My Tach stopped working last night on my 71. Any ideas were to start? Everyting else is still working fine.

I would look at the cable first. Sometimes the ends will pop out. Do you hear any loud clicking from behind your tach? The cable may also just have given up the ghost and broken. If you determine it is the cable, you might want to hook up the adaptor that Ecklers and Mid America sells. It fits onto the dristributor between the cable and the distributor and takes out the 90 degreee bend that the cable has to negotiate. They sell two different units. One is about a 6 inch cable that in effect just adds length to the tach cable so the bend is not so radical and the other is an actual 90 fitting that takes the bend out of the cable completely. There is a major difference is price with the fitting being the more expensive unit.

The original cable inner core ends were plastic which get brittle and can break off. You can easily check the end of the cable on the distributor. Otherwise to check the end on the tach you need to pull the dash out enough to get a hand back in there. I just wrote an article for Corvette Fever (October 2002) with step by step photos on the procedure. It could be that the cable inner core has bound up. Did you hear noises (clicking sound with RPM) before it failed? ~Juliet

Many times the distributor cross shaft is the culprit of a inop tach. If you disconnect the tach cable and manually turn it with your fingers in both directions, a helper should be able to see the tach needle jump. If this happens, your tach cable is good. If the drive cable pulls out of the sheath, obviously the cable is bad.

If the cable is good, then the cross shaft is suspect. You can start the car with cable disconnected, and look to see if the drive is turning. If not, a rebuild kit is available. These can be problematic in that the main shaft needs to be replaced along with the cross gear. You may be better off purchising a new tach drive distibutor.

After you have the tach working, you should lube the cross gear at least once a year to prevent future damage.

Alex

Thanks for all of the info. I am sure the cable has bound up. I haven't had time to replace it yet but hopefully I will soon. When I took the cable off I couldn't turn it either way. Hope it doesn't turn out to be another huge job.
Thanks Again

If the cable is bound up, you will want to take a close look at the distributor. The cross gear and shaft are fragile and may require replacement.

Alex