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View Full Version : Tach options other than off the alternator



McKee
04-26-2010, 05:19 AM
So I set up a high output externally regulated alternator on my boat, so far the only downside (aside from it being &^%*-ing expensive) is that I don't have a reliable tach for the engine. How have you all gotten around the problem?

carioca1232001
04-26-2010, 06:00 AM
For some time now, the following device has been on my wish list:

http://www.tinytach.com/tinytach/diesel.php

One advantage is that it is non-invasive, as the sensor simply clamps on to the diesel injector line (or spark-plug cable, for petrol engines).

A rotating pointer for the display would have been preferable, as it is more appeasing to the senses.

Most other non-alternator-driven tachs require some form of proximity-coupling (or visual coupling) to a rotating part such as a flywheel, main front pulley etc. Not sure if these are maintenance-free.

McKee
04-26-2010, 06:08 AM
Thats pretty cool, and it doesn't break the bank.

carioca1232001
04-26-2010, 06:25 AM
Glad that it can be of some utility to you. A year or so ago, it was listed at 150 bucks.

Hope it lasts as long as the 12-month guarantee !

Garret
04-26-2010, 06:52 AM
Hi -

I don't know what brand you have, but my Balmar HO alternator has a tach output. Are you sure yours doesn't?

Thought I'd ask.....

If it doesn't, you may find that a good auto electric shop can add one.

carioca1232001
04-26-2010, 07:29 AM
Alternator-driven tachs are prone to error due to belt slippage, and consequently require constant supervision.

Adding a tacho-output to an alternator is readily done, provided one has access to the electrical connections of the rectifier diodes.

BBSebens
04-27-2010, 03:32 PM
i used to work on raspberry harvesters that used a magnetic sensor connected to an appropriately calibrated gauge to give a tach reading. the sensor screwed into the flywheel housing and picked up the teeth passing by.

Inexpensive, simple, reliable.

Breakaway
04-27-2010, 03:42 PM
What engine is it? Is it electronically controlled? If so yuo can output engine speed from the ECM either to a digital display or to "digital gauges" if you like a needle pointer ( I do)

Also, Livorsi Marine (http://www.livorsi.com/catalog/tachometers.htm#DIGITAL_TACH_) offers tachs that are either alternator,mechanically, or magnetic probe driven for gas and diesel. They are dials with needles.


SPECIALTY
ANALOG TACHS
GAS and DIESEL

3 3/8� CUTOUT,
3 3/4� OVERALL Diesel or gas tach with standard cutout
Choose alternator, mechanical or magnetic probe driven
Carbon fiber and super rim available Add
RPM Add
DIAL COLOR Add
S for
SUPER RIM Add
RIM COLOR Part # example
GL
8000 W S R
http://www.livorsi.com/images/07catalog/waterproof/GL10000PLBK.gif
GL - DIESEL 4000 Alternator driven 4000DA 4000 Mechanical generator driven 4000MSGD Mechanical signal generator GLMSG Drive tips GLDT 4000 Magnetic probe driven 4000MPD 5000 Magnetic probe driven 5000MPD Magnetic probe sender GLMP Probe wire GLPW GL - GAS 8000 Inductive kit/Merc race engine 8000IP** 10000 4, 6, 8 cyl., & outboards 10000 12000 4, 6, 8 cyl., & outboards 12000
BlacK
Carbon Fiber
PLatinum
White

Add this rim
add a real
color kick
to your dash!

Black - BK
Blue - BL
Chrome - CH
Lime - L
Mustard - MU
Orange - O
Platinum - PL
Purple - PU
Red - R
Tangelo - TA
Teal - T
White - W Diesel From $249 Gas From $249 Gas Inductive Pickup From $---
Add $12 for colored rim, $13 for super rim
Magnetic probe sender GLMP $94 Probe wire GLPW $54 Mechanical signal generator GLMSG $94 Drive tips GLDT $69

http://www.livorsi.com/images/07catalog/waterproof/GL10000PLBK.gif


Kevin