Electronic tach

[Lester]

Hi all, Haven't been here for quite a while. Getting close to finishing complete ground up do over of my 56 and have changed some things. In an earlier post by mmbuffny, he stated electronic tachs are available that fit the housing. I would like some specifics. The housing measures 3 5/16" so I was thinking maybe a SUN PRO 3 3/8" might work if I were to trim the edge so it would fit the face bezel. Any ideas. Anyone tried this before.

To all, thanks a bunch,
Les

[mmbuffny]

Hi, its mmbuffny. I was doing some research and the part that matches almost perfectly to the stock tach is part number ATM 3788 avail from Summit racing for 159.00 /free shipping. From my research, you can reuse your stock tach black background and use that in place of the aftermarket tach background which is white. The nice part about this tack is that the numbers all line up. So thats all you have to do is remove the new tachs background and pop in original background. I have not done this yet as I am still working on the frame but I am always thinking ahead. Let me know what you come up with and if you end up doing the project. Mike

[paul2748]

CASCO sells a combination electric tach and vacuum gauge that fits in the place of the stock tach.

[Lester]

Thanks mmbuffny, I will check that out. I got a new Sun Pro cheap off ebay and it fits in the original tach cup if I redrill the mounting holes and use a couple of 3/4" standoff's. The look is nothing like original but it works. I am going to look at the one from Summitt and see how it might look.

Thanks,
Les

[Lester]

mmbuffny,
I looked at the tach from Summitt and I am not sure of the space between the face mounting holes and I asked Summitt for that measurement. I also asked if it would work on a V8 gas engine (theirs is for a diesel). We'll see. 0-5k looks good, better than 0-8k for looks and maybe could use original lens and needle, that would be cool.

Thanks,
Les

[Lester]

mmbuffny,
Well now ya got me goin'. Did some more research on it and the 3788 tach won't work with gas engine, (it might but it triggers off the alternator not the coil) BUT .. the 2697 will and it is $124 at AMAZON. I think (oh,oh) that if you were to cut a piece of 18ga. 1/2" wide by 2 1/2" long, you could adapt the Autometer movement to the original Ford face. It would only be a matter of attaching the movement to the original cup at the back. I am going to see if I can find one on ebay cheaper to experiment with. Hummm.

Les

[CSavaglio]

What's wrong with the original tach? I'd be hesitant before you start tearing the old one apart, drilling the cup and using it for parts since t-bird tachs are worth money.

There's an old school shop here in Colorado that repairs speedometers, tachs, generators, alternators, etc. I've been going there for 10+ years and he's done work on every old car I've owned. He's rebuilding my '48 Buick's speedo right now and he rebuilt/calibrated my T-bird's original a few years ago.

He's a vendor on the HAMB and does lots of work for out of state customers. There may be someone in your area to work on it or you can talk to him.

Chris

[Lester]

Chris,
Using a 57 dizzy with no tach drive in a 56. I could leave the original tach in as a dummy but would like to have a working tach. Am looking at the new Auto Meter tach which is 0-5,000 rpm and I think I can use it in the original tach cup.

Les

[Lester]

Mmbuffny, look at the "ApexMeter" 0-5k w/ hour meter. If you change the face you could cover the hour meter. Only $60 inc. shipping. Might be worth experimenting with. It is on Ebay.

Les

[CSavaglio]

Right on....I went nuts when I did my top end upgrade trying to find a 57+ tach drive...only T-birds, Turnpike Cruisers, and possibly a couple others had them. The couple I found didn't even look rebuildable and they were over a grand. A search for an old dual point aftermarket distributor turned up nothing too.

I ended up getting the Mallory tachdrive, but, because I'm running 6v pos ground, I couldn't use the included ignition module. I ended up having Pertronix, who makes an ignitor for the Mallory and a 6v pos ground one for the stock distributor, make a custom one for me combing the 6v electronics with the magnet ring and plate for the Mallory. I painted the red Mallory cap black to camo it a little and not draw the eye, but it's obviously a billet distributor and not the cast factory style.

[Lester]

Chris,
Could you have converted to 12V? I don't know if you could just convert the ignition system and leave the rest 6V. 57 Ford dizzies are somewhat plentiful and relatively inexpensive, that is why I went that way. I think I might order the tach from Apexmeter and play with it. If I can put it in the original can I think it will look a lot better than the SunPro I put in. If I can do what I am thinking then it will look original and be functional too. The 57 manifold and dizzy work great and I used the original air cleaner base with the SS top and a K&N filter. Looks original and runs a lot better. It is a given that some things won't be right like no tach cable. I'd like to find a used one cheap and remove the drive cable from the sheath and put the coil pick-up wire inside the sheath just for looks.

Les

[Soonersace]

Here is another question. I have upgraded to the Mallory Distributor. When I reattached the tach cable it got ripped apart and will not work. I thought my tach was old so I sent it in to get rebuilt I still have the same problem.

If I replace the tach cable it lasts about 20 miles before the cable shreds at the distributor.

Ive replaced it 3x to the same result. fortunately the cable is only 25 bucks.


Any ideas or suggestions?

[Joe Johnston]

Is your cable housing routed correctly as per the sketch in the Electrical Manual? It may be bent to sharply causing a bind.

[CSavaglio]

It's a source of pride for me to keep the car with it's proper 6V pos ground system and besides that, I had quite a bit invested in 6V specific equipment. As I've posted before, I think most people end up converting to 12V as a bandaid solution to other issues since the higher voltage overcomes things like iffy switches, poor tuning for starting, worn out headlights or the wrong voltage headlights, etc. There's not really a way to convert just the distributor to 12V without replacing the battery and generator/alternator. If you leave everything else 6V, it'd require potentially unreliable voltage regulators. They used to be really, really bad about failing, but I think newer ones are far better, so that's not as much an issue.

As far as your cable goes, did you use the correct type? The Mallory uses a different end than the original. I assume you are since I don't think there's a way to attach the original style to the Mallory.

This is the one you want, if it's not what you've been getting.

http://www.larrystbird.com/product/tach ... stributor/

Outside of that, check the routing as mentioned, and check to make sure the tach spins freely by hand, but without the cable and with. There shouldn't be much drag on it and you can make the tach read RPM by just spinning it with your fingers from behind. If it binds without the cable, it needs rebuilding. If it binds with, the cable is the issue.

[Lester]

Soonersace,
What are you doing with the messed up tach cables? I could use one as mentioned above to "camoflage" my tach wire. Respond here or PM me.

Thanks,
Lester