Converting from mechanical tachometer to electronic

[Tampaparadise]

Hi Gents,

I looked around the forum and I am sure it is somewhere but I failed to find it. My 79 Hat with 8v71ti Detroits with mechanical tachometers have been stubborn, intermittent and now are defunct/dead. What have others here replaced with in electronic/electrical type?

Mark

[MikeP]

If you are replacing them because of intermittent or faulty operation, the problem might be easily fixable - either electrical, as in bad connections - or mechanical, as in drive cable replacement. Do you have a synchronizer? If so it could be the short cables from the synchro drive to the tach drive.

There are a variety of "modern" instruments available from a variety of suppliers I'm sure folks who have replaced them will chime in if they haven't already.

Oops...I just now re-read your post that they are, if I understand correctly, mechanically-driven tachs, not electrical tachs with drive cables from the engine/synchronizer to tach-drive sensors. In that case, obviously there is no electrical issue involved.

[Scarlett]

My boat had Aetna digital tachs at the lower helm and I liked them so much I also put a set on the upper helm. You need a sender unit to replace the one you have on the engines. Customer support from Aetna is fantastic. John

[scottinsydney]

About a year ago I removed the old depth sounder from my dash console, and installed two CruzPro RH60 digital tachos using the same surround and new laser cut aluminum faced perspex. The CruzPro units also have a total time and elapsed time function .. great as my engine room hour meters no longer work. Easy to install and have been faultless. Check out www.cruzpro.com

Tachos.jpg

Disclosure: I do own a boat parts business and have been selling Cruz Pro products for 18 years. However this is a really good product and so useful. The old inaccurate Tachos are now only for ornamental display.

[Nonchalant1]

If you don't have FloScan diesel use meters, you might consider getting them as they have perfect digital electronic tachs and also tell you how much fuel you are really using and how much you really have left. I put them on my 53MY with 8V71TIs and the FloScans require 2 rather easy to install fuel line sensors and a reflector for the laser tachometer sensor, but they are a great investment and the tachs are good to within 1 RPM or so.

[mykim]

Hi Gents,

I looked around the forum and I am sure it is somewhere but I failed to find it. My 79 Hat with 8v71ti Detroits with mechanical tachometers have been stubborn, intermittent and now are defunct/dead. What have others here replaced with in electronic/electrical type?

Mark

As is soften the case your not getting an answer to your question. Answer, you will still need a pair of tach cables to run a pair of electric tach sending units. Then it is a matter of running a set of wires from the senders to your new tachs. I would suggest you call Lauderdale Speedometer in Ft Lauderdale. They are the wizards on this stuff and can likely offer good advice.

Cheers

[scottinsydney]

In the case of the Cruz Pro RMP gauges, the wires are +, - and connect to the sender wire on the back of the old tacho. The + & - for the instruments should be 12 volts. Installation job done.

To Calibrate: If you do not have a Floscan already installed with tacho, you can buy a photo tach at Radio Shack, mark the shaft and do readings (as someone else drives the boat). The CruzPro gauge is very easy to calibrate and also has sensitivity settings for the sender signal.

I also like the total time function.