HELP INSTALLING A HEATER BOX

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CFD244

CFD244

"THE NEW OLDSMOBILES ARE IN EARLY THIS YEAR"
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Hi Folks

1971 Demon no AC.
New DMT firewall insulation and shoddy pad.

So, I rebuilt my heater box with the DMT kit. Everything went well.........

I am having trouble installing it now. With the blower motor tightened down to the firewall (all studs protruding equally into the engine bay), and the support rod installed in the cowl plenum, the top of the box is not mating with the cowl plenum. With the new gasket from the kit, it touches on the front portion of the plenum for a distance from about 10 and 2 (clock reference). As you can see by the pics, it has approx 1/2 inch gap at it's widest point.

Am I missing something here, or do I need to pack the gap with extra weatherstripping???

Has anyone had a similar problem?

Thanks FABO

IMG_1812.JPG


IMG_1813.JPG
 
CFD244 said:
Hi Folks

1971 Demon no AC.
New DMT firewall insulation and shoddy pad.

So, I rebuilt my heater box with the DMT kit. Everything went well.........

I am having trouble installing it now. With the blower motor tightened down to the firewall (all studs protruding equally into the engine bay), and the support rod installed in the cowl plenum, the top of the box is not mating with the cowl plenum. With the new gasket from the kit, it touches on the front portion of the plenum for a distance from about 10 and 2 (clock reference). As you can see by the pics, it has approx 1/2 inch gap at it's widest point.

Am I missing something here, or do I need to pack the gap with extra weatherstripping???

Has anyone had a similar problem?

Thanks FABO

View attachment 1716320100

View attachment 1716320101
Click to expand...

Possibly caused by the new firewall insulation pushing the heaterbox back too far from the firewall causing a mismatch to the cowl opening.
Take the box back out, align the cowl duct opening first and tighten the j- bracket in the cowl before tightening the heater motor nuts and the screws in the bracket going around the heater core tubes .
.
 
There is a rod that pulls that in place. 67-72 it hooks on the metal body and fastens under the box with a 5/16 headed screw. 73-76 its inside the door. Its basically a J hook on the top and a 90 with a threaded hole on the bottom. The J hook is usually bent when tightened. When reinstalling bend it back to a 90 and it will pull the box up and bend to its final angle when tightened. Keep the fan bolts lose until after you tighten the J hook
 
I'll give these suggestions a shot tomorrow. The J rod is at the front of the box, so it's pulling the leading edge up to where it belongs......But damn, that's a big gap at the rear to close. Thanks for the pointers fellas :thumbsup:
 
Yep, just wanted to confirm. Like said above I would keep everything loose and "sneak" up on it. Watch the bottom of the heaterbox, you can bust thru it if you're not careful.
CFD244 said:
I'll post one tomorrow. It hooks to the cowl opening above, then down where there is a hole in the heater box where the bolt goes. Pretty much a straight line.
Click to expand...
 
4spdragtop said:
Yep, just wanted to confirm. Like said above I would keep everything loose and "sneak" up on it. Watch the bottom of the heaterbox, you can bust thru it if you're not careful.
Click to expand...
For sure. I had to repair that before starting the rebuild.
 
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