Tach conversion or is there another way?

[rindel]

Hey Guys,

Is there another way to wire up my original tachometer with an electronic ignition (pertronix ignitor III)? The only suggestion that I've seen on other forums is to have my tach converted. I'd rather knot do that since the conversion replaces the guts of the tach. I wouldn't mind buying another original tach and have that converted by I can't seem to find them anywhere. I was hoping that radio shack or some other company made an adapter.

Details on car
69 mach 1 351w
Original distribution with pertronix ignitor III and flamethrower III coil. I ran a 12v wire from ignition switch directly to coil.

[1969_Mach1]

I can understand how you feel. But, the only way I know of to get the factory tach to work is to have it converted (retrofit) with modern day internals. MSD ignition offers a Tach Adapter to get these older tachs to function with their ignition systems. In my experience these adapters don't have a long life (or maybe it was my tach going bad). But, at least its an option to keep an original tach functioning.

It will be almost impossible to find only the tach. Anybody that knows the rarity of these clusters will not part them out and only sell complete clusters regardless of condition.

If you are patient, watch EBay. I have seen a couple of std interior tachs on there but never a deluxe interior tach.

On a brighter side the factory tach probably doesn't have much life remaining. So, it won't be completely detrimental to have it converted.

I was in your position several years ago when my factory tach quit working. Since it wasn't original to my car I sold the complete cluster on EBay and reinstalled the original non-tach cluster. Then added an Autometer tach clamped to the column. The setup is not as clean. But in the end I am glad I no longer have to deal with one of these factory tachs. Plus, I will say the Autometer tach works much much better than that factory tach ever did.

Is that tach cluster original to your car? Back then it was uncommon for tachs to be installed in an auto trans car? The dealer installed hood mounted tachs are reproduced. Just an idea if the tach cluster is not original to your car.

If you decide to convert it I would try this place. http://rccinnovations.com/index.php?show=menu-tach-all

Regards,
Mike

[Dave R.]

I didn't do the work on my '69 but my belief is that my guy just bypassed the pink factory resistor wire and all is OK. Pertronix II with Pertronix coil and factory distributor and the factory tach works just fine. Dave R.

[rindel]

The tach is original to the car and part of the delux cluster. I may get it converted once I get over it. On the flip side, the tach wasn't accurate with the original yellow top coil and points system so might as well.

[1969_Mach1]

Well, its not as difficult to convert if its already inaccurate. Everything I have read is insistent the wiring resistance between the factory tach and the coil be correct for an accurate tach reading. I understand coils with less internal resistance can also affect them.

Dave's tach may work connected directly without any resistor wire. But if it's still an original non-converted tach I be concerned it won't last very long.

Regards,
Mike

[Dave R.]

I just emailed with Pertronix support. "Carl" assured me that there will be no tach damage caused by the Pertronix unit and no modifications are needed. Dave R.

[1969_Mach1]

The concern is without the resistance wire too much current will flow through the step down transformer inside the tachometer and eventually damage it or the movement. I'm sure the Pertronix unit itself won't damage the tach. Am I missing something. . . the factory tach is still connected in series to the positive side of the ignition coil when using a Pertronix system? It's the increased current flowing through that circuit that can damage the tachometer. Did Pertronix explain why it would not possibly damage the tach?

Sorry to sound irritated. But I'll say it again, I just don't like Pertronix. I think their marketing is misleading. I've never used their stuff and don't plan to.

Regards,
Mike

[rindel]

Mike,

I bypassed the tach and tach ballast wire. The ignition 12v has two wires connected to it. One leads to the tach (ballast wire) and from tach, the wire goes to engine bay where I left it open and tucked away. The 2nd wire from ignition 12v (the new one i ran) goes directly to positive side of coil.

