after market tach?

wildman7798

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will any old afrtermarket tach read accurately or do i need a diesel specific one?

I went round and round on my "new to me" 6.9 IDI about using a factory tach in the gauge cluster or aftermarket. I did some homework and here is the short version. It is my understanding diesel tachs need a pulse from an electromagnet signal. You can get an adapter from Dakota Digital that will allow you to use almost any tach with your diesel but the problem is having a "calibrated signal". The aftermarket diesel tachs like Isspro use a kit with magnets that attach to the harmonic balancer. There are some alternators, diesel and gas that will drive a tach, once again the calibration becomes the issue. There are also some diesel tachs that signal off the flywheel much like the Isspro. Autometer, Stewart Warner and others offer diesel tachs but IIRC buying the tach and kit is about $300 or your own tach and the Dakota Digital about $150 and the magnetic signal kit is around $75 but you have the calibration issue. If you are working on an IDI they are pre-wired for a tach from the engine to the gauge cluster. Find a tachometer gauge cluster from the correct year IDI at a pick and pull or ebay and simply swap them out and plug it in. I got an used tach sensor off Ebay for $25 and the tach cluster for $85. It looks clean and correct and is the easiest, cheapest solution. I wanted to get something done faster but in the end it was worth the wait to do it correctly. There is some good tech info on the factory tach in the tech section of the forum.
 

OLDBULL8

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If you would put your truck in your signature, it's easier to answer the question.
 

dirtbiker

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We have a 6.9 installed in a 79 F-150, and have been looking for a solution, too. Since we don't have the option of installing a factory tach cluster (there weren't any in this era of truck) we have been looking at a "tinytach" (http://tinytach.com/diesel.php).
It is a digital tach, but is driven by an included 'transducer" that clamps onto an injector line. Has anyone used one of these before?
 

ididieseler

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We have a 6.9 installed in a 79 F-150, and have been looking for a solution, too. Since we don't have the option of installing a factory tach cluster (there weren't any in this era of truck) we have been looking at a "tinytach" (http://tinytach.com/diesel.php).
It is a digital tach, but is driven by an included 'transducer" that clamps onto an injector line. Has anyone used one of these before?

im in the same boat i put a 7.3 into a 78
 

Hyde

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We have a 6.9 installed in a 79 F-150, and have been looking for a solution, too. Since we don't have the option of installing a factory tach cluster (there weren't any in this era of truck) we have been looking at a "tinytach" (http://tinytach.com/diesel.php).
It is a digital tach, but is driven by an included 'transducer" that clamps onto an injector line. Has anyone used one of these before?

That tach has a very slow refresh rate, its intended for more of a fixed rpm application. I wired an Autometer diesel tach directly to the stator plug on my 3g alt and it works perfectly once you calibrate it.
 

dirtbiker

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They say in their "new features" section that the old one refreshed every 2 1/2 seconds and the new ones refresh every half second. Maybe they are better now? How difficult is it to calibrate the alternator tach?
 

Pino2234

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That tach has a very slow refresh rate, its intended for more of a fixed rpm application. I wired an Autometer diesel tach directly to the stator plug on my 3g alt and it works perfectly once you calibrate it.

Hyde, a year or so ago I wanted to replace my rpm gauge in my 85 F350. I was messing around with a 99 mustang dash and got the tach gauge to read signal from my 3G alternator. I even got the speedometer to work as well. How did you calibrate your Autometer gauge. Did you wire it directly to your alternator or did you strap the probe around it?

They say in their "new features" section that the old one refreshed every 2 1/2 seconds and the new ones refresh every half second. Maybe they are better now? How difficult is it to calibrate the alternator tach?

Has anyone use the new Tiny Tach? Its a toss up between the Autometer Diesel tach and Tiny Tach. They are within $30 of each other. $95 Tiny Tach (w/o shipping) & $125 Autometer 2697 (shipped)
 

riotwarrior

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I have not used the tiny tack however. I can tell you that the tach is based on the same technology that the Kent Moore J33300/A meters use. A line clamp that reads the injection pulses and translates that into an electrical signal.

It is simple and proven method and easy to install and remove to swap to another vehicle!

Not sure on the autometer, however the autometer one I want...is about 350 bucks..so that's on hold a while LOL
 

smolkin

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Not trying to use your thread to sell my old junk, but I still have a new-in-box OEM 87-91 tach that's been in the Marketplace for a few years. It's just the tach gauge, not mounted in a cluster, and would be easy to make work as long as your engine has a good sensor. PM if interested.
 
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