68 Tacho cable quesstions
03-28-2015, 03:58 AM
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68 Tacho cable quesstions
Hi guys,
Got a SB 68 and having a few tacho issues.
When I got the car the tacho was not working, previous owner had installed a disti without the mechanical tech drive.
Recently I picked up a HEI with the mechanical tach drive, the aim was to swap and connect up the mech.
Turns out that.
1. the cable is broken, so will need a new tach cable.
2. the HEI has a square hole for the tacho cable, where as the cable on the car is a round keyed. (I didn't check this prior to ordering).
Haven't gotten around to removing the whole cable yet, was a plan for another day.
Questions for everyone.
What is the shape of the tacho cable that runs into the back of the tacho in the dash? Is it square or keyed?
Just trying to figure out since I need to replace the cable, can I get one that will fit the HEI, or do I just send the HEI back and go to plan B?
Help suggestions appreciated.
Cheers
Got a SB 68 and having a few tacho issues.
When I got the car the tacho was not working, previous owner had installed a disti without the mechanical tech drive.
Recently I picked up a HEI with the mechanical tach drive, the aim was to swap and connect up the mech.
Turns out that.
1. the cable is broken, so will need a new tach cable.
2. the HEI has a square hole for the tacho cable, where as the cable on the car is a round keyed. (I didn't check this prior to ordering).
Haven't gotten around to removing the whole cable yet, was a plan for another day.
Questions for everyone.
What is the shape of the tacho cable that runs into the back of the tacho in the dash? Is it square or keyed?
Just trying to figure out since I need to replace the cable, can I get one that will fit the HEI, or do I just send the HEI back and go to plan B?
Help suggestions appreciated.
Cheers
03-28-2015, 08:37 AM
#2
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Member Since: Aug 2006
Location: Jeffersonville Indiana 812-288-7103
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Hi guys,
Got a SB 68 and having a few tacho issues.
When I got the car the tacho was not working, previous owner had installed a disti without the mechanical tech drive.
Recently I picked up a HEI with the mechanical tach drive, the aim was to swap and connect up the mech.
Turns out that.
1. the cable is broken, so will need a new tach cable.
2. the HEI has a square hole for the tacho cable, where as the cable on the car is a round keyed. (I didn't check this prior to ordering).
Haven't gotten around to removing the whole cable yet, was a plan for another day.
Questions for everyone.
What is the shape of the tacho cable that runs into the back of the tacho in the dash? Is it square or keyed?
Just trying to figure out since I need to replace the cable, can I get one that will fit the HEI, or do I just send the HEI back and go to plan B?
Help suggestions appreciated.
Cheers
Got a SB 68 and having a few tacho issues.
When I got the car the tacho was not working, previous owner had installed a disti without the mechanical tech drive.
Recently I picked up a HEI with the mechanical tach drive, the aim was to swap and connect up the mech.
Turns out that.
1. the cable is broken, so will need a new tach cable.
2. the HEI has a square hole for the tacho cable, where as the cable on the car is a round keyed. (I didn't check this prior to ordering).
Haven't gotten around to removing the whole cable yet, was a plan for another day.
Questions for everyone.
What is the shape of the tacho cable that runs into the back of the tacho in the dash? Is it square or keyed?
Just trying to figure out since I need to replace the cable, can I get one that will fit the HEI, or do I just send the HEI back and go to plan B?
Help suggestions appreciated.
Cheers
We just installed the HEI tach drive distributor in our shop, once you have the distributor in place and aside from running a direct 12 volt switched power source, it's plug and play.
On all 68 cars, power to the coil runs through the porcelain resistor on the firewall (unlike 69 and newer cars) So for 68 you want to jumper power from the voltage input side of the porcelain resistor. Do not use the existing wire from the resistor to the coil! On 69 and newer cars you'd want to jumper power from the fuse panel.
68 drops the ignition voltage through the resistor, 69 and new drops it through the resistance wire... but the coil on the hei requires a sold 12 volts when running.
Willcox
Last edited by Willcox Corvette; 03-28-2015 at 08:41 AM.