Seals between inner & outer heater boxes for C2s without A/C

[Richard M.]

Re: Seals between inner & outer heater boxes for C2s without A/C

A tad late with input but the thread below discusses some confusion we had then regarding that gray foam seal(insulator). I'm not sure if changes occurred during the 63-67 era, but a un restored '67 I took apart had that gray seal matching the AIM. I made a colorized diagram then from the AIM page trying to help us all figure it out, as it is definitely confusing.

Ref Thread Here...
https://www.forums.ncrs.org/showthre...ht=1967+heater

My drawing with notes. Note as shown earlier/above by Gary, some repros have holes for the 4 studs. Maybe early C2's had them, then later C2's changed shape and location, unsure. We never nailed it down back then. But I seem to recall all C2 AIMs showed this same profile for the gray inner seal. When I restored all the C2 heaters over the years, I always glued that gray seal to the lip of the inner heater box perimeter as shown in the AIMs. I believe this seal was in place to fill any gaps between the box and foot well carpeted area where it rises up into the box.

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[Gary B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

All,

I did some more digging, and back in December of 2003, Mr Coenen, AKA Doc Rebuild posted this:

“That foam seal slips over the 4 threaded studs, then the steel core support plate with core mounts over the same studs. The two seals that are identical mount on either side of the firewall.

The order is as follows:
Inner box
Foam seal
Metal core plate
Black sponge seal
Firewall
Black Sponge seal
Outer Box.

Some 1963 only use 1 black seal. ??? Don't know why.”

In his first sentence “that foam seal” refers to the large, sideways U shaped seal. That seal in the Doc Rebuild kit has four pre-made holes to slip over the four 1/4-20 studs on the inner heater box. That seals is then held in place by the stamped steel, heater core flange (“core support plate” in Mr. Coenen’s post) which secures the heater core to the inner box with push nuts on the four, 1/4-20 studs. The description in Doc Rebuilds 2003 posting does not describe that same order as in Rich’s colorized sketch.

Two additional comments, the Doc Rebuild U-shaped foam seal is a 2D, die cut, piece of foam. By contrast, the equivalent foam seal in the LIC kit has a 3D cut, with a step in the lip. Which looks exactly like the step in the AIM sketch. And the LIC U-seal has no pre-made holes for the four studs. Which suggests to me that LIC is suggesting to install the U foam as in Rich’s sketch, i.e., not captured by the heater core stamped steel flanges and studs.

Later today, I’ll see if I can find the original U seal from my ‘66.

Gary

[Gary B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

Here are photos of the Doc Rebuild gray seal on the left and the LIC tan seal on the right. Overall view, and view showing 2D vs 3D profiles.

Gary

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[Gary B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

All,

Here’s the original U seal from my ‘66. The view in the first photo shows the side that was directly against the cabin side of the firewall. The seal was still cemented to the firewall at the lower, inboard end. The cement remnants indicate there was cement over a 9” long section along the bottom, starting at the inboard end. So for about 2/3 of the 15” total length along the bottom. There might be a very small hint of cement residue at the upper corner. But no cement anywhere else. And no evidence that the foam seal was captured between the heater box flange and the heater core stamped steel frame. It was clearly not perforated by the four 1/4-20 studs of the inner heater box.

The second photo shows the profile along the lower leg. There is a step cut on both the ID and OD sides, kind of a Z shape. The LIC U seal only has a step on the ID. The Doc Rebuild U seal has no step on either the ID or OD.

The color of the seal is olive brown. But who knows what color that was 55 years ago. In any case, my original U seal just might be sufficiently intact to reuse. It’s mis-shapen and compressed in areas, so I’ll have to see if it can still be properly positioned and will properly seal, and will stay in place while tightening up the Pal nuts on the engine side of the firewall. Seems like a two-person job, which I don’t often have the luxury of.

Gary

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[Timothy B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

Gary,

Would you say that the heater box is installed then the foam seal pushed in place around the box, I believe that's how I did my 63 as it seemed to make the most sense.

[Gary B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

Gary,

Would you say that the heater box is installed then the foam seal pushed in place around the box, I believe that's how I did my 63 as it seemed to make the most sense.

[Timothy B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

Gary,

I don't think the assembly line guys thought that much into it that's why I installed mine after the box was in. The lower portion that is exposed to the inside of the car must accept the top of the carpet.

[Gary B.]

[Timothy B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

Gary,

Yep, very easy to install and move around. Part #3a in the above AIM picture has a note for cement 1.5 oz. insulator to heater. My feeling is it's installed after the box is installed.

[Gary B.]

[Gary B.]

Re: Seals between inner & outer heater boxes for C2s without A/C

I've done 5 boxes, the only way to know is to take it completely apart and rebuild it.

Harry,





Seal F is the one you were talking about. That smaller, thicker seal, as you stated, has to be partially slit and then inserted over the end of the smaller flap door on the small (outlet) end of the inner heater box. That flap door is shown from two opposite sides in my last two photos. As you say, after being partially slit, that seal gets stapled to the small flap door. I agree that to do that requires de-riveting the heater box to gain easy access to the flap door to allow for stamping.





Gary

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[Scott E.]

Re: Seals between inner & outer heater boxes for C2s without A/C

The inner most large door seal can be changed without opening the case by taping the back of ( not the sticky side) to a paint stick, remove the paper backing of the sticky side the carefully feed it through the door opening, close the door then push the rubber pad onto the door and push it down with the stick. Once you untape the stick you can push down on the pad all over to make it adhere.

[Gary B.]

[Scott E.]

Re: Seals between inner & outer heater boxes for C2s without A/C

Yes. I fed the stick with the pad attached through the open door stick first toward the y duct then shut the door and manipulated the stick/pad back over the shut door to the hinge from the end with the Y duct.

[Gary B.]