Tachometer question
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Burning Brakes
Joined: Jul 2001
Posts: 1,051
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From: Inside every color vette there is a blue one trying to come out!
Tachometer question
Finally for the 1st time since I have owned my 73 vette, I have a working tach. It is the original cable driven tach. I just purchaced an HEI distrib with the manual tach drive & was able to get life out of my tach. IT"S ALIVE !!!! My question is this, once it was working, I noticed a clicking or knocking sound while sitting inside. What could this mean ? Is it just that the tach is old & may eventually need to be rebuilt ? Also I noticed that when I let off the gas, the tach needle seems to drop like a rock almost, it doesn't seem to back down as gracefully as I have seen other tachs, which were probably electric tachs...is this something that is intrinsic to manual cable tachs or could it be that it needs to be rebuilt because of it possibly being old & loose?
Team Owner
Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
once it was working, I noticed a clicking or knocking sound while sitting inside.
Tried to stop "that" ticking noise on the original tach. Bought another (used) tach. Same ticking noise. Replaced the speedo-type cable. Slightly different (but still audible) ticking noise. Removed the 90 degree gear drive from the distributor and ran the mechanical cable straight to the distributor (rotating the distributor 45 degrees clockwise). Same ticking noise.
Finally for the 1st time since I we've owned our 73 vette, I have a silent working tach.
How??? I converted the tach over to a 1975 electronic mechanism. I still used the 1973 dial face and pointer - so fromn the outside it looks 100% original.
The speed cup shaft and support bearings get worn and allow a slight wobble. The fix is to send out the mechanical tach to someone with the knowledge and parts needed to rebuild it.
If your's was like mine; the ticking is worse at certain RPM's than others.
I am now repairing 1975 through 1982 electronic tachs and converting 1968 through 1974 mechanical tachs.
If interested, email me.
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Last edited by Mike Mercury; Jan 26, 2005 at 11:39 AM.
Thread Starter
Burning Brakes
Joined: Jul 2001
Posts: 1,051
Likes: 0
From: Inside every color vette there is a blue one trying to come out!
Thanks for the insight. For right now I will live with the ticking, I am just happy to have that needle moving like it should.
