'71 Rallye Cluster Tachometer Responsiveness to Engine RPMs

[road robert]

I recently bought a '71 rr (383 original points ignition) with a broken tachometer (stuck on 2000) and sent the entire cluster to Gary the Tachman in S.C for repair and calibration. I installed it yesterday and although the tac works, it is slow to respond when increasing and decreasing RPMs, sort of "floats". Is this normal behavior for an original 7000 RPM rallye tachometer? The only new replacement I could find was the 8000 RPM replacement and want to keep car as original as possible. Thank you!

 

[Russ69Runner]

Is their something wired wrong. Or somethin interfering with the wire to the coil. I would call the tach man and ask him he may know what to do also.

 

[road robert]

I checked the continuity of the tac wire from the back of cluster to the negative terminal on the coil with a DMM it is fine. Sent an e-mail to the tach man, he tested and verified calibration OK: I just want to know if this is just the way these original tacs were... Wiring is pretty much unmolested, however the tac wire was spliced at some point but seems to be fine.

 

[Russ69Runner]

fielding could be a problem. Current flowing from a wire close to it could give you a false reading. Or cause it to float. Maybe one of the other guy's has had this problem or know why it is doing what it is doing. Just some thought's. Never seen one do that. Did have one after market and it acted funny and was a wire too close to it from the alternator.

 

[69hemibeep]

Hate to say it but factory tach's suck. Mine has one and it still had a sun tach on the column. the one in my car has been restored twice and it is still slow

 

[RAINMANYEH]

I’d redo the spliced tach wire as it could be that wire has corrosion, broken wires, or bad connection at the splice.