Help! Frustrated with tachometer repair

[bwstreaker]

I cannot get the tachometer in my 1968 to function properly and would appreciate help. I have the original gear drive tachometer in my vette which bounced at low RPMs. I checked the cable and it appears OK. The cable end is also not rounded. I have replaced the side distributor gear and installed an angled cable connector at the distributor so the cable is not bent. After all this, the tach simply bounces between 0 and 500RPMs even when engine speed is increased. What do I need to try next?

 

[tnovot]

I cannot get the tachometer in my 1968 to function properly and would appreciate help. I have the original gear drive tachometer in my vette which bounced at low RPMs. I checked the cable and it appears OK. The cable end is also not rounded. I have replaced the side distributor gear and installed an angled cable connector at the distributor so the cable is not bent. After all this, the tach simply bounces between 0 and 500RPMs even when engine speed is increased. What do I need to try next?

I assume you have already removed all old and/or hardened lube from the cable and relubed it with a high quality white lithium grease?

 

[bwstreaker]

Thanks for the reply tnovot. Yes I did put new grease on the cable. I am having trouble keeping the coupling holding the tach drive cross shaft gear tight in the distributor.

 

[GTR1999]

I have not rebuilt a tach drive distributor for several years now but the last two I did I found the quality of the new cross gears terrible- At BEST. These came with a brass button on the end and I was told I had file the button to set the gear lash, well that was total BS. I set it up in a lathe and face the button a few thousands and nothing helped, I removed the button made my own and had the same result, returned 3 of them all the same- junk. I found an old used GM cross gear and it worked perfect. you may be chasing your tail with bad parts.

 

[bwstreaker]

Gary, you might be right !! I have now put in two new gear sets with the same results. In neither case did I use the brass button and I thougyt that might be my problem. Ray

 

[GTR1999]

I can only guess the new ones haven't been corrected then, the ones I had and this goes back about 8 years or more, were clearly bad. The main shaft gears had issue too if I recall on the new ones I bought, but that brass tipped type would not engage without binding. I don't rebuild a lot of tach drive distributors but I do a lot of differentials, steering boxes, and arms and can tell you that some of the replacement parts for those are also bad. Luckily I have good resources and in the case of the boxes I have a huge inventory of new parts that do work.

 

[bwstreaker]

Thanks Gary!!
Ray

 

[Red89C4]

I went thru the "gear fitment" issue a short time back on my 72 Vette. The only complete repair I was able to accomplish was to send the O.E. distributor out to a vendor off Ebay. The price was cheap...less then $100 as I remember....and it was guaranteed and works fine now.

 

[bwstreaker]

Thanks for the reply Red89C4. I am to the point where I will probably do the same thing.