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Posted by: ConeDodger Nov 19 2009, 12:13 PM

I am hooking up an MSD 6AL to a stock DJet distributor. Which tach adapter? Anyone know the diagram pages for the installation manual that apply? Yes, I have done a search

Posted by: jt914-6 Nov 19 2009, 12:39 PM

Here 'ya go......With my orignal six I used the 8910 tach adaptor....With my 3.0 with factory electronic pickup I'm using the 8920 tach adaptor. You should be a able to use the 8910.....Hope this helps, if not, I'll put up some more info.

Posted by: SirAndy Nov 19 2009, 12:52 PM

I never got that adapter to work with the stock /4 tach. I tried 3 different adapters, none of which produced a signal the /4 tach liked ...

Andy

Posted by: jt914-6 Nov 19 2009, 01:01 PM

I had to run a tach wire from the adaptor to the tach on my 2.0 six (using a Crain Optical) to the tach. For some reason the factory wire didn't work....

Posted by: ConeDodger Nov 19 2009, 01:10 PM

Thanks guys! Got it.

Posted by: jt914-6 Nov 19 2009, 01:17 PM

According to MSD the VDO tach when using the white trigger wire should use the #8910 adaptor, and when using the magnetic trigger connector uses the 8920 adaptor....

Posted by: watsonrx13 Nov 19 2009, 05:08 PM

QUOTE(SirAndy @ Nov 19 2009, 01:52 PM)

I never got that adapter to work with the stock /4 tach. I tried 3 different adapters, none of which produced a signal the /4 tach liked ...

Andy

Posted by: SirAndy Nov 19 2009, 05:15 PM

QUOTE(watsonrx13 @ Nov 19 2009, 03:08 PM)

QUOTE(SirAndy @ Nov 19 2009, 01:52 PM)

I never got that adapter to work with the stock /4 tach. I tried 3 different adapters, none of which produced a signal the /4 tach liked ...

I bought this from Andy and got it to finally work...
Here's a link to http://www.tampabay914.com/7491420060603.html showing how I was able to hook it up.

Posted by: Dave_Darling Nov 19 2009, 11:28 PM

It sounds like some tachs don't even need an adaptor to work with some of the CDI ignitions (like the MSD is). It may be something to do with early vs. late tachs, but I haven't been able to trace a real pattern in the Pelican board posts.

--DD

Posted by: campbellcj Nov 20 2009, 12:12 AM

I think it does have something to do with the vintage/source of the tach. I recently had to install the 8920 adapter for my 70/71 911E tach and magnetic triggered dizzy. Without the adapter, the tach did not see anything that registered a reading at all.

Note that I've heard the speedo shops (NH or PA) can modify the tach to essentially have an internal adapter, but I had already bought the adapter when I learned that.

Gratuitous pic -

Posted by: jcd914 Nov 20 2009, 12:19 AM

Rob and I went the simple route (I subscribe to the KISS method when possible) and hooked the tach wire to the "Tach Output" on the back of the MSD box.

I will admit I cheated and read the instructions for the MSD where is says:
"The MSD Ignition features a Tach Output Terminal on the side of the unit. This terminal provides a trigger signal for tachometers, a shift light or other add-on rpm activated devices. The Tach Output Terminal produces a 12 volt square wave signal with a 20% duty cycle."

Jim

Posted by: ConeDodger Nov 20 2009, 01:24 AM

QUOTE(jcd914 @ Nov 19 2009, 10:19 PM)