Cable Drive Tachometer Question?
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Cable Drive Tachometer Question?
On a cable drive tach (72) is there a componenet in the tach which keeps the needle from bouncing? My tach works, but has recently become very inaccurate and the needle bounces when when I let off the gas. :skep: Thanks!
Le Mans Master
Joined: Jul 1999
Posts: 9,206
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From: Sewell NJ
Re: Cable Drive Tachometer Question? (cor72vette)
It's probably binding of the cable. I believe you can remove the inner drive cable without getting under the dash. Just unscrew the cable from the distributor and pull the cable inner cable out. Lube it with speedometer lube and then slide it back in. Make sure it's fully seated when you get it back in by turning the cable until it's in as far as it will go. Then reconnect it to the distributor and try it out.
Le Mans Master
Joined: Jul 1999
Posts: 9,206
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From: Sewell NJ
Re: Cable Drive Tachometer Question? (cor72vette)
Actually, I have replaced the cable so I doubt it's binding. :( Any other suggestions?
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Re: Cable Drive Tachometer Question? (vettfixr)
ok, I just put my dewalt on the cable and the best I can determine is the needle still bounces. :cuss So, I guess it's in the tach itself. Any reccomendations for rebuilding it myself or sending it somewhere? Cosmetically the tach is perfect, it would be a shame to discard it. Or where might I find an excellent quality used one?
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Le Mans Master
Joined: Jul 1999
Posts: 9,206
Likes: 17
From: Sewell NJ
Re: Cable Drive Tachometer Question? (cor72vette)
The only place I know offhand is Clocks by Roger. He shows his stuff at Carlisle and the work is excellent. If I remember right he was pretty dear as far as prices go. This might not make a difference if you want to keep your original parts. You might want to check with ZIP or Mid America to see what a replacement costs also. I replaced mine years ago with one from Mid America and I don't think anyone could tell that it's a replacement.
Team Owner
Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
Re: Cable Drive Tachometer Question? (vettfixr)
if it does this with a drill spinning the cable; then probably the magnet is rubbing against the speed cup (inside the tach). You would need to remove the tach and either:
* straighted out the wobbly speed cup, or
* replace the main shaft housing due to the bearing surface being enlarged... causing too much side play.
one other possibility is that the cable is slightly too long (the cable... not the outer casing). With pressure trying to push each end of the cable towards each other... it will try to flop around in the casing. It this were the problem, then you would of seen good results with your electric drill experiment.
* straighted out the wobbly speed cup, or
* replace the main shaft housing due to the bearing surface being enlarged... causing too much side play.
one other possibility is that the cable is slightly too long (the cable... not the outer casing). With pressure trying to push each end of the cable towards each other... it will try to flop around in the casing. It this were the problem, then you would of seen good results with your electric drill experiment.
Melting Slicks
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From: Where are the Smoky Mountain Cruisers? Not Correctly Restored Stingray
Re: Cable Drive Tachometer Question? (Mike Mercury)
I bought a aftermarket cable, I think my inner cable is too short. It's driven me crazy.
Le Mans Master
Joined: Jul 1999
Posts: 9,206
Likes: 17
From: Sewell NJ
Re: Cable Drive Tachometer Question? (cor72vette)
You know a cable driven tach isn't really all that different from a cable driven speedometer. Maybe you could check your yellow pages or a few local speed shops and see if there's anyone in your area that does speedometer repairs. You might be able to have them check it out or purchase whatever parts are needed from them. Or take a look in Hemmings where I'm sure you'll find a ton of repair facilities. Just a thought.
