<VV> Spyder Thermister

[Frank DuVal]

In a word, NO.

The power that feeds the coil is also the power that feeds the gage, but 
the thermistor side of the gage just goes to the thermistor, not the 
ignition coil. You need a 64 shop manual supplement, figure 8-32 and 
8-33 show this wiring.

The R terminal of the starter should only connect to two things, the + 
ignition coil terminal, and the in harness resistor. The other end of 
the in harness resistor (1.8 or so ohms) connects (through the body 
harness, etc) to the dash wiring, i.e. the other side of the temperature 
gage noted in the first paragraph.

The silicon rectifier is to allow the buzzer to only operate with high 
temperature, not also with low oil pressure, while allowing the lamp to 
light with both low oil pressure and high temperature. This diode is the 
unmarked rectangle on figure 8-32 in the shop manual. About center, two 
inches up from bottom connected between a 20 awg dark green and 20 awg 
dark blue wires.

As to the direct 12 volts to the coil, what does the Igniter literature say?

Does the thermistor change resistance with temperature?

BTW, the buzzer just works with the temperature snap switch (sender) in 
the right head. No connection to the thermistor in the left head, except 
the same 12 volt source feeds both circuits, along with many other 
unrelated circuits.

Frank DuVal

On 2/16/2011 11:35 PM, Smith Family wrote:
> I have a 64 Spyder Coupe that I have had running for 3 years now. Great car, fun to drive, but I have never gotten the cylinder head gauge to work. I installed a new thermister when I rebuilt the engine. I have tested the overtemp buzzer and it works, so I decided to investigate the wiring of the gauge. I found that the positive for the coil is feed by the thermister gauge. The power goes through the gauge then to the thermister plug and on to the positive side of the coil. Is this correct? I have purchased a new engine loom, but the chassis loom is original. I also found that the 'R' terminal on the starter back feeds all the way to the dash and cylinder head temp gauge and then feeds the circuit through a silicon rectifier. This doesn't make any sense as the  power from the 'R' terminal still has to go through the resistance wire in the engine loom. This has me confused. Is the wiring on my car correct? Should I modify the loom to supply a true 12 volts to the coil ( I have
>    an Igniter ignition now). Any help will be appreciated. I am losing sleep over this. Thanks in advance.
>
> Danny D Smith
>