Hidden tachometer and gauges

Now you see them, now you don't:

1964 Buicks have a pretty large ash tray right under the radio, in a very visible and convenient spot to look at. After seeing others make such modifications to this area such as radios and large round gauges, I was motivated to add some hidden gauges. All parts are slide in, so no damage was done to the car and the original ash tray could be replaced.

I started with a Supro LED tach and LED triple gauge cluster. They discontinued these in the 90s, but it was just the look I was wanting. However, when I first started off, I couldn't get the triple gauge hidden.

I originally had the tach mounted in the ash tray sans its case and the gauges surface mounted to where the ash tray handle was, and the ash tray handle mounted to the gauges.


The gauges come apart.

Notice each module has a separate logic board and LED board. In the modified installation, the logic board were remotely mounted so just the LED driver boards were mounted in the ash tray.

 
I removed every individual LED, painted everything but their fronts black so they wouldn't bleed to each other, and soldered them to the circuit board. The final design has three more illumination lights at the bottom.

The mask around the LEDs was printed on a transparency backwards so that the toner is on the side facing away from the gauges for an even look. 


Here is the completed ashtray unit. The two LED driver boards are at the top and bottom, with plastic secured to them with double sided tape for insulation. Due to the tight dimensions of the ash tray opening, a standard case wouldn't work. They are soldered to the LED circuit board, shown to the right. A DB25 carries the remote signals from the logic boards to the driver boards.

This is the inside of the logic board enclosure. Once again, a custom plastic case. The DB25 connects to the ashtray assembly, and the white cable is a multi-core cable that carries the voltages from the sensors.


Here are the two hooked together. Using gray hook and look adhesive backed fabric, the gray enclosure was placed in the dash under the glovebox opening, hidden from view.


Here it is fully illuminated.

The finished product, installed.

 

Oil Pressure Sender
In 2021 the oil pressure sender had to be replaced. Over time removing and reinstalling the electrical connection caused the stud to just spin within the housing and not make contact, resulting in no pressure reading. The Sunpro name, a registered trademark of Snap-On since 1980, has gone through a number of licensees including Sunpro, Actron, SPX, and Bosch, so it took some time to locate a replacement sender. The following are all part numbers for the replacement unit for the 0 to 100 PSI 330240 ohm sender:

SunPro CP7577   Actron SP0F000011   Bosch FST 7577

Left, old sending unit. Right, new sending unit. New unit was $24 before tax in 2021 dollars.

Other notable gauges

Mike (64 wildcat conv) used Chevy Nova SS Gauges to place gauges where factory lights originally were:
http://www.v8buick.com/index.php?threads/64-wildcat-with-rare-factory-gauge-package-found.309540/

Source: left, eBay. Right, Mike.

Dakota Digital has instructions and makes a package to mount their VHX series gauges in a Riviera cluster:

Source: Dakota Digital

Both of these solutions requiring cutting the bosses out that held the original indicator lamps.