1974 Distributor - tach failure

[Johan]

I want to replace my tach gear coupling, since the tachometer is not working. The cable is functional, so I suspect that just the gear coupling is damaged.
Have anyone experience of this? Can the replacement be done without removing the distributor?

 

[wolf_walker]

Mine's in the same shape if it's any consolation..

 

[Jack]

Pull It

Your cross gear (the small one inside the coupling) is probably toast. You can easily pull it out after removing the threaded brass/bronze coupling from the dist housing. However, the gear on the dist mainshaft may also be damaged (often the case). Due to grease & gunk in the housing and poor viewing angle, it is near impossible to properly inspect the mainshaft gear without pulling the distributor. I suggest you pull the distributor from motor, clean it well and closely inspect on benchtop.
JACK:gap

 

[Jack]

Test this first

Before you remove distributor for inspection/repair ... do this first: Remove tach cable from distributor. Then gently chuck the end of tach cable in a reversible drill motor. Spin the drill COUNTER-clockwise and have a friend look (it's a rather long stretch for me when solo) and see if your tach is working. This test will help determine if you have a problem with tach cable / tachometer.
JACK:gap