Neil, I came up against the same problem you're having when I did my air to
water conversion. I couldn't find any practical way to recycle the air
unfortunately. If you do, pass the info along. I would, however recommend
you block off the two hoses coming out the sides of the heater box. These
are fresh air hoses that go to the far left and right dash vents and don't
heat when the heater is on. Maybe the vent flaps close off the air flow
enough though. With that done, I've found the heater works plenty well here
in Utah during the winter.

Ryan
'82 Camper Van 'Beethoven'

Date:    Wed, 21 Mar 2007 13:37:26 -0800
From:    neil <musomuso@GMAIL.COM>
Subject: Mod. Fresh air box to recycle cabin air? (did some searching in
arch.)

Hi all.

Am rebuilding fresh air box and will install heater core as I will convert
to a water cooled engine.

I understand how the box works but.....

Assuming box rebuild and engine conversion done properly;

will the heater properly heat cabin in really cold weather?

(There isn't going to be a rear heater)

If not, is there a way to mod box to recyle the cabin air?

Obviously recycling air from cabin would at least make initial heating
process more efficient.

One idea I had in that regard.

Block off fresh air intake, (or make flap to control fresh air intake at ram
outside.Difficult I know....), remove fresh air ram flaps, make/install a
piece underneath area below flap(s) to block air from being "pulled" from
area of box pressurized by fan, so air from cabin could be drawn from side
fresh air vents.The drawback would be no more fresh air from fresh blown
from air vent at ends of dash.

Has anyone done this? If I'm totally off base, please educate me!

Any thoughts or success stories in this regard are welcome.

And for you air cooled people considering upgrading to water cooled, I can
provide pics of box showing how/why heater core can be installed. Have not
installed heater core yet. (Am waiting for parts!) but can show where box is
cut for heater core nipples.

--
Neil Nicholson. 1981 Air Cooled Westfalia.

http://web.mac.com/tubaneil