My idle is set right at 1K RPM, but sometimes when coming to a stop, the tach reads 1400. If I tap on the glass it will fall back to 1K. What would cause the tach to stick like that?
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The jewel movement of the indicator needle. They wear out. Some faster than others.
Hmm. That's not the easy answer I was looking for, but makes sense.
Two notes:
first, ALL Panteras 71-87 plus all Mangustas use the same basic speedo and tach. Pantera 90s use an electronic speedo driven off a sender on the usual right-angle gear drive but I haven't seen one apart. The faces of Euro speedos were lettered metric, and the gear drives- one for the speedo and one for the odometer inside were a little different, according to the ZF right-angle drive ratio used.
Second, by carefully unbending the chromed-brass bezel about 2/3 of the way around the gauge with a little flat-blade screwdriver, the case can be removed for access. Note- you can only do this maybe twice before the brass work-hardens and cracks, so be slow, careful and don't bend more than about 1/2 way.
Inside the tach, there is a printed circuit board a little bigger than a postage stamp with a dozen or so components, and the usual coil-spring needle drive. External oiling cannot reach the needle works.
Palo Alto Speedometer and a couple of places in the L.A. area can do this repair better than we can, mail order, for a charge. They may also have extra bezels if one cracks.
first, ALL Panteras 71-87 plus all Mangustas use the same basic speedo and tach. Pantera 90s use an electronic speedo driven off a sender on the usual right-angle gear drive but I haven't seen one apart. The faces of Euro speedos were lettered metric, and the gear drives- one for the speedo and one for the odometer inside were a little different, according to the ZF right-angle drive ratio used.
Second, by carefully unbending the chromed-brass bezel about 2/3 of the way around the gauge with a little flat-blade screwdriver, the case can be removed for access. Note- you can only do this maybe twice before the brass work-hardens and cracks, so be slow, careful and don't bend more than about 1/2 way.
Inside the tach, there is a printed circuit board a little bigger than a postage stamp with a dozen or so components, and the usual coil-spring needle drive. External oiling cannot reach the needle works.
Palo Alto Speedometer and a couple of places in the L.A. area can do this repair better than we can, mail order, for a charge. They may also have extra bezels if one cracks.
I was told that the jewel movement does not get lubricated by a tach service tech. What do I know. I'm just a gorilla in a China shop? The orangutans are the intellectuals?