MSD 8920 Tach Adapter without MSD 6AL

John,

The MSD tach adapter takes a digital signal and converts it to an analog signal.

The Veglia tach requires an analog signal.  If you have a Veglia tach, it can be connected directly to the negative coil terminal without the use of a tach adapter.  

John

I have an 8350 ready to run and a MSD 6A box without a tach adapter.

...just curious, does the "Multiple spark" confuse the tach? I have my doubts about whether the multiple spark does anything, and the good news that at higher RPMs (maybe 3krpm) it drops back to a single spark. Its possible that the energy in the spark only 'registers' once, but might connection at the coil inflate especially the idle RPM?

(its been 20+ years since I've read up on this, but the conditions to really get a spark and propagation of flame are really pretty narrow and there are unlikely to be second chances...).

Thank you for all the information gentlemen.  I thought I had read something about the blaster coil and msd distributor burning out the Veglia tach if connected direct.

I should have done more research before buying the adapter.  I guess there will be a NIB adapter on EBAY soon

Thanks,

John

You can use the tach adapter with the 8350 distributor. Use the grey wire from the distributor to connect to the adapter.

See diagram attached.

There should be no worry about connecting to the Veglia tach, it doesn't make any sense that the MSD would damage what is a rather simple resistor/capacitor input on that and then just an old fashioned transistor...). The only worry should be about low RPM accuracy (if indeed the coil is sending multiple triggers, it may appear as higher RPM..)

.

Pantera-Electronics makes a Tach Adapter that applies to this situation. Go visit his site.