From: Jim Newton (jnewton@laurel.com)
Date: Mon Mar 17 2003 - 10:56:51 PST
Hi Nathan...
There are diesel tachometer kits around, but they're not cheap. Just
do a Google search for the keywords diesel tachometer kit. They
include one or two magnets that you attach with epoxy to the
crankshaft pulley or harmonic balancer (or even the flex plate) at
180-degree positions. The kit also comes with a magnetic sensor that
you mount adjacent to the magnets. Then you run a wire up to your
dash and you're done.
Most people don't realize this, but you can also use a standard
tachometer on a diesel vehicle (you can select a tachometer that
matches the "look" of the CUCV's instrumentation). To do this, simply
set the tachometer to 4-cylinder mode and attach 2 magnets to the
crankshaft line as described above. Then get a "proximity sensor"
from any electronics shop (like Jameco, something like
http://www.jameco.com/cgi-bin/ncommerce3/ProductDisplay?prmenbr=91&prrfnbr=4392&cgrfnbr=501&ctgys=)
and mount it adjacent to the magnets, and run the wires up to your
tach where the points would usually connect. This can be a cheaper
and more flexible solution since you are not stuck with the small
selection of diesel-only tachs out there. The downsize is that most
diesel tachs have lower maximum RPMs on the dial, and gas engine tachs
have dials with higher RPMs.
You have to set the tach to 4-cylinder mode because on a gas engine,
the points fire one time per cylinder per 2 revolutions of the crank.
That means that in a full 4-cycle cycle, the points fire 4 times for 2
revolutions of the motor. This means that the points fire twice per
each single revolution. If you place 2 magnets 180-degrees apart on
your diesel, it will simulate the points closing twice per revolution
and will indicate the proper RPM.
Good luck!
>Has anyone used an aftermarket tachometer on a CUCV? Of all the guages I
>wished I had, engine RPM would be the nicest 'other' thing to know, so I've
>been thinking of getting an aftermarket tach. Since most tachs hook to the
>ignition system (which doesn't exist for a diesel), the only diesel
>alternatives I've seen involve wrapping a sensor around an alternator to
>register the number of rotations (actually poles) on your alternator to
>measure engine RPM. For example, AutoMeter has a model 2888 diesel
>tachometer that I'm thinking of getting (but it requires a messy calibration
>in a shop). If anyone has ever used one of these products (or has
>recommendations) please let me know.
--Jim "Ike" Newton
o 1984 M1007 CUCV Military Suburban 6.2 Liter (378 CID) Turbo-Diesel Engine 5/4 Ton Cargo Capacity, 4WD
o 1971 M35A2 Military Troop/Cargo Truck "Deuce and a Half" 478 CID Turbo-Diesel Multi-Fuel Engine Air Shift Front Axle 2 1/2 Ton Cargo Capacity, 6WD
See them at: http://www.CUCV.net
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