My 66 uses an MSD Ready to Run distributor (no box). I run a stock small cap to keep it looking original. My coil started to leak oil so I bought a new black MSD Blaster 2 coil. Once installed my vintage Sun SST 802 R tach would read way too high at idle. I switched it to a stock type coil and the tach works perfect again. I will say spark is greatly improved with the MSD coil. Seems to start a bit better. Not sure if it runs any different. The primary resistance is much lower on the MSD coil, .6 vs 1.8 ohms. Anyone every encountered this and know if a fix for the tach issue?
I dont think 1 ohm in series with the tach will help. Im thinking the lower resistance of the MsD coil causes less voltage drop across the coil. So, the tach gets a higher voltage wave at the same frequency. Possibly something that matches the input resistance of the tach to create a voltage divider. Ive heard 10k ohm, I tried it with no luck. Same problem.
Maybe i should try a potentiometer. I could increase or decrease it to find a correct ohmic value?
Ill try a 1 ohm and post the result. 1 ohm wont have any drop across it in series with the tach, but Ill check it out.
I just measured the input resistance of the tach. Its 250k ohms so its no wonder the 10k ohm resistor did nothing to make it better. Ill try a 50k and a 100k ohm on Tuesday.
I put the MSD coil back in and started playing with resistors in series with the Sun Tach. Ended up that a 33k ohm resistor did the trick. Just thought id close the door on this one in case someone else has the same issue
