I HAVE A 1972 CORVETTE LS5 454/400 TURBO TRANS. THE TACH JUST QUIT. IT IS GEAR DRIVEN FROM THE DISTRIBUTOR. (NOT ELECTRIC) DOES ANY ONE HAVE ANY CLUES WHAT PART MIGHT BE BAD BEFORE I TAKE IT APART. THANKS ERIC
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Re: TACHOMETER QUIT
Unscrew the tach cable from the distributor and pull it out. Then remove the gear that the cable mates to. More than likely a few teeth are missing on the end of the gear. While you have the cable detached, use a drill to turn the cable and look to see if the tach needle is moving. That will tell you if the cable is broken or not. -
Re: TACHOMETER QUIT
When mine quit, it was the gear on the distributor shaft that drives the tach cable.Comment
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Re: TACHOMETER QUIT
Eric this has happened to my 68 and my 70. Each time it was the gear. In both cases the distributor shaft and the tach drive gear had to be replaced.
If this is your problem while your distributor is out to replace the shaft remove the top plastic seal and clean out the old dried grease and replace the grease and put in a new seal.
If you look in the archives you will find the recommeded grease as posted by Joe Lucia to be GM #12377985.
Failure of the tach drive is usually becasue of lack of lubrication. I am guilty with others for not servicing the tach drive with lubricant. It won't happen again though.Comment
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Re: TACHOMETER QUIT
Hello Jim, did you installed the famous set screw in your 70. What is your experience concerning durability.
Roberto, NCRS #30019, RMCComment
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Re: TACHOMETER QUIT
Roberto I did not install the set screw. When I had to replace the shaft and gear in my 70, about 1973, I just used new parts. It was still working when I pulled the engine about 6-7 years ago when I put in the ZZ1 crate engine with a HEI distributor that is still in use. The one in my 68 gave out a few years ago. I have the new parts, just have not got around to changing it out. I need to get some of that special GM grease for the upper cavity.Comment
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THANKS! *NM*
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