BIBA RESTORATIONS
Round-Tail Spider Heater Rebuild

This is the Round-Tail Spider heater. Sort of ungainly isn't it? To be quite honest, this is more of a dismantling, checking all parts, replacing as necessary, cleaning and painting, reassembling rather than a complete rebuild.

A quick summary of how it works: There are two levers - the upper solely for opening the large upper inlet flap. This brings in fresh air.

The lower lever opens the hot water valve and at the same time opens a second flap. Since the heater core does not extend all the way forward. The bottom of this forward flap moves towards the front of the heater about 1" to 1.5". If the exterior plastic flap is open, theoretically, warm air exits into the cockpit.

Two caveats: Biba Restorations really hasn't driven Round-Tails all that much. We fix them, the client drives them. However this one is for BR. Therefore we are not experts in the actual operation of these heaters. The other caveat is that three separate '69 Spider heaters were used in the filming of this extravaganza. The one on the right is a clients which will unfortunately be installed as is. The one below along with the outlet repair photos are BR's. The assembly shots are of another client's since BR's is still somewhat disassembled.

We assume the best way to get heat into the cockpit is by almost completely closing the fresh air flap. Obviously the four L shaped outlets go to the four demister inlets. In fact all of the inlets dump into one continuous enclosed tray. The rather anemic fan / motor, again theoretically, pulls the hot air through the heater cores and eventually into the demister vents in the upper dash panel.

What somewhat mystifies BR is when the secondary flap is opened along with the "hot water being turned on", it doesn't appear to benefit much from the fan. Once up and running, some experimentation will take place to see if a bit more heat can't be coaxed out of the heater.

BR has also been checking into the possibility of installing carbon fiber seat heaters even if located in So. Calif.

    While this is the only time BR has come across a missing vent outlet (we presume it might have been removed to give the passenger / cockpit a bit more heat) this is how we replaced it. Far left photo shows an aluminum ring . There is also one on the inside. Perhaps our demister vent might look familiar. Yes a modified PVC drain pipe elbow and fitting. The end was modified so the air vent hose will fit, the aluminum painted, and the inner and outer PVC pieces glued together so the elbow can still be turned as the other three do.
 
Yes, this is the "other" client's heater. While BR's valve was fine (blow through when open, air goes through; close and no air should get through) this one needed replacing. Molded heater hose to inlet manifold outlet is also new. Motor was cleaned and lubed. Side panels, core support, lever panel, and flaps were sandbalsted (center is too thin to blast). Lever and emergency flasher switch panel were wrinkled painted. Plastic panels were painted with special plastic / vinyl paint. Metal panels were epoxy primered and painted semi gloss. New quality all stainless hose clamps were used.

The original foam used is the soft yellow stuff which disintegrates quickly. BR used .25" foam which should not leave yellow bits on the carpet and should seal considerably more permanently.
 

This should impress those pesky judges, even if the heat ouput doesn't.
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