Has anyone ever gotten the 4 cyl. tach to work with an MSD6al or the Mallory? Even with the "Tach Adaptor" from MSD I have never been able to make it work. On my 6 I just had the Tach rebuilt and modified for use with MSD. But I've been asked to help instal two others for friends and never seen a stock tack work after MSD.

Anyone???

Hmmm... that is strange. I use the 6AL with the adapter and it works really well - never an issue at all. Have you started the install on the other car? I am wondering if you had a bad adapter or tach in the previous attempt. I did have a tach go dead several years ago - litterally just stopped working. Replaced it with a 35.00 used one and have had no problems since.

I am taking the plunge like you did however and having the tach redone to be "plug and play" for my conversion (it is also an excuse to get the 10k rpm guage face....)

I have a Mallory CDI that I works fine with my stock 4 cylinder tachometer.

Does your tac look like this on the back?

Click to view attachment

More information on the Mallory Hifire 6A installation.

If you go here: http://www.jegs.com/InstallationInstructio...0/650-6852M.pdf and you can secure the installation instructions.

You'll need to choose which set up is the right one for your situation, i.e., like in my case installing with a Malory Unitlite or Magnetic Breakerless Distributor.

Yep same tach. I just swapped another tach and got the same results, Nothing....
Guess I should check wire for signal.
This install is the Mallory6al and a Mallory Unilite Dizzy. Mallory references the MSD adaptor part number in the manual for VDO tachs. When I plug in the adaptor I get a tach bump when I start to crank the engine but that is it.
Going back out and getting the Volt meter...

Randall, Thanks. I have the manuals etc., it is all hooked up and the running. Just no Tach. I put the MSD Adaptor inline with Yellow (tach) wire from the Mallory. and the switched on power for the box. The engine still runs fine but still no Tach.
I used a Volt meter and got 12v and 1.75-1.85 bounce on the signal wire with engine running... maybe I'll just try another tach. (got 4 of them in a box somewhere )

Any other Ideas?


PS - I do remember my Tach working when I did my six conversion, however it was a 4 cyl. tack and I was getting 1.5 x the signal....

I don't have a solution for you, but I did want to mention that we've seen this before in pretty much all combinations. Some were able to just plug the MSD tach output into their tach signal wire and have it work, some required the adaptor to make it work, and some didn't even work with that.

--DD

Do you have the correct tach adaptor ? there are two ya know; a flattish one and one with a hump ( don't remember the part numbers) . Mine works great with the Mallory Unilite and humpish tach adaptor

OK - So swapped in two other tachs. One early and one late. The late Tach from a '74-75 works with no adaptor! Niether of the early ones worked at all...
Solution - Lose the Silver Button Centers - Oh well.

Yes, I'm running the MSD 6A and Unilite with no adapter, and my tach works fine.
I don't have the wiring diagram in front of me, but IIRC there's an old thread or two on here about "how to".
Then again, like Dave said

Mike

Do a search here and on the bird board and you'll find a lot of topics on aftermarket CD ignitions and the stock tachometer.

While you may have found a tach that works off the output from the CD ignition, it may not give you the correct reading.

914 tachs take a high voltage signal from the coil, MSD tach signal is low voltage.

Remove the tach signal wire from the coil and hook it to the MSD yellow TACH wire, then modify your stock tach to trigger off of low voltage by placing a jumper across the input signal resistor. While you have your tach apart add the proper capacitor across the coil windings to cut out the tach bounciness. Just be carefull with the trim rings, those things are a pain.

IIRC, JCD914 took the signal directly off of the MSD6AL tach plug that comes off of one end of the box. It worked fine...

That one.
Aaron's thread from years back was the one I referenced when I installed my MSD.
Mike

Mike,

See: http://www.914club.com/bbs2/index.php?show...368&hl=coil

Also, North Hollywood Speedometer can install a small adapter on the back of your Tach to convert the signal.