C1 tach repairs

[Ed Jennings]

I have removed the tach from my 61 to change the face and lens. How is the needle supposed to be removed/replaced? Also, is any lubrication of the tach mechanism required? The needle frequently did not return to zero (stayed at about 500 RPM with engine off), but seems to be free now that it has been removed and the dust blown out.

Here's one for the numbers guys: The tach is dated Oct 60, which is consistant with the car's Dec 60 build date. On the back of the tach face, is the date 7-24-64 K in pencil. Service replacement? Calibration date?

[Joe L.]

Re: C1 tach repairs

Ed----

I have no direct experience with a '61 tach. However, with respect to needle attachment, I believe that all Corvette tachs are essentially the same. As far as I know, the needle is simply a "press fit" on the shaft. Using extreme care and a delicate hand, I believe that the needle will pull off the shaft and is re-installed by carefully pressing onto the shaft. However, hopefully somone with more experience than I will be able to offer additional info.

I do not believe that the tach mechanism either requires or should be oiled. Corvette tachometers, although of the mechanical type, are not direct drive. Direct drive type mechanical tachs, as found in racing cars, are a much more expensive component than GM wanted to get involved with.

As a matter of fact, in my experience, rebuilding of the Corvette tach mechanism often proves less than satisfactory. That's because there is a 'dampening' feature built into the tach mechanism to limit 'needle bounce' and oscillation, which is an unwanted by-product of the Corvette's non-direct drive tach mechanism's operation. For some reason, restoration of this 'dampening' just never seems to be satisfactory. The best bet is to replace the mechanism entirely with a factory new unit. Ecklers and others sell these units for about $75.00 and you can install one yourself using your original needle and face plate. I believe this part is still manufactured by GM, but it is not available through the GM parts system. It is one of those items that is available only through the Delco parts system. I believe I've found the part number, but I won't post it until I'm sure it's the right one. I'm working on that now, as a matter of fact.

[Ed Jennings]

Re: C1 tach repairs

As a matter of interest ot anyone else reading this thread, the needle does NOT pull off. It is a threaded fit, and unscrews rather easily. When replacing it, it takes a bit of fiddling to get the tach to register zero, but no big deal.

[Joe L.]

Re: C1 tach repairs

Ed----

Sorry for the "bum steer". Usually, I stay away from C1 questions since I have very little knowledge or experience in that area. However, when I see a question go without any response for a considerable period, I sometimes jump in and offer what I can based on my C2 and C3 experience. I'm going to have to try to control that tendency.

[Ed Jennings]

Re: C1 tach repairs

Joe,

No sweat, no damage done. I too, ocassionally give a bum steer, usually from a bad memory. Your responses are usually right on the money.