I would not expect 321 to crack and fail in thermal  cycles

below 1600

degrees.  I don't know how
hot the cool tube will become but if it does not reach 1600

degrees then no problem, ever.    Jerry

Jerry, my two cents worth is this- why risk it? I thought I'd just
use
a heater core since we are using a liquid cooled engine, but then I
saw that someone (don't remember who) just took air from the back
side
of the radiator. This way, you don't  have the worries of an
exhaust
leak, and don't have the worries of the weight and potential
failures
of a heater core.

Brian Trubee

     Matt Prather wrote:

I don't think you get enough temperature rise by just piping air off
the back side of the radiator - especially in the winter when you
need
the heater the most and the input air is the coldest.  You could put
a winterization kit of sorts on it.  Feed cabin air via scat tube up
to
a duct mounted on the corner of the radiator, and then heated air
from
the same corner of the radiator back to the cabin.

It still seems slicker to mount a small heater core in the cabin.
Maybe
slightly heavier, though.

Regards,

Matt-

Those are good points. The reasons that I decided to try taking hot
air off the back of the radiator  are these-

Elimination of the weight of a heater core.

elimination of potential failures of two heater core hoses, and at
least four fittings.

Also, I'm using a cowl flap, so I shoud be able to control the
coolant temperature. with the cowl flap, I should be able to almost
completely close off the exit air from the cooling system if I
wanted to.  If this scheme doesn't provide me with enough heat, I've
got a heater core sitting on the shelf, it would be no real problem
to install it later.

Brian Trubee

Rv-4, hoping to be done by next summer.

You guys need to have a look at the extremely neat cabin heaters built
by Ed Klepeis. for use with any water cooled engine.  If I don't use
direct hot air from the cool tube then I will be sending Ed a check.
Ed,  If  you read this, how about posting a picture of your cabin
heater and giving us the specifications.   Jerry

 
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