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MG MGA - Hotter than hades

A separate question.

I'm sure this is endemic to MGA's and I'm sure someone has already come up with a solution.

The issue is that the cockpit gets hotter than hades, right along the drive train tunnel next to the gas pedal. I swear I melted the hair on my right leg.

In my reading I've seen that you can put carpet insulation under the carpet along the tunnel. Also there is some sort of insulation blanket that can go on heater shelf and the upper bulkhead. This should reduce the problem somewhat.

The question I have is this. Can you put a stop cock on the water supply to the heater core to stop the heat from working and allow only fresh air flow into the cockpit.

Thanks,

Tysen
Tysen

The heater and fan have separate controls, so you can run the fan without the heater. The problem is that many of the replacement heater valves do not close off the water flow completely. There are several posts in the archives about how to fix this.
Jeff Schultz

Also, Tysen, take a long hard look at the gap between the underside of the cowl sheetmetal and the top of the firewall. My MGA was missing the packing (OE was a horsehair felt stuff) between them and HOT air from the engine compartment came in by the barrel.

As for a good insulation, take a look at your local hardware stores for a hot water heater blanket material with a mylar foil and net reenforcement on one side and multicolored "felt" of some sort for the body of it. It is about 3/8"-1/2" thick and works well, foil side down. You could also buy the same stuff and pay more and shipping from JC Whitless, billed there as "Space Age" insulation. There are other insulation materials folks have found at their local hardware stores, and, as said, there is plenty in the archives on the subject.

Just know that the most effective job of insulating is the one which covers the whole firewall (even the horizontal sections) and trans tunnel, not just up to the height of the carpeting or right next to your foot. Good luck!
Bob Muenchausen

I used the coupe insulation under the dash, put in all new rubber grommets on the heater shelf, used water heater insulation on tunnel and floors. Put your car in the garage and put a light in the engine compartment and close your garage door and have only the light in the engine on. Look for places where light comes thru as this is where heat will come thru. I now do NOT have a heating problem. I also used a heat shield on the exhust pipe to help elimate heat on the floor board below the driver on LHD cars
JEFF BECKER

Bob comes up with a good point about sealing the tunneling in the firewall area. I have gone to a great deal of effort plugging every unused drilled hole in the firewall and ensuring all cables cable/pipe ways are tightly grommetted. I have also rammed packing into the gaps between the firewall and the outer skin (forward of the windscreen posts). However, during my recent escapade in France I was aware of a hot draught around my legs and I am now sure it is migrating from the tunneling join. I also get hot air coming out of my home made leather gear stick gaiter (5-speed box modification - the original rubber gaiter kept pulling the gear stick into neutral whenever I took my foot off the throttle!)

But yes Tysen, the tunneling does get very hot. You will see dozens of threads on this BBS about engine compartment cooling. The MGA has great trouble getting rid of its hot air, so much of the metal work in that area get red hot, the tunneling included.

Steve
Steve Gyles

Tysen
What I do to fix my heater problem is remove the two water lines at the heater and join them together. That way all you get coming into the cockpit is outside air.
Kris
Kris Sorensen

I have yet to be too cold in my MGA so I decided this year that the heater was an extra I could do without. Rather than just remove it I removed the heater hoses and blocked off the water outlet at the elbow and replaced the heater valve with a blanking plate. I then disassembled the Smiths Heater Box and removed the heater core and plugged the heater hose holes in the box with grommets. I left the fan and motor in place and reassembled the unit. The look is stock but when the cockpit heats up I just flip the fan on and I get cool outside air into the footwell thru the heater box which now serves only as a duct to collect the air and send it into the cockpit. Air flows freely without being obstructed by the heater core. The air can be blocked if desired by turning the fan off and closing the air damper. So far so good !!
Michael Hosier

This thread was discussed between 26/06/2005 and 28/06/2005

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