6-cylinder Tach

[sphinx]

Now that I have the tach working correctly, I have to integrate it into the non-tach dash cluster.
I removed the non-gauge cluster from my 1978 parts truck to experiment with so if I break something, I still have the one from 1976 to put back in the truck.
The first photo below shows the differences between the 76 and 78.  The 76 only has a single indicator light in the large fuel gauge for the seatbelt warning.  The 78 has two, one for the seatbelt and one for the break.  Also, the 78 has a second opening on the speedometer which I can assume was used to attach a cruise control speed sensor of some type.
As I am replacing the fuel gauge with tach, I will need to move the fuel gauge to one of the other smaller indicator light position in the left side of the cluster.   The factory location for the smaller fuel gauge is the lower left position now occupied by the break indicator.  Now given that a break indicator is in the lower fuel gauge on the 78, I could use the 78 cluster and just rewire the indicator from the left side to the right center location.  As I have the break light/seat belt bezel, which is a dual indicator, which just happens to fit in lower portion of the tach, this seems like the logical way to go.

The tach is mounted to a carrier, which is then mounted to the cluster with three screws.  A access hole was needed to connect the tach harness to the back of the tach.  I “eye balled” the location of the harness connector and cut it out with a Dremmel tool with a cut-off wheel.  I did not want to take the change of breaking the somewhat brittle cluster by using a cutting bit, the cut-off wheel just simply melted the plastic without placing any stress on the cluster.

As the indicator lights in the fuel gauge for the 78 was only configured for the seat belt indicator, I will have to cut out the partition and wire the seatbelt bulb to the brake circuit.   I’ll block-off the seat belt indicator as it is somewhat useless today as we all to obey the seatbelt laws and “should” be in habit of always wearing our seatbelts.
Now with the conversion and installation of the tach finished, I have still to add a fuel gauge of some sort. 

[sphinx]

More pics . . . .

[Jason S]

This has been very interesting to follow.

So you wire up a small tach cluster gas gauge into the bottom left hole or do you plan something else?

[sphinx]

I'm looking at making a 5 or 8 segment LED readout to put in the lower left interment hole.  I don't have the clear lens part to cover a small fuel gauge from a gauge cluster dash.  I keep posting my ideas and progress.

Thanks for reading.

[sphinx]

For details on my attempt to make a LED fuel gauge see this thread: http://forum.73-87chevytrucks.com/smforum/index.php/topic,26269.0.html

[heavychevy91]

This thread is very cool. I enjoyed reading it and learned a bit too. Looks like you do good work and I look forward to seeing more.

[sphinx]

Thanks for reading Heavychevy.  I like to document my projects here so I don't forget what I did.  My memory is about as rusty as my truck.  I can hopefully fix my truck, but for my memory there is no hope.

[dalefan613]

great article  im looking at picking up the tach at classic industries will the carrier come with  the tach?

[sphinx]

Dalefan613,
I'm not sure about the carrier.  That is just what I called it as it has the mounting tabs that line up with screw holes.   You should ask the person you order it from.  Sorry I can't be more specific.