Mechanical tach cable
Thread Starter
Drifting
Joined: Dec 2002
Posts: 1,887
Likes: 1
From: Hill AFB area Utah
Mechanical tach cable
On my 74 vette the tach cable is bad surprise, have never changed one whats the easiest way to do it any hints and tips would be greatly appreciated. Thanks 
Pro
Joined: Mar 2004
Posts: 686
Likes: 0
From: Southeast
Was easy in that question? 
I had my driver's side dash off, so it wasn't too bad. If you have really small hands, you might be able to put it in the back of the tach without moving the dash forward a little. It was kind of hard getting the new end on the distributor too, but the job overall isn't that bad. Good luck.
I had my driver's side dash off, so it wasn't too bad. If you have really small hands, you might be able to put it in the back of the tach without moving the dash forward a little. It was kind of hard getting the new end on the distributor too, but the job overall isn't that bad. Good luck.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Your biggest problem will be lack of space behind the dash. You need to be sure the square end of the new tach cable seats securely in the back of the tach before you button things up.
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
I hope you're not too big!
The cable attacment to the back of the tach involves sliding under the dash and seeing if you can get your hand up in there. Getting the cable through the firewall was easier than replacing the grommet that protects it.
Gary
The cable attacment to the back of the tach involves sliding under the dash and seeing if you can get your hand up in there. Getting the cable through the firewall was easier than replacing the grommet that protects it.
Gary
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
Where is your tach cable broken at? At the tachometer, or at the distributor. The tach cable is similar to a electrical coax cable. There is a thick outer cable skin, with the steel cable inside of it.
If you can turn the cable, and the tach moves then the problem may be at the distributor side. On my 73 I thought I had to replace the tach cable also. But I found out that the part where the cable goes into the distributor was broken. Before I replaced the entire cable, I bought a repair kit and used the square end piece to crimp to the cable, and it fixed the problem. I did not replace the cable, I only replaced the tip of it.
( NOTE: before doing this you should check that the cross drive gear in the distributor and the main shaft are not worn.)
Here is a shot of the replacement.
If you can turn the cable, and the tach moves then the problem may be at the distributor side. On my 73 I thought I had to replace the tach cable also. But I found out that the part where the cable goes into the distributor was broken. Before I replaced the entire cable, I bought a repair kit and used the square end piece to crimp to the cable, and it fixed the problem. I did not replace the cable, I only replaced the tip of it.
( NOTE: before doing this you should check that the cross drive gear in the distributor and the main shaft are not worn.)
Here is a shot of the replacement.
Thread Starter
Drifting
Joined: Dec 2002
Posts: 1,887
Likes: 1
From: Hill AFB area Utah
it is broken at the distro end. the inner portion is bad. however there is alot of junk inside so I will just replace the whole thing with the 90* adapter to keep this from happening again
East bound and down...
Joined: Dec 2004
Posts: 987
Likes: 3
From: Jonesboro Arkansas
Of course you could just give up and do away with the mech tach and update your tach to the 75-77 style. If your luck runs like mine, after I replaced the cable I had to replace the cross shaft and main gear. I said "goodbye" to having more metal shavings floating around in my motor somewhere and I had Mike Mercury convert my 70 tach to electronic.
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Burning Brakes
Joined: Jul 2000
Posts: 963
Likes: 0
From: melbourne,Australia
Originally Posted by dmrodco
On my 74 vette the tach cable is bad surprise, have never changed one whats the easiest way to do it any hints and tips would be greatly appreciated. Thanks
