Tachometer
My Diesel came with the big clock rather than a tachometer and I just had to have a tach to go with the new V8 engine.
Volvo tachs came in two flavors; 4cyl and 6 cyl both of which will work with the V8 with calibration and/or modification. Of course, the 4 cylinder versions are much more common and less expensive that the 6 cylinder ones. The 6 cylinder version can be calibrated by an internal adjustment potentiometer to correctly display the 8 cyl signal.
The 4 cylinder requires the addition of a 750 ohm resistor in the meter movement circuit to get within range of the internal pot. The resistor solution to this issue was the product of ‘Jags That Run’ and is published in their SBC swap manual. The indicator is a press fit on a needle like shaft. Carefully pull it off in order to remove the tach face for access to the circuit board. Just press it back on.
Replacement is a few screws from the back of the circuit panel. Both the clock and tach plug into the circuit board with 5 connectors, three at the top and two at the bottom, and they may be a little difficult pulling out. Gently pry the clock/tach up, evenly, with a blade screwdriver. The tach plugs into the instrument panel the same way but without the external light connection leads.
On the tach unit the three connectors at the upper side of the device connect to a small wiring harness that powers the small clock in case you want to add it to the aux instrument area. If you are planning on adding the small clock be sure to get the little harness. The single connector at the bottom of the movement is the PCM tach signal input.
And here is what the new instrument panel with the tach looks like.
The clear cover of the panel has a hole for the clock adjustment stem and the cars with tachs have a blank plug to seal that hole. If you are buying a tach rather than installing a V8 in your tach equipped car be sure to get the plug when you are acquiring the tach.
The parent document to this thread can be found here: http://forums.turbobricks.com/showthread.php?t=250257
My Diesel came with the big clock rather than a tachometer and I just had to have a tach to go with the new V8 engine.
Volvo tachs came in two flavors; 4cyl and 6 cyl both of which will work with the V8 with calibration and/or modification. Of course, the 4 cylinder versions are much more common and less expensive that the 6 cylinder ones. The 6 cylinder version can be calibrated by an internal adjustment potentiometer to correctly display the 8 cyl signal.
The 4 cylinder requires the addition of a 750 ohm resistor in the meter movement circuit to get within range of the internal pot. The resistor solution to this issue was the product of ‘Jags That Run’ and is published in their SBC swap manual. The indicator is a press fit on a needle like shaft. Carefully pull it off in order to remove the tach face for access to the circuit board. Just press it back on.
Replacement is a few screws from the back of the circuit panel. Both the clock and tach plug into the circuit board with 5 connectors, three at the top and two at the bottom, and they may be a little difficult pulling out. Gently pry the clock/tach up, evenly, with a blade screwdriver. The tach plugs into the instrument panel the same way but without the external light connection leads.
On the tach unit the three connectors at the upper side of the device connect to a small wiring harness that powers the small clock in case you want to add it to the aux instrument area. If you are planning on adding the small clock be sure to get the little harness. The single connector at the bottom of the movement is the PCM tach signal input.
And here is what the new instrument panel with the tach looks like.
The clear cover of the panel has a hole for the clock adjustment stem and the cars with tachs have a blank plug to seal that hole. If you are buying a tach rather than installing a V8 in your tach equipped car be sure to get the plug when you are acquiring the tach.
The parent document to this thread can be found here: http://forums.turbobricks.com/showthread.php?t=250257
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