Join Date: Mar 2002
Location: Austin, TX, USA
Re: electrical questions on 66 nova!!
With trunk mounted batteries you have to be very judicious about keeping the electrical connections tight and clean. Most starters start to loose their umph at 8 volts. Also, the starter can draw nearly 100 Amps during a crank. If the battery provides a steady 12volts during crank (unlikely), you've got 4 volts of "head-room" to work with on the battery voltage. At 100 amps, it would take only 4V/100A = 0.04 Ohms of resistance to make the starter stop working and that ain't much. In reality that 12volt battery probably drops to 10 volts during a cranking in which case 0.02 Ohms of resistance is all that it takes to stop cranking.
It's hard to say what's going on in your case. I'd get rid of the ammeter - especially if it is an in-line type. Volt meters give you a better visual on electrical system health IMHO and don't present a resistive load to the electrical system.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI