Monday, February 20, 2012

Monitoring Westly's Vital Signs

Vintage Volkswagens typically had a speedometer and a fuel level gauge. Within the speedometer face were a warning light for low oil pressure and generator malfunction.  Some models added a clock.  Millions of people happily drove multiple millions of miles with this minimum amount of information about their vehicle.  When the water cooled engines came along, a water temp gauge was added.  Later, depending on the model they might have a tachometer, volt meter, oil pressure , turbo boost, trip computer, and so on.

Westly originally came with a speedometer that topped at 85 and a large analog clock (surprisingly accurate) with a water temperature gauge inset at 12 o'clock and fuel level at 6 o'clock.  The water temperature gauge has a red LED in the center which flashes if the engine overheats (the '83 and later Vanagons which have a water cooled gas engine also activate this light if the coolant level is low).  In between the two gauge faces are five LEDs which show turn signals on (one light covers both directions), high beams on, low oil pressure, battery discharge, and a yellow one for the glow plug timer (to start the diesel you turn the key and wait a few seconds until the yellow light goes off before cranking it over. The glow plugs literary glow red hot in the combustion chamber to start the fuel ignition process).

I like to have a little more information than that so I soon began planning to add additional gauges.  I consulted with the Vanagon online community to see the various ways others had accomplished this.  I wanted to try to keep the gauges together in a cluster rather than in individual pods scattered about the dash.  It didn't turn out quite this way, but close.

At I found a three-gauge pod (GS-WRXD) made to replace the clock in a Subaru Impreza.  The shape was similar to the Vanagon instrument cluster and the angle of the dash was close.  The price was reasonable so I ordered one.
Meanwhile, I began collecting gauges.  I've always liked the clean look of the VDO Cockpit line and they are similar in style to the stock Vanagon instruments. I had a temperature gauge left over from a previous project so I began there. There was an oil pressure gauge for sale by a member of the Vanagon online forum.  I had a small tachometer, but it would work only on a gas engine ignition so I found the diesel version at and also picked up a volmeter, hourmeter (every real industrial diesel has one) and sending units for the temp gauge.  A hundred feet or so of wire was needed (it's a long way from the engine to the dashboard), a plastic loom to protect it on it's way, and miscellaneous connectors and zip ties.

When the pod arrived, I saw that it needed to be modified to fit just right.  I intended to mount the pod directly over the ash tray and speaker grill in the middle of the dash.  There was no longer a speaker there, and I used the ashtray only for collecting used earplugs from my job at the airport.  I pulled out the ashtray so I could run the wiring loom through the hole.  After determining the angle I cut a couple of pieces of galvanized trim, and riveted them onto the pod.  

Bondo was used to fill out the shape and cover the rivets.  After a lot of sanding, shaping and sneezing, the fit was just right.  I covered it with black hammer spray paint and sprayed the stock instrument cover as well to match.  By the way, a small dab of grease on the metal tabs that hold the instrument cover on make it much easier to remove and replace, and the plastic tabs are less likely to break (common Vanagon problem) when you don't have to mess with it so much.   

The temperature, pressure and volt gauges were mounted into the pod.  I added a small switch on the temp side so I could choose between oil and water temperature.  On the volt side, I added a switch to choose between starting and "house" battery (not yet installed, but will be for running accessories while camping so the starting battery doesn't get run down).  Above the switches I added a red and a green LED.

Wiring the pod.  The velcro strips around the edge hold
it in place on the dash
I made up a wiring loom using five 18ga wires, marked at each end with a number.  I ran the loom from the engine compartment, alongside the original VW wire bundle, up beside the radiator and into the body under the dash through a previously unused grommet-ed hole.
Installing the wiring loom
Inside the engine compartment, I began installing the sending units, connecting and tying the wires up and out of the way.
Water temp sending unit at the outlet to radiator
Oil pressure sending unit on the back of the block
One side for the gauge, other side for the warning light
The lower connection is for the stock water temp gauge
Oil temp sending unit on the oil filter mount 
The loom snakes through the engine compartment
terminating at the alternator
I made all the electrical connections and started it up.  The alternator-driven tach doesn't read until the first time the engine reaches about 1500 rpm, then the Alt light goes out and the tach activates.  After that it's ok.   It has some dip switches and a small potentiometer for fine tuning so it takes a little fiddling with to get it spot on.  I wired the red LED to the glow plug circuit.  This will stay lit as long as the glow plug circuit is active, which depends on the engine temp and the ambient air temp, usually about 1-3 minutes.  I use it to time my warm up - when the lamp goes out, it's time to drive.  The green LED I wired into the auxiliary cooling fan circuit which will be described in more detail in a later post.

The hour meter is down below the dash as
readings are needed only for maintenance records

The gauge pod in place
Oil/Water Temp, Oil Pressure, Volts
Gauge installation completed
2" Tachometer is centered between speedometer and clock
for more direct line of sight
Now that I could keep a wary eye on Westly's vital signs, I was stunned by what I learned.

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