Inaccurate reproduction speedometer
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2nd Gear
Joined: Nov 2020
Posts: 2
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Inaccurate reproduction speedometer
Hello,
I have a strange one . Frame off resto-mod on a 68 vert, Gages were faded and stained, so I ordered replacements from one of the normal vendors. The first speedo was in a GM marked box, and looked fine. 2 years later on fire up, on a lift with the wheels in the air, (TKO600 BTW) it immediately went to full scale and stayed there. Dead along with the Odo. Over the winter I bought a new speedo, again it shows up in a GM marked box, looks nice as did the first one. Installed along with new cables since I was there anyhow. Now $600 bucks in.
Well, this one works, sort of. The trip odo registers twice the value of the main odo, and at low speeds it reads 10 slow, and at interstate high speeds it is 20mph high. I can understand always being off one way or another, but not both. I have 250 miles on the recent speedo. Thoughts?
Thanks in advance. - Joe
I have a strange one . Frame off resto-mod on a 68 vert, Gages were faded and stained, so I ordered replacements from one of the normal vendors. The first speedo was in a GM marked box, and looked fine. 2 years later on fire up, on a lift with the wheels in the air, (TKO600 BTW) it immediately went to full scale and stayed there. Dead along with the Odo. Over the winter I bought a new speedo, again it shows up in a GM marked box, looks nice as did the first one. Installed along with new cables since I was there anyhow. Now $600 bucks in.
Well, this one works, sort of. The trip odo registers twice the value of the main odo, and at low speeds it reads 10 slow, and at interstate high speeds it is 20mph high. I can understand always being off one way or another, but not both. I have 250 miles on the recent speedo. Thoughts?
Thanks in advance. - Joe
Melting Slicks
Joined: Oct 2001
Posts: 2,065
Likes: 1,395
From: Halifax, Nova Scotia, Canada
Hello,
I have a strange one . Frame off resto-mod on a 68 vert, Gages were faded and stained, so I ordered replacements from one of the normal vendors. The first speedo was in a GM marked box, and looked fine. 2 years later on fire up, on a lift with the wheels in the air, (TKO600 BTW) it immediately went to full scale and stayed there. Dead along with the Odo. Over the winter I bought a new speedo, again it shows up in a GM marked box, looks nice as did the first one. Installed along with new cables since I was there anyhow. Now $600 bucks in.
Well, this one works, sort of. The trip odo registers twice the value of the main odo, and at low speeds it reads 10 slow, and at interstate high speeds it is 20mph high. I can understand always being off one way or another, but not both. I have 250 miles on the recent speedo. Thoughts?
Thanks in advance. - Joe
I have a strange one . Frame off resto-mod on a 68 vert, Gages were faded and stained, so I ordered replacements from one of the normal vendors. The first speedo was in a GM marked box, and looked fine. 2 years later on fire up, on a lift with the wheels in the air, (TKO600 BTW) it immediately went to full scale and stayed there. Dead along with the Odo. Over the winter I bought a new speedo, again it shows up in a GM marked box, looks nice as did the first one. Installed along with new cables since I was there anyhow. Now $600 bucks in.
Well, this one works, sort of. The trip odo registers twice the value of the main odo, and at low speeds it reads 10 slow, and at interstate high speeds it is 20mph high. I can understand always being off one way or another, but not both. I have 250 miles on the recent speedo. Thoughts?
Thanks in advance. - Joe
At this point I repaired my original speedo. It needed a new first gear (input with magnet) and a new second gear. Since the first gear came from another speedometer, I needed to calibrate the speedo. So far it's been working well for the past couple of years.
I tried to calibrate the warranty replacement speedo and there is not enough adjustment to make it accurate. I suspect the magnetism has faded, as the speedo MPH shows slow on calibration.
Last edited by Barry's70LT1; Jun 3, 2021 at 02:05 PM.
