Tachometer Cable
Thread Starter
Instructor
Joined: Dec 2006
Posts: 132
Likes: 0
From: Virginia Beach, VA
Tachometer Cable
I just got myself a 90 degree adaptor for my '71 bacause my tachometer jumps. But if I attach the adaptor the cable needs to go another way around some of the other wires and it becomes too short, then. I can see from Corvette America that the length of a new cable is 22 inches. Is that the standard length? Or do you have other advice on how to solve this problem? - I want to keep the original mechanical tachometer.
Thanks.
Thanks.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Why did you buy the 90 deg. adapter, if the cable fit OK before you installed it [and won't now]? It's possible that someone [prior to your ownership] moved the distributor around a couple of spots to have less stress on the cable. Check the position of your #1 plug wire on the distributor and check the AIM for original distributor position and #1 wire position. You will need to put the dist. back to original state for the 90 deg. adapter to work as intended, if it had been changed. Otherwise, I don't know why you are having this problem.
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
i know one thing that is a fact,about the speedo cable,, you have to install the cable with the least 90's---i had it nicely laced inplace with tie wraps and it jumped like you describe, once i came from trans,,,angle over to heat shield area and straight up it stopped jumping,,as far as the tach did you look at the tack drive gear? there must be a 4 dollar thrust washer installed for the gear to ride against, i blew 4 drives before i figured it out, those gears go against each other and need that washer or the gears blow,,,finally after figuring it out i dumped it anyway for a msd tach drive dist..6al box and no more wet dist cap/moisture /dying
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
i know one thing that is a fact,about the speedo cable,, you have to install the cable with the least 90's---i had it nicely laced inplace with tie wraps and it jumped like you describe, once i came from trans,,,angle over to heat shield area and straight up it stopped jumping,,as far as the tach did you look at the tack drive gear? there must be a 4 dollar thrust washer installed for the gear to ride against, i blew 4 drives before i figured it out, those gears go against each other and need that washer or the gears blow,,,finally after figuring it out i dumped it anyway for a msd tach drive dist..6al box and no more wet dist cap/moisture /dying
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
R&I the dist ... clock it so the cable has least deflection ... that IS what GM tsb specified ... many years ago. Then, deploy the adapter as a paperweight.
-edit-heck ya don't even have to pull the dist ... just relocate the pwires on cap as you rotate dist.
-edit-heck ya don't even have to pull the dist ... just relocate the pwires on cap as you rotate dist.
Last edited by jackson; Mar 18, 2007 at 10:34 AM.
