3 replies to this topic

[hanra]

Ive got a mate with a MSD 6A fitted and his stock tacho is not working correctly. Im yet to take a look at the install so Im not sure how its been connected. If its using the the Tach Output terminal on the MSD or not... 

 

He has ordered a Tach Adaptor which will arrive in a few weeks. 

 

Has there been any definitive success with MSD boxs and stock tacho's? Is the Tach Adaptor the answer? 

[jd lj]

It goes something like this....
The stock tacho reads a coarse signal but the MSD puts out a fine signal.

My local instrument repair guy changed something within the tacho to make it read off the MSD signal with no tach adapter required. Other's may have more specific technical information about the different signals but that's the basic idea.

[76lxhatch]

I have a 6A and have tried the tach adapter and it never made any difference, reads the same with and without. Its connected to the output terminal on the MSD box, and reads just as well as connected to the coil without running the MSD (which is to say, the tach reads low like all original Holden units that have never had any attention).

[hanra]

Yeah I might have to whip his cluster out and bench run it on a function generator to confirm it’s ops. I have a feeling he had sent it to an instrument shop for bench test during his resto.