Date: Fri, 25 Oct 2002 08:55:47 -0500
Reply-To: Chris Mills <scmills@TNTECH.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Chris Mills <scmills@TNTECH.EDU>
Subject: Re: Aircooled Heat inline fan?
In-Reply-To: <20021025.001132.756.3.wilden1@juno.com>
Content-type: text/plain; format=flowed; charset=us-ascii
I have heard this: if you put a standard bilge blower in-line with the main
heater tube to boost the air flow you will have two problems.
First is that the fan is plastic and will melt. In fact it states on the
box that they are only rated for 176 degrees or so. As Stan mentioned the
heat is MUCH hotter than that.
Second is that the fan will be sucking on the heaters and pipes. That means
if it is trying to move more air than the boxes and system can supply (fan
is larger than it needs to be) it will suck outside air into the boxes
through the seams or any loose pipes. If there are any exhaust leaks then
exhaust gets sucked into the system and pushed into the cabin. Carbon
Monoxide poisoning.
By pushing air through the system like the standard VW OEM blower, any
leaks in the system will leak air out, and it is impossible to get carbon
monoxide into the heater system if air is leaking OUT unless the fans have
carbon monoxide around them on the input side of the fan which they should
not if your exhaust system is in good shape and if the rubber seals are all
in good shape.
I looked at the systems sold in the VW mags and then took a ride down to my
local marine (boat) store. They sell the EXACT same blower for $18. They
come in 3" and 4" diameters. It is made by Atwood. I took two 3" blowers
off the shelf, paid for them and brought them home.
I plan to disconnect and remove the OEM VW aux blower and replace it with
the two bilge blowers.
On the suggestion of a list member either on the Vanagon list or the Type 2
list I will make one blower a recirculation blower - drawing air from the
bus interior, and the other fan drawing fresh air from above the engine
like the stock system.
I may add some sort of vacuum solenoid to move a flapper valve to switch
the recirculation fan from recirc to fresh.
The system will make good heat if it is tight. My '72 Italian spec Super
Beetle would cook us out of the car even in 20 degree weather with a 1200cc
motor. We would go snow skiing in the mountains west of Rome often. When we
finished skiing I would come back to the car, reach in and pump the gas 3
times to reset the choke, check to the tranny to be sure it was in neutral,
pull the heater levers full on, and turn the key over. It would fire up and
idle fast until the choke began backing off and then idle slower. By the
time we got in the car (changing our wet clothes up front in the trunk) it
was beginning to warm the interior.
The car was always hot in the summer and this was because the heater
flappers leaked. I never disconnected the heater pipe though I should have.
Retrospect is so clear...
I have driven a friend's '78 Westy which was fresh from Arid-zona. It had
the full stock heater system in good shape and the U-pipes had the outer
layer of steel intact (the pipes were originally double layered). It made
so much heat (even in town) my wife actually complained of the heat and
asked me to turn the heat down. Now that the outer layer of steel has
rusted away the heat output is substantially less. IMHO the system needs
more air flow in town to warm the interior. This outer layer could be
replaced by splitting a new steel U pipe obtained from a muffler shop and
welding it on the VW U pipe - using the ridge on the U pipe as a seam to
weld to. Tack welds would be enough.
Also ensure the all the weatherstripping is in good shape. My '78 had a
constant breeze from the cowl vents and leaky door seals. If I could get my
system to make heat, it didn't stay around as it was chased out by the cold
breeze. My van is all new seals, new cowl vent weatherstripping and is
TIGHT. The Jalouise windows are a HUGE air leak. I rebuilt them and with
the addition of new rubber they are tight. A local glass shop had a seal on
hand that is commonly used in storm doors. It slid right in and was correct
for the job. Check it out!
Good luck and warm bus rides to you.
Chris M. <"Busbodger" of "TEAM SLOWPOKE">
Cookeville, Tennessee
ICQ# 5944649
scm9985@tntech.edu
'78 VW Westfalia (67 HP -> that is...67 Hamster Power)
'65 Beetle - Type IV powered
'99 CR-V AWD station wagon
'81 CB900 Custom moto-chickle
2.5 Corvair engines for my Trans-vair Conversion
