauge dropped between 5-10 degrees. If it was not for the fact that the cockpit then got very hot and smelly (oily fumes) I would recommend it as a counter engine boiling measure. Perhaps what is needed is a chimney stack welded to the tunnel!! - may all who sail in her... etc!
I like your idea of an engine heat vent, it seems the ones installed already (chrome vents next to bonnet) are next to useless.
Maybe an experiment with some F1 style exhaust stacks is a nice idea as these create a low pressure in the exhaust at speed.
Has anyone tried to put such venturi effect modifications onto the MGA bonnet vents to see their effect? I think that the vent would need to be drawn over to the side of the car as otherwise the windscreen turbulence would counteract any effect.
There is an interesting article on MGA airflow at this site: http://rutgerbooy.nl/MGA_specials_page_2.htm Scroll down to the foot of the page.
Quite a lot has been said on this site previously about the intakes on the top of the car and airflow in general. My gut feeling is that air pressure underneath the car remains high compared to engine compartment pressure. Also, air goes into the upper vents when the car is moving, leaving nowhere for hot air to go other than into the carbs. Creating that hole in the tunnelling allowed the overpressure engine compartment gases to escape. Anyone who has not sealed up the various holes and periphal gaps in the firewall will be aware of the blast of hot smelly air that migrates in the cockpit.
I guess what you really need is some sort ducting system from the firewall into the chassis square section tubing and out the rear end. The bonus is that you would have a centrally heated chassis for those really cold winter days!
Sorry Barry, I hope I have not hi-jacked your topic too much.
|Hi all , I replaced the horsehair pad on my bonnet and I would think on it's own it probably does not make much difference but each little improvement you can make will overall improve things if you are having problems , obviously for a show car it needs to be in place|
|g c pugh|
|You're right Gordon, every little improvement helps. I have had overheating issues since owning my 1600 in 1997. Over time I have:|
1. Fitted a summer thermostat - better than nothing as purchased.
2. Had the block & head waterways cleaned out. No difference.
3. New water pump. No difference.
4. New (Chinese) MGA radiator. No difference.
5. When new Rad leaked, new 'better' core soldered in. N.D.
6. Cut back fexible ducts to get max air flow to rad. N.D.
7. Twisted front grille to best alignment for airflow. (also better alignment with body's curve) N.D.
8. Fitted a rubber seal (instead of correct felt type) as I had a length which could prove the point. N.D.
9. Tried Optimax and still use 99 octane V-power fuel, as I felt the '95' unleaded stuff and retarded ignition must make things run hotter.
All the above was trying to maintain originality, I then tried a Fan Cowl from LBC Co, USA. N.D. Fan cowl later removed, as there was poor accessibility.
On hot days I found I had to drive at 45mph. Faster or slower and up went the water temp.
The real problem was in traffic hold-ups on hot days, where not only do we get high water temps, but also fuel vaporisation; so I finally succumbed and fitted a manually switched Kenlowe fan, leaving the supplied thermostat in the box. This works very well in those hot jams, keeping things down to 180-190 deg F. I powered it using the loom's fog light wire.
The one thing I haven't tried is the thicker (2") radiator which I believe Bob West fits and maybe nearer to original???
Hope all this, not very useful info helps someone, but I guess the car is that bit better nowadays.
|hi pete i also have a manual kenlow fan fitted which was fitted by the p/o which works very well in keeping the temp below 180 even in the summer/ traffic, although i have tried it without using it and never overheats i.e. boils over , never seen the temp go above 212, but it does suffer with fuel vapourisation after i switch off , this has been reduced somewhat by using superunleaded and some millers fuel addititive which also stopped it running on|
|g c pugh|
In my humble opinion a radiator as close as possible to original spec would probably have cured your problems at item 4. I fitted the Bob West radiator after my original finally sprung a leak and it works just fine. I could not see any changes to the running temperature. It is just about as close as you can get nowadays to the original.
I am sure alot of others will have a go at me for saying this, but I am of the opinion that about 80% of the overheating problems we read about (40+ degrees in Oz excepted) are due to the fitment of unsuitable modern radiator cores.
My colleague (mentioned in my earlier post above) finally took his replacement (Chinese?) radiator over to Bob and brought home a Bob special. Problem sorted at a stroke.
