watson

I am just finishing up the heater box on my 65 project and I am looking at the problem of heat inside the car. Before I started the restoration, I had an inline shut-off valve in the heater hose and I did notice that it helped. My problem is that I don't want a valve showing in the engine bay now that everything else has been put back to stock. In looking at the heater box, I see that there is a lot of room between the core and the sides of the box. Has anyone tried using thin heat insulation inside the box to reduce interior heat? I have some firewall heat insulation from another project that is very thin. Just doing some home experiments on the stuff, it seems to really reduce heat transfer. I know that it will not be as good as a shut-off valve, but I thought that it might be worth it while I am inside the box. Am I missing something here or does this sound like a reasonable option?

Thanks,

Doc

66jack

I am interested in what others think also...


Sounds plausible in keeping the heat transfer to the cabin, especially the pass side of car...

The only downside I see, is if the material came loose and cut off air flow to/around heater core...

Scott Marzahl

When i rebuilt my 67 box I sprayed the inside with several coats of lizard skin type heat barrier. Seems to work well.

DansYellow66

You could try some Frost King SA insulation from Home Depot or some EZCool insulation which needs an adhesive applied. Both are probably about 1/8 t0 3/16 inch thick but the EZCool is pretty compressible.

watson

The stuff that I have is about 1/8 thick and it is designed for firewall insulation. It has a sticky back, but I think that I should use some additional contact cement to make sure that it stays in place. I know that the box obviously gets warm inside and that tends to break down adhesive. I guess that there is no real downside, so I think I will go for it. Thanks for the feedback.

Doc

schmibm

Something that may help you is to install a plug or block inside the heater hose near one end. If you wanted some heat, you could drill a small hole in the center to reduce the heater flow but yet still provide some heat. None of this would be permanent or visible from the external. Might be a better option than blocking airflow around the heater core. Just a thought......

watson

I worked on this yesterday and I believe that it will work. I did an unscientific test with my heat gun. I used my temp gun to measure the outside surface temp with the heat gun pointed at the inside of the box. After I glued the insulation around the sides of the box where the core sits, the outside temp was much lower, which was not a big surprise. It may not be a big deal, but the cost was zero and I can't see how it will hurt. I thought about blocking off one hose, but I have read that GM wanted to have flow to the core as a way to increase cooling capacity. I live in coastal California, so I don't see many hot days. I do see some cool evenings and mornings that make a working heater a nice option. The car is still a long way from finished, so I will not have the final result for a while. Thanks as always for the input, this group is a great asset when working on these cars.

Doc