Tachometer / RPM gauges

Looking for suggestions; RPM gauge, Perkins 6-354.
Has anyone replaced the original alternator driven tachometer with electronic pick-up type sending unit and gauge, and if yes, what product did you use?
Thanks in advance for any input.

Would like same.
Wish list:
12-24 VDC
3 3/8" hole mount
Digital readout with backlight
Injection line pulse or magnetic pickup transducer
20 ft or longer cable to transducer
Hourmeter that can be preset to old tach hours.

May have to settle for TinyTach.

I think it's a great idea. I had mechanical gauges and the shaft key was repeatedly shearing. Certainly don't want to rely on an alternator signal. Hope it works out for you.

Literally just last weekend I tackled my fly bridge tach to try to adjust it to the lower helm ("3 helm" selected instead of"2"). Turns out the selector broke off in that position so I'm following this thread with interest!

To me, the Tiny-Tach is a great find thanks to High Wire. Inexpensive, small, digital readout and the transducer just clamps around one of your injector (atomiser) lines.
I'm just waiting to find out if one transducer can supply two station displays or if each one needs its own transducer sending unit.

I replaced my flybridge tach a few years ago, used 82302p -
go to this defender page to see it - still Alternator driven however -

https://www.defender.com/product.jsp?path=-1|311|2349076|2349084&id=1383892

I replaced the other gauges there at the same time so everything looked right.
total cost at the time was about $150 - would guess a little more now.

Capt. Joe said:

Looking for suggestions; RPM gauge, Perkins 6-354.
Has anyone replaced the original alternator driven tachometer with electronic pick-up type sending unit and gauge, and if yes, what product did you use?
Thanks in advance for any input.

Click to expand...

Yes, did both my mains. My Perkins 6.354's had a cover plate over where the mechanical (magnetic) tach pick-up was originally installed, before they went to alternator-based tachs.

Aetna Engineering sells these units which replace the cover plate:


Go to their web page and scroll down till you get to "8875: Adapter."

This feeds a Noland RS-11 which puts the RPM data on the NMEA 2000 backbone. From there I can display the data on my main chartplotter or a Lowrance LMF-400 multi-function gauge on the dash.

You could of course hook it up to a traditional tach gauge, too.

I like having it on the chartplotter. I've set it up so the RPMs always display on my normal chart viewing page, one on each side of the screen (port and starboard.) The LMF-400 also has a "synch" option that displays a pointer which is exactly centered when they're in synch. Usually it's easier to do by ear and by the numbers, but some people prefer a dial.

I would contact Lauderdale Speedometer https://www.lspeedo.com/ They are experts in several solutions.

Look at it this way, if your tach suddenly stops working you probably lost your charging system, bet you'd notice this faster than an amp meter showing a slight discharge or a volt meter dropping to 12 ~ volts? don't ask how I know this...

Capt. Joe said:

Has anyone replaced the original alternator driven tachometer with electronic pick-up type sending unit and gauge, and if yes, what product did you use?

Click to expand...

Can't speak to the changing-the-sender part of it, but we replaced our original analog mechanical tachs with Aetna digital tachs. We just chose a version that works with our existing magnetic senders, but they may have other options. Easy installation, drop in to our existing dash holes, etc. Seem to work like a champ.

CruzPro makes digital tachs, too, but I don't have experience with those, dunno if they support sender options. Theirs just happened to be too small in diameter for our existing holes.

-Chris

Good point about the tach giving you an indication that your alternator is working. This may be important to someone who's not used to monitoring gauges underway.

Personally, I tend to keep an eye on the voltage gauges. Another benefit of that is when the smart regulator brings the voltage down, I know my house bank is charged.