Date: Sun, 17 Oct 1999 18:56:54 -0700
Reply-To: Davidson <wdavidson@THEGRID.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Davidson <wdavidson@THEGRID.NET>
Subject: engine compartment fire alarm
Content-Type: text/plain; charset="iso-8859-1"
Volks,
thought I would share the project that I finished today:
In installed two 194 degree F heat activated switches in the engine
compartment of my 90 Westy Syncro. If the engine compartment gets up to 194
degrees the switches complete a circuit that activates a loud piezo buzzer
that I installed under the dash.
(Please don't tell me about Halon systems.. they are way expensive, illegal
in some start, the fumes are toxic, and the don't work well unless you are
dealing with an enclosed space (the Halon flows down and out the bottom of
the engine compartment).
This competes my three point strategy for the infamous Vanagon engine fires:
1. MOST IMPORTANT.. Prevention. Check those fuel lines to make sure they are
not dried out or cracking or worse seeping fuel. Replace all fuel lines if
any of the above. It may be a good idea to replace the fuel lines at 10
years regardless of how they look.
2. FIRE EXTINGUISHER behind the driver's seat... A fire extinguisher that
has a pressure gauge that confirms it is well charged. (I have two... one
behind the driver's seat and one in its original location behind the
passenger seat.)
3. QUICK RESPONSE: There have been reports of people driving their Vanagon
down the street noticing that the engine is running ruff for some time
before just happening to look into the side mirror to the horror of smoke
and flames! This is the propose of my fire alarm... to get my attention
before flames are flying out of the air intakes.
So the alarm sounds, I pull over to the side of the road, turn off the
ignition (important)(even better to turn off the ignition immediately if you
can coast to the side of the road), open the door, grab the fire
extinguisher behind the driver's seat (don't have to walk around the van to
get the one inside the slider door), open the license plate access, and
empty the extinguisher into the engine compartment.
Parts Used:
1 Piezo Buzzer from Radio Shack... (large one, louder) (about $4)
2 Aqualarm Fire Detectors model 204A--190 degree (#204 is 135 degree)($17
each)
(Aqualarm phone 619-575-4011, or try West Marine 1-800-262-8464 for special
order... Aqualarm model 204--135 degree is West Marine model 105470 but this
is NOT the one you want; I just include it to give them a clue at West
Marine.)
About 30 feet of wire... #16 would work well since the piezo uses way less
than 1 amp.
I pulled power off one off the fuse block under the dash. One 12v power wire
goes into the piezo red wire (don't wire backwards since piezos are one
way), out the piezo black wire, under the van (I installed 6 wires in a
conduit between the engine compartment and the dash last winter), and to the
two detectors at either side of the engine compartment. A ground wire
connects the two detectors to the screw that holds the engine ground to the
sheet metal. That's it. When the temperature goes over 194 degrees F the
switch(s) connect the 12v wire that is routed through the piezo to
ground.... and you get a loud noise.
Note: Last May/June on a trip to Arizona I had the remote sensor of a
digital meat thermometer in the engine compartment... it never got over 160
degrees F... even at 100 degrees outside and the engine running in low gear
along dirt roads or while idling in 100 degree weather. So I believe the 194
degree switch is well suited to the task.
Please note that I make no claims that this set up will actually work to
help you get early warning for fires in your van... I am not a mechanic or a
fire detection expert. This is still experimental for me since it has not
actually detected a fire. If you choose to use the information that I
present here you are on your own and must be responsible for your own
actions.
Bill
90 Westy Syncro