View single post by Mark Rosenbaum
 Posted: 04-21-2005 01:50 am
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Mark Rosenbaum



Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
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 I did some casual measurement-free tests of a JH heater not too terribly long ago (details now buried somewhere in the old bulletin board).  The blower fan itself actually moves a respectable amount of air and IMHO isn't all that bad.  The real problem seems to be that the heater core itself is tremendously restrictive to air flow through it.  I'm guessing that the designers wanted to maximize the heat transferred from the core to the air flowing through it and didn't have much concern for how fast that air would move.

There's actually a great deal of room for a heater under the JH dash and I suspect that something from a modern car or pickup could readily be modified to fit.  Also, I think that overall performance would be better if one could recirculate already-heated cabin air, which IIRC is not possible with the JH design.

Another interesting option, possibly only for fresh air, would be to place a small computer fan behind each of the ball vents in the dash.  This might also work for the defroster vents.

Having worked under a JH dash, and having received several root canals, I'd definitely prefer the dental work.   I am much too old, fat, and stiff nowadays to be able to assume the Lotus position, and the dash comes out first the next time I have to do anything much more ambitious than change a turn signal flasher.

Heater boxes do turn up on eBay every six months or so, but you have to watch for them.  They're not exactly the most popular of items, so the price is fairly low.  IIRC, I paid something like US $20-30 for the one I bought, complete with fan.