Elvira : Rebuilding the 36hp, episode 10 : Heater Boxes

I've never had any heating in this ride, which kinda limits its usage in winter (yes, even on the French Riviera!).. Even though I've owned it for over 25 years! It's high time I do something about it!

Heater boxes

I initially only had J-Tubes on my engine ; so I started by sourcing a pair of used heater boxes. A bit of rust, a couple of dents and holes, a locked mechanism and a missing lever... But nothing patience, WD40 and a MIG can't fix. So I start by thoroughly cleaning, followed by sandblasting all the parts. I protect with a bit of masking tape the part of the mechanism that can't be taken apart easily (as its welded in place), to avoid messing with it while sandblasting...

One of the mechanisms is seized by rust (articulated lever) ; WD40 doesn't help, and the bearing finally ripped off as I was trying to free the lever. I finally managed to persuade it to move after clamping it in the vise, so I plug-welded it back on. Done.
On the other side, the mechanism was not seized, but was missing the lever actionnating it. Using a piece of masking tape, I copy the shape of the one present on the other box. Two saw cuts, some filing and drilling two holes, I have a pretty good copy ready to plug weld in place. All parts finally get a couple of coats of rattle-can Rustoleum hi-temp paint (supposed to handle up to 650°C/1200°F, but I won't hold my breath). All the hardware gets bead blasted, and it's ready for reassembly.

Engine tins

For the whole system to work properly, and for the heated air to be actually forced into the passenger compartment, it requires the under engine tins to be present with their moving flap to redirect the airflow. I did not have those tins on my original engine, and they are getting harder to find (and never built as reproductions). But with some patience, regularly checking online ads, and some bucks, I finally found a pair.
The ones I got were in an ok state, with just a little tab broken on one of the moving flaps. Thorough clean up with naphtha and brake cleaning fluid, then bead blasting to get rid of the flaking paint. And since those are below engine tins,exposed to road gravels, I brush two coats of Hammerite, as it will protect them better than any body paint. Here you can see the left on in its original state, and the right one after full treatment : I can then focus on fixing the broken tab on the other heater box : only took some MIG persuasion to tackle it. Bead blasting again it is, and a lick of paint again : And... Taaadaaaaa!!
While I was at it, I also changed the flaps control cable, the little rubber boots back where the cable gets out of the chassis, and the fittings on the boxes levers ; next I'll put all this back in the car, and make sure the flaps actually move as expected!
But this will have to wait until the next episode!