Just a question. Can the tach drive gear in the dist. be replaced without having to remove and disassemble/rebuild the dist. My vehicle is a 72BB with original points type dist.

Thanks guys.

 

Yes.

1. Unscrew tach cable
2. Use big *** screw driver to remove 'fixing nut/bolt' or whatever you want to call it
3. Gear comes out.

 

You can replace the driven gear without disassembling the tach. However, if the problem is the drive gear, you will have to take it apart. Pull the driven gear out, get all the grease off and you should be able to tell which is the problem [if not that both are worn out]. If your tach is 'jumpy' it could be that the cable just needs to be lubed. The dist. gears are probably the least likely cause of tach problems...but if never lubed, that could be your problem.

 

Thanks guys, I'll try lubing the cable. It worked fine then quit and when it feels like it it gets jumpy.

I'll let ya know

 

If the small cross (tachometer) gear is bad, the odds are the main shaft distributor gear is also bad.

I hate to say it but many times customers buy just the tach drive cross gear only to discover after they eat the second gear up, the main shaft gear is bad. This only leads to buying two of the cross gears and throwing money away.

Before you purchase just one gear, do inspections on the main shaft gear and the distributor housing wall where the cross gear rides. Later cars, the tach gear has a Teflon button that it rides on and when it wears out the tach gear will have excess play.

On earlier cars there is no button and the tach cross gear rides on the distributor wall. Over time the gear will eat away at the side of the housing. Evidence of this is a small tit on the wall left from the original gear. If you look in the distributor you will see a wear pattern the size of the end of the cross gear with a tit in the middle.

Another culprit that will lead to failure of the tach gear is the distributor cross gear coupling. The cross gear will ride in the coupling and wear grooves in it. You should be able to hold the coupling up to a light and look through the hole. If you see grooves cut in there, this means the coupling has failed and it is cocking the gear which in return will eat up one or both gears.

Either way, you should inspect both before installing a new gear.


Willcox Inc.

 

Good information for us all. Thanks.

 

Can I piggyback off this thread?...

I'm trying to get the main shaft out of my tach drive and I cant get the tach drive threaded bolt to break loose. Someone said an *** screwdriver(what's that), is there anything else that will work and does that cable threaded bolt/nut have to come out to get the main shaft out? THX

 

I agree, Never, Ever, Ever, change the cross gear w/o changing the shaft, or you will just be buying a new cross gear.

 

Nevermind, got the nut out using screwdriver on one slot alone. Main shaft came right out.