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MG MGA - transmission heat
|I went to Key West this year with NAMGAR and we had a great time. On the way down on Sunday afternoon it was hot and with the traffic on I95 it got even hotter. When I drive my right leg has a tendency to lay against the stick of the gear shift. When I got there I had a big blister on my leg from the temperature of the stick. I am using 20-50 Castrol in the trany. Is there a different type of oil that would keep the trany cooler.|
|My gearbox gets pretty hot too. I just try not to have skin contact with the shifter during the long drives It has been this way for years and I use 10W-40 generally. No problems...(yet) I don't know of any oils that would make the gearbox cooler.|
|Good lord, what size are you guys? Having read the posts I went outside and sat in my car. I am 175 cm (5' 9"). I have to bring my (left) foot totally off the clutch (RHD car) by about a foot and force my leg across to just make gear stick contact with my knee cap. In a normal driving position I cannot get my thigh closer than about 6 inches to the stick. Also, the top of the tunnelling is way above the level of my leg. I would have to sit on about a foot of additional cushioning to make contact with any ease.|
|HA ha, Im only 5'8". Its only my hand that touches the shifter and it gets hot....not my leg haha...|
|Stupid question but is it possible to add a transmission cooler to an MGA. There are engine oil coolers, power steering fluid coolers and transmission coolers on modern cars...could one not adapt one of these to an MGA. Do any of the vintage racers have some ideas on this?|
|The best way to cool the MGA gearbox is to have some ducting directing air onto the outside of the casing.|
This was done by the factory on some competition cars.
At Le Mans in 1959 the mga twin cam failed to finish because this ducting was damaged and the gearbox overheated.
See attached image of article from the book "Pay-it-Yourself" which is on sale through the MG Car Club North-West Centre U.K.
|M F Anderson|
|I have not seen one at any of the vintage events I attend but who knows. I don't think it would be difficult to add a cooler. All one would have to do is drill out and tap the existing lugs on the side of the case and use an external electric pump to move the oil. It may be easier though for those affected to creat a lambs wool "sweater" for their shifter.|
|Try Racing, then you will know what HOT is all about. Race suit and no carpet... 6 foot 1 and after 8 laps you've got some serious temperatures happening on that gearbox tunnel.|
exhaust tape on the manifolds all they way under the car helps push the heat downwards.
I read in one of the MGB special tuning manuals to take a hole saw to the bell housing and fit some mesh over the hole, then remove the rubber boot of the clutch pivot pin. Thus at least the hot air generated by the clutch can escape and the clutch has less chance of overheating. It seemed to work for me, but what your talking about is motorway heat, rather than racing heat. i.e. not so much generated by the clutch.
Like radiators you can paint gearboxes black to dissipate the heat quicker, but really it's the age old problem with MGA's where the heat does not escape the engine bay quick enough, due to the large skittle area around the heater.
From my knowledge of racing, gearboxes don't seem to mind the heat, only the occupants have a problem with that. Diffs on the other hand can be more sensitive.
Hope you can draw something useful out of this.
|I wrapped my tunnel in insulation and made sure the the filler hole seal is brand new and not leaking any hot air under the carpeting. Still it can get very hot as you describe. I lay a folded towel on the tunnel for the leg to rest on and it seems to provide all the additional insulation I need. As for the stick temperature- I just keep my leg away from there!|
|Mark J Michalak|
|You can tell how much heat is generated down there by removing the gear box filler grommett and opening the carpet flap. You will be amazed at the blast of hot air coming out into the cockpit at speed. It dropped the engine temperature in my car by about 5 degrees, but made the cockpit a very unpleasant environment!!|
In a LHD car your right knee rests on the tunnel when your right foot is on the noise pedal. Why you don't notice the heat/proximity in a RHD car is because your left foot is only occassionally on the clutch pedal, while most of the time your left leg is straight.
When one drives an MGA 400-500 miles a day in North America, you soon learn to have a folded towel over the tunnel.
I usually rest my left leg against the tunnel; helps with the rheumatism! My surprise was that the 2 opening posts were talking about resting their legs against the gear stick. Now that requires some doing.
|When I would take young ladies for rides in my first MGA (purchased while in college), we could find all sorts of ways to contort our bodys in the cockpit. Never did I burn my parts nor those of the young ladies on the gear stick, but then again I do recall some comments about being too hot! My suggested solution then was not to add towels but to remove clothing! I think that somehow today that wouldn't work.|
This thread was discussed between 12/05/2009 and 14/05/2009
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