The tach in my '66 works...but not very well...fluctuates wildly. Any thoughts on what I can do to fix it...is it strictly an electrical hook up?

Can anyone recommend a tach restoration person/service that they've been happy with?

Thanks.

Strickly electrical... One wire to the fuse box "ignition"(pink), one to the coil negative (brown), one tothe fuse box "light" (gray) and one wire to a good ground (black)...

Make sure the connections are good, tight and clean, especially the ground...

IF you solve the fluctuation, but the RPMs are off, there is a small screw in the back that can be turn to calibrate the RPMs (need to remove the guage from the chrome cup)...

Wow, thanks for the quick response!

Well,

I checked all the wiring to the tach and even pulled the tach out of it's holder...and there's no small adjustment screw?

I did remove and reseat the ground wire, though. The tach isn't jumping around like it was...but is for sure not very accurate! Were they ever really accurate? Right now, it says that I'm shifting at 6000rpm, which is definitely NOT the case....

Opinions/help?

Thanks.

Have an original 66 tack and it runs a little high. I've check a few places and the cost to fix is around $185-200 plus shipping. And they make it so you can run it with the original points distributor or a HEI.

Question for 1966 L78: How do I get the guage out of the chrome cup without caushing any damage to the ring and cup? Thanks, Jim

My thoughts are this... if one has a KK Tach that is not working.. in this day and age, I would not spend the money to have it fixed.. why? The Repros are about $189.00 and as far as Repro stuff goes, they are pretty darn good, almost impossible for the casual observer to see any diffs. esp. if just peering in the door looking at your interior.


As for pulling the tach guts out of the cup, if I read this correctly. There is a small screw on the bottom of the cup, just remove it. unclip the wires from the fuse box and pull the gauge out of the cup, no need to remove the cup from the dash. You will need to take the clips off the wires or it will not feed through though the cup hole.

Hope that helps.

Mike

Yes but taking the chrome bezel off the face of the tach is touchy since you have to bend back the tangs to remove bezel and they can break !! to redo the tach you need to remove the bezel ........I would like to know who repairs/ modifies these KK tachs to work with a magnetic pickup ignition ??

Had my 66 speedo rebuilt by www.gaugeguys.com their in Blomington mn, so far, so good. They do the tacks. Also talked to a guy from NC or SC, www.tackman.com/gm.htm Sounds like a good guy, hates those repo's made in Mexico. Think both do the modification so it can be used on both points and HEI,

Previous tackman address wrong use this one

My thoughts are this... if one has a KK Tach that is not working.. in this day and age, I would not spend the money to have it fixed.. why? The Repros are about $189.00 and as far as Repro stuff goes, they are pretty darn good, almost impossible for the casual observer to see any diffs. esp. if just peering in the door looking at your interior.


As for pulling the tach guts out of the cup, if I read this correctly. There is a small screw on the bottom of the cup, just remove it. unclip the wires from the fuse box and pull the gauge out of the cup, no need to remove the cup from the dash. You will need to take the clips off the wires or it will not feed through though the cup hole.

Hope that helps.

Mike


Mike,
Thanks for your help....My question is were these tachs ever really that accurate? It's not like I'm going to glance down before every shift:)

If my tach doesn't have this little adjustment screw like the above poster mentioned...is it a repro? How would I tell?

BTW, I PM'ed you!

Yes but taking the chrome bezel off the face of the tach is touchy since you have to bend back the tangs to remove bezel and they can break !! to redo the tach you need to remove the bezel ........I would like to know who repairs/ modifies these KK tachs to work with a magnetic pickup ignition ??


For the removal/adjustment/calibration, no need to remove the bezel... For re-silkscreening it does need to be removed... I had/have several bezels that are ruined because those tangs break off... I think the rings are the same as other GM guages of the era (442 vacuum gages, tachs, etc)...

There is even a Buick Wildcat tach that is almost identical to the knee-knocker (the chrome cut is identical except a slight contour where it meets the dash). The face is different...

Not sure about "magnetic" triggers, but the standard Knee-knocker will work with HEI (tach output) without modification to the tach (wiring connector at the distributor is all)...

I agree with Mike on the repro tach... On anything short of a concours full resto, I'd considering using the repro...


As for the "calibration" screw, its on the back of the tach... Remove that one screw and pull the tach from the chrome housing (that can stay attached to the dash)... as long as the wires can be pulled out. I held the tach in my hand, so the positive wire doesn't "arc". The screw is next to the wiring, and recessed in a hole. I think the hole might have been covered with tape.

I had one tach that I thought was "dead"... Turned the screw and it worked...

Thanks Tony...I'll check it out soon. Thanks for the tips on the wiring. I looked for that adjustment screw for a while...I'll have to look again.

DO the repro tachs have that screw, also?

Well I've got the pink, brown, and gray wires; but no black, maybe that's why every once and a while the tack stops working: there is a post with a nut on it that looks as if it could be for a round wire. ALSO there is no adjustment screw on the back, just pulled it out, everything on the outside and the face says it's a 66 kk tack. Does this mean someone just put a different tack in a the appropriate face on it? Or is there no adjustment screw on a 66 tack?