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From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Need Tachometer Fix Feedback
The distributor on my 1968 SB car is a later model with the electronic output rather than the mechanical one. The tach is the original mechanical one and not working as the cable is just hanging near the distributor (right side of picture with bungee cord attached). There is no fitting on the tach end of the cable. As I currently understand I have two possible options to try to get this tach working again.
1. Replace the distributor with one that has the mechanical output. Will I need a new cable as well if a connector is missing? Likely have to take apart the dash which is not easy. Might be able to get to the back of the tach with the dash not out however the cable on this year car has a threaded connection rather than a clip. Would also need to remove the drivers seat to be able to get to all this.
2. Install an electrical to mechanical PCBA converter on the back of the tach. Definitely would have to take apart the dash and remove the tach to install. Also at the same time I can replace the not so clear front pieces on the tach and the speedo. Do not need to take out the drivers seat.
3. Change tachometer to later model replacement electrical input type. Would have to take apart the dash as well.
Any feedback, alternatives or suggestions are greatly appreciated.
Last edited by Redvette2; Apr 1, 2020 at 05:13 AM.
Reason: Added option 3 after getting feedback.
Just took my dash out on my 72 to do the electronic tacho conversion, I didn't take the seat out although it would have been easier for disconnecting the cables.
Once taking the dash pad off I had access to the cables from the top as well.
The biggest thing in the way from my experience was the steering column, I know people recommend completely dropping it out, I didn't do this I just dropped the two bolts and struggled with it a bit.
And yes if you were to go down the path of a tach drive dsitributor, from your photo you would need a cable as the threaded collar is gone which secures and locates it to the distributor.
The previous owner of my '73 installed an HEI distributor. He sourced a tach from a later model C3 (I think he said '75 but it's been too long to remember). He used the original face plate from the '73 so the conversion looked factory. It worked and was accurate. I've since converted to all Autometer gauges.
I converted my 68 to an electric tach. I bought a 76 tach from a member here and I bought a new tach board locally. It's been great and it works like a dream. My center gauges had already been converted to white lettering and I had replaced my speedo with white lettering so getting that 76 didn't make no never mind to me.
If I was doing it today, and wanted to keep the original faceplate, then I'd get one of these conversion kits..... costs about the same and it's modern. Mine has been great so I'm not complaining but this looks quite nifty....and these kits weren't available about 2003 (or I was not aware).
HINT- if you're going to pull the dash, then remove the steering column....makes everything a lot easier and you don't break things. I finally did it last time I pulled mine apart for relamping..... I should have been doing it all along.
Last edited by carriljc; Mar 25, 2020 at 09:56 PM.
The connector is missing from the distributor side cable sheath and you are missing the metal tip from the core. It is not too difficult to reach and work the screw-on connector on the tach just by reaching up behind the dash. It requires a little patience. I haven't tried snaking the sheath through the firewall, but how hard can it be?
first i would chuck cable end in a drill and spin it and see if and how well tach reads. the dist end is the same as the trans end from speedo cables of that era. might be able to scare up an old cable to steal an end from. or buy a new tach cable to remove the end from.
Just got an email from Zip Products and they now sell NEW 75-77 reproduction electric tachometers! This is amazing.... that's about what it cost me to buy a used tach and a new board...and that was years ago! https://www.zip-corvette.com/instant...31239292872963
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Very interesting...only $20 more than the conversion PCBA. Be my luck I get the old tach hooked up and then its 50 year old internals wouldn't work. Need to investigate if the 75 year part would definitely fit in a 1968 dash. You installed a replacement mechanical of this period and also the electrical PCBA right? No other mods?
I installed a 76 tach in place of my old mechanical tach. I had to replace the circuit board also since it did not work. Bolts right in place where the mechanical tach used to be.
Originally Posted by Redvette2
Very interesting...only $20 more than the conversion PCBA. Be my luck I get the old tach hooked up and then its 50 year old internals wouldn't work. Need to investigate if the 75 year part would definitely fit in a 1968 dash. You installed a replacement mechanical of this period and also the electrical PCBA right? No other mods?
first i would chuck cable end in a drill and spin it and see if and how well tach reads. the dist end is the same as the trans end from speedo cables of that era. might be able to scare up an old cable to steal an end from. or buy a new tach cable to remove the end from.
agree take dist end of core & chuck it into drill (IIRC use REVERSE) and test tach before you make a final decision. IIRC, a 600rpm drill motor should register 1200 rpm on tach but don't hold me to that tidbit.
Just got an email from Zip Products and they now sell NEW 75-77 reproduction electric tachometers! This is amazing.... that's about what it cost me to buy a used tach and a new board...and that was years ago! https://www.zip-corvette.com/instant...31239292872963
Zip also posted a video on how to fix tachometers and speedometers
Need Tachometer Fix Feedback