I have just looked under my bonnet. The strip you have put in only covers the central raised section of the radiator, leaving about 4 inches each side. I used my kit to cover the entire width, although it is some of these bits that are now probably lying in the guttering of the M6!
|Thanks for all that you lot! I guess the true test will be when I get the car out in traffic on, what we Downunder call, a HOT day. I have not had an overheating problem with this, (the 4th) motor, in my 37 year odyssey in this old banger. |
I am inclined to Gordons comment re 'every little bit helps' and it is a point winner on a show car. Many cars entered in our local show event do not have the buffer fitted and many drivers are not aware of its existence.
Steve we could have made good use of all that accumulated hot air to heat us on that bloody cold dash to Bob Wests last Nov!
Where would we be without this forum?
|Pete, one item you did not list is the fitting of a plastic 'aerodynamic'fan. I replaced my metal paddle with one and the extra airflow drawn through the radiator is impressive. The fan ends up closer to the radiator and my mga never gets anywhere near boiling in summer traffic at slow speed. At higher speeds the gain is less since the ram effect of the ram airflow exceeds the fan suction. I am an advocate of sealing the area in front of the radiator including the gap next to the tray at the bottom. Replacement radiators often have their cooling fins spaced quite a lot closer than the original and there must be a balance between the airflow through the radiator that is proportional to the cooling capacity and the increased frictional resistance to the airflow. I have a feeling that the modern replacement 'tight' radiator with close packed fins is less efficient than the original more open radiator. Hence the need to push as much air through it as possible. I have heard that Moss radiators are now very similiar to original but if you use a radiator 'specialist' this may not necessarily be offerred.|
|J H Cole|
I am sure a "downunder" HOT day is a tad up on a HOT "up'n over" Pommie day isn't it mate! (Northerner Steve only does cool doesn't he Mr Pugh)
Has your water temperature ever got up to 100psi yet? (See gauge) Mine did getting to the Parade des Pilotes at Le Mans one year - the rad cap cried enough and we dumped loads of coolant, the right way, out the over-flow tube! Took most of my drink bottle to top her up after that!
Tell me more about the aerodynamic fan blades.
|Pete, I think you meant 100degrees rather than 100psi. I run a 7psi cap and have an overflow tank from an Austin 1800 as an extra reservoir. It is one of the older tanks, about 1 litre, and is brass. Polished up and laquered, it looks quite good and, more importantly, it seems to work in our high temps.|
Steve sure is 'Mr.COOL'
|Steve, your comment on the exit of hot air from the engine bay is one of the problems I have tackled. Coupled with the fire wall getting very hot, I insulated the fire wall from the bonnet down to the bottom of the body [BOTH SIDES ] and blocked off the|
area below the exit vents. When the electric fan runs there is a strong stream of hot air from both vents, ie. the hot air is now forced to exit at the top where it gathers and the cabin is now comfortable.
Also if your car has a heater, think about removing it for the summer and piping ambinent air from the front to the cabin vie a right angle 4 inch connector through the blanking plate that is fitted to cars without heater. Works well on the move, I will sort out a fan one of these days Cheers Sean in Aus
|Today is great day for testing your cooling system in Melbourne 42 deg C!|
|The less obvious ways to solve cooling problems :|
1) fit a ported cylinder head to improve breathing
2) fit a supercharger
My car (which had never overheated anyway) runs a steady 70C in summer, and struggles to achieve operating temp (50C) in winter unless I block part of the radiator
Rad core is to original spec too, as with the SC I knew that a high capacity one would cause problems. Having had a number of Moss reros start leaking, I would suggest avoiding these.
|Steve, I've been trying to find the original detail I used for the fan conversion but I can't lay my hands on it. I think it may have came from an early MG Owners Club 'tech Session' but I can't be sure. Anyway I used a yellow 7 bladed plastic fan from a Marina bought second hand. Two holes have to be drilled to make the fan correspond with the screw holes in the pulley. The fan sits slightly more forward and I had to fit double felt packing for the radiator mounting to move it forward and give clearance. The job was done in a couple of hours. As I said there is much more suction and its quietier than the metal blades. The operation is fully reversible if you don't like the end product.|
|J H Cole|
|Just checking, but do you have an oil cooler installed? It helps, plus reduces the chance of oil temp break down at high temps. |
The thermostat sleeve with a thermostat helped as well.
I have heard that Jet Coating or simular the exhaust manifold helps, anybody have experience with that?
This thread was discussed between 08/01/2008 and 10/01/2008
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