The pertronix is working pretty good. I feel a bit more power and response in the car. I installed the pertronix ignitor III with flame thrower III and set the spark plug gaps to .45 since pertronix said I could with the hotter spark. My 0-60 times before the upgrade was around 7.6 seconds. I am now getting 7 seconds flat. give or take +- 2 seconds (then again I also installed trans mounts and u-joints so that may have helped). I know most people would say this is overkill for a mildly modified engine but I am kind of new to this and decided to put in good performance upgrades in the long run. So far I have the electronic ignition, hooker super comp headers, scorpion roller rockers, and 600cfm edelbrock on a stock 351w (not bored). Eventually when I get a bit bored I would like to put in a hotter cam. I really hate to change the intake as I want to keep it mostly stock.

The reason why I asked was because I saw posts about people using tach adapters for current driven tachs. I was wondering if I could use the msd tach adapter as a way to connect tach in parallel somehow without needing msd red box tach output.

[1969_Mach1]

I'm pretty certain the MSD tach adapter will not work with a Pertronix ignition. With MSD, and all other CD (capacitive discharge) type ignition systems, the CD ignition box (1) controls the power to the coil and triggers the coil, and (2) has a Tach output terminal. But, the signal from that terminal doesn't work with older Ford current triggered tachs and I believe some of GM's and Mopars older voltage triggered tachs.

I don't know how similar the tach terminal signal on a CD box is to what you would have at the ignition coil, or if the engine would run. If you don't mind risking the $70 or so for an MSD tach adapter you can take a gamble and try it. For the price of the adapter, you are half way there to having the tach retrofit.

Your motor is not overkill by any means for a street car. In my opinion, Upgrades like intake manifolds don't detract from the cars value. Simply keep any parts you remove. Oh yeah, if you ever replace the intake, don't waste your money on the Edelbrock Performer. The Weiand Stealth, or the Edelbrock Performer RPM are better options for a mild 351W street motor.

Regards,
Mike

[Dave R.]

If everything is working ok, no need to worry.

Too have a Merry Christmas.

Carl Alcocer
Technical Support
PerTronix Inc.
909-273-6007 carl@pertronix.com



-----Original Message-----
From: Dave Rotroff [mailto:drotroff@cinci.rr.com]
Sent: Wednesday, December 2, 2015 11:36 AM
To: Carl
Subject: Re: Product Support Question/Issue

Hell Carl, I don't know. I did not do the install. My restoration guy
followed the instructions that came with the unit and everything seems OK. I
think maybe I allowed some fool with a computer and opinion to cause me some
concern. The pink factory Ford resistor wire was eliminated and replaced per
the instructions. I assume that is the + side of the coil, feeding from the
ignition switch to the coil. But again I did not do the install. After my
email to you guys I thought more about the situation and the more I thought
about it the more I felt like the guy online was talking out of his ass.
Thanks for your prompt reassurance that my tach is not doomed. Merry
Christmas. Dave.

-----Original Message-----
From: Carl
Sent: Wednesday, December 02, 2015 1:41 PM
To: drotroff@cinci.rr.com
Subject: RE: Product Support Question/Issue

Dave,

The Ignitor will not damage the tachs and no modifications required. Does
your tach connect to the negative terminal of the coil or positive terminal?


Carl Alcocer
Technical Support
PerTronix Inc.
909-273-6007 carl@pertronix.com


********** CONTACT INFORMATION ********** Dave Rotroff
Phone: 5132840321
Email: drotroff@cinci.rr.com
Product: Ignitor II
Distributor Manufacturer:
Distributor #:

********** COMMENTS **********
I had the Ignitor II and Flamethrower II installed in my stock '69 Mach 1.
Per the installation instructions the resistance wire was eliminated. All
runs fine. I ran across something in a online forum that has me thinking.
Will this set-up damage my stock Ford tachometer? Someone on the forum seems
to think that the Pertronix, and other similar brands, will damage the
tachometer without installing some type of modification to the tachometer.
Thanks. Dave.


Here is my email string with Pertronix. Read from the bottom up. I'll go with a representative of the manufacturer of the unit. Dave R.