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MG Midget and Sprite Technical - Exhaust heat

I have a 75 with a header. A passenger was complaining about the heat in the feet area.
What is the best why to bring down the heat transfer?
Wrap the exhuast and put insulation between the two?
RC Bishop

I had the same thing in my 78 before I converted it to a 1275cc. You need to look at the air space between the exhaust system and then body, if its close you need to add space and wrap it. On the 1500 it comes out the right side so more air flow there helps but if you already have plenty of space between the exhaust system and the cockpit the only way to go out be wraping the exhaust....

I am assuming you have installed an interior in the car and there is another posibilty and that is to install extra insulation between the carpet and the floor pannels.

Stefan

Bishop, i would prefer Stefans 2nd option to insulate the footwell insted of wrapping the exhaust.

I had my exhaust wrapped but then found out the hardway it didnt do good for the manifold(metall-burn).

Best way is to tell the passenger to stop wyning!
Once you were in a Kseries engined midget the heat of a 1500 is a laugh really. :)
Arie de Best

Arie, heat is greater with K or less?
Paul Clark

Greater.

My 1500 had the exhaust run under a little part of the footwell and under the gearbox to the lefthandside under the seat.
So the righthandside seat(passengerside on my car) had some heat but i cant remember of the few times i sat there that it was that hot.

Now i have a K engine the exhaustmanifold is in front of my footwell and the exhaust runs under my footwel and seat.
That does give a lot of warmth still dooable.
However the not so nice heat comes from the heaterflaps in the footwell when the heater is switched on.
When you ware sandals/slippers this heat is unplesant on your bare skin.
Your skin doesnt come of yet but since then i dont have hair on my feet anymore. :)

I havent installed a operational switch to operat or shutoff the heater.
Oh, and i did cover the part of the footwell inside the engine bay thats near the exhaust with this stick-on aloy heat protecter sheat.
Arie de Best

Forgot: even with the heaterflaps shut in the footwell hot air still comes in as the flaps dont shutoff very well.
Arie de Best

A good cure I did 2 years ago, was I pulled the smith heater box and got an aluminum dryer hose and hooked it into a box screwed down over the heater hole, sealed with some foam tape and ran the other end as it should be to the front, the purpose of the aluminum hose is it will repel heat, not attract or allow to soak.


The faster you drive the cooler the cockpit area. I never got around to installing a fan, but that would help....The reason for loosing the heater box was 2 fold...it collects heat from the engine and transfers it, and the heater matrix restricts cool airflow, just remember the air that comes in is only 2-3 degrees cooler then the outside air temp. so if its 102 degrees its still 100 degrees hitting your legs and feet, but it is moving air that helps get rid of the exhauste heat.

I really think fender heat vents will solve a vast majority of these heating issues

Prop
Prop

RC:

Hot is a relative idea. No catalytic converter, Washington state, sounds like happy feet to me! Arie's got it right I think: A: footwell insulation B: No whining from the passengers. FWIW I just spent the better part of the last week outdoors, swapping out engine/gearbox. Daytime highs were 101 to 107 all week.

It's very hot
Time to pull the gearbox!
Someone shoot me

R
Richard 79 1500

RC:

Forgot to mention: It probably wouldn't make enough difference for passenger comfort, but retarded timing will make your engine run a bit hotter.

R
Richard 1500 5 speed

Indeed; as would a cam that opens the exhaust valve early (i.e. fast-road/race cam).

Some law of thermo says that the more work the exhaust gas does (and the larger its volume), the cooler it will be.

My wife complains her feet are baked in the footwell of my car. I say (but not to her face) it's the only time your feet aren't cold!

A
Anthony Cutler

OOOOGH Ant, very daring to say of you, you realize this could cost you half+a bit more of your possesions? LOL
Arie de Best

thanks for the help.
My exhaust is about 4or 5 inches from the footwell.
It my just be complant from this one person as I have had others as passengers with no complaints.
I have also improved the flow of air from the front air ducting thru the heater coil.
My exhaust goes under right behind the oil pan & down the drivers side, and I feel no extra heat.
The timing is correct as she runs very well and the Water gage stays right in the middle and a little above on extended 60mph runs.
If I get any more complants I'll put in some insulation behind the carpiting.
RC Bishop

I am told that a sheet of aluminum mounted on standoffs halfway between the exhaust pipe and the body will help a LOT.
David "haven't gotten around to trying it yet..." Lieb
David Lieb

Stefan's first option was best - put a 1275 in it!
Shawn

David's heat shield works well. We got even more heat in my rally MGB than our K Midget (and that's saying something!) thanks to the B's underbody shield being also under the exhaust and trapping the heat. We also only had the bare (well, painted) steel footwell, no mats or anything heavy like that. Andrew was co-driving and, after mile after mile of lovely closed public road special stage on full noise, complained a lot. Being the sensitive father I am, I told him to stop being a wuss. Until the soles of a good pair of trainers of mine melted and stuck to the floor.

So I made up a simple metal shield (no other insulation or anything) and bolted it to the under side of the floor, about 1/2" clearance. Works a treat. Now not even my wife complains. But then she always has cold feet too.
Paul Walbran

Is that part of the macho K-image?

Driving in slippers/sandals?

;o)

Dave
Penwithian

Defo!

If you can't take the heat, stay out of the K-itchen.

A
Anthony Cutler

and wo says it does not get hot with a 1275?!
my exhauste heats up the pasengerfootwel pretty nice

though the escaping heat from the heater works better ;)
Onno Könemann

I hear ya )nno,

Nothing more embarresing then wraping your feet with a thick wad of aluminum foil, Just to drive a 1275

well Okay I never did that, but that was an option I was thinking of at one time...foil booties.

Prop...Im, to Sexy for my feet...Prop
Prop

I have a header on a 1500 too. My problem is that it gets the carb too hot. Runs rough, and nasty stuff comes out the exhaust.

I'm thinking about a two-part response. First, crafting a little aluminium heat shield to go between the header and the carb, perhaps extending forward enough to draw the cool air from the grill to the intake.

Part two is cutting louvres in the hood to allow engine compartment heat to escape.

--john
jf Falconer

This thread was discussed between 23/07/2009 and 27/07/2009

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