MSD Ignition box & AutoMeter Tach Question
11-26-16, 02:00 PM
#1
Junior Member
Thread Starter
MSD Ignition box & AutoMeter Tach Question
Hi Guys!
I am using an MSD 6A Ignition box on my 12A motor (see photo). The MSD ignition box direct fires 1 coil per lower plug and uses a 3rd coil to fire the upper plugs via the distributer as normal (although I moved the upper plug wires to the lower post on the distributer). I followed the directions for this MSD setup that I found on this and other sites and left the MSD box setup for an 8 cylinder motor (did not cut the 8 cylinder wire loop coming out of the MSD box). This setup works fantabulous!!! I can highly recommend it to anyone out there running a first gen motor. If anyone is interested I can help with any questions you might have. Mine motor also has the RacingBeat intake, header, and Holley carb.
I hooked up a new Autometer tach to the MSD ignition box per the instructions. I left the Autometer setup for an 8 cylinder motor just like the MSD box. The tach that was in the car originally did not work so I tuned the motor and choke using a vacuum gauge and basic ear and feel tuning. It starts perfect, idles and warms perfect, comes off the choke perfect, and runs through all gears fantastic.
But!... here is my question, now that I have the tach hooked up it seems like it is reading too low. Seems like the tach is showing maybe half of the rpms the motor is actually turning but maybe it is reading correctly and I just did not realize before the rpms I was running. I thought I was spinning more like 6,000 at times but looks like it is more like 3,000 based upon the tach.
I could have hooked the new AutoMeter tach directly to the coil that fires the top plugs via the distributer and I should have tried that as a baseline but I hooked it up to the MSD ignition box in total blind over-confidence and it will be a pain to pull that dash back off the front of this little Triumph to get to the tach wiring and ignition box.
So, anybody have any experience with this type of setup? Any advice greatly appreciated as always!
Thanks!
Bill
I am using an MSD 6A Ignition box on my 12A motor (see photo). The MSD ignition box direct fires 1 coil per lower plug and uses a 3rd coil to fire the upper plugs via the distributer as normal (although I moved the upper plug wires to the lower post on the distributer). I followed the directions for this MSD setup that I found on this and other sites and left the MSD box setup for an 8 cylinder motor (did not cut the 8 cylinder wire loop coming out of the MSD box). This setup works fantabulous!!! I can highly recommend it to anyone out there running a first gen motor. If anyone is interested I can help with any questions you might have. Mine motor also has the RacingBeat intake, header, and Holley carb.
I hooked up a new Autometer tach to the MSD ignition box per the instructions. I left the Autometer setup for an 8 cylinder motor just like the MSD box. The tach that was in the car originally did not work so I tuned the motor and choke using a vacuum gauge and basic ear and feel tuning. It starts perfect, idles and warms perfect, comes off the choke perfect, and runs through all gears fantastic.
But!... here is my question, now that I have the tach hooked up it seems like it is reading too low. Seems like the tach is showing maybe half of the rpms the motor is actually turning but maybe it is reading correctly and I just did not realize before the rpms I was running. I thought I was spinning more like 6,000 at times but looks like it is more like 3,000 based upon the tach.
I could have hooked the new AutoMeter tach directly to the coil that fires the top plugs via the distributer and I should have tried that as a baseline but I hooked it up to the MSD ignition box in total blind over-confidence and it will be a pain to pull that dash back off the front of this little Triumph to get to the tach wiring and ignition box.
So, anybody have any experience with this type of setup? Any advice greatly appreciated as always!
Thanks!
Bill
11-26-16, 07:43 PM
#2
I'd attach the tac wire to the trailing coil (the one that fires the distributer) just as Mazda did. Obviously, this is NOT a factory situation, but maybe there is a reason for it.
I imagine you should be able to set up the tac as you would on a Mazda product if you connect it to the trailing coil.
I imagine you should be able to set up the tac as you would on a Mazda product if you connect it to the trailing coil.