Speedometer problem/conversion
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,160
Likes: 23
From: Prescott AZ
Speedometer problem/conversion
I have the original speedo in my 70 Vette but it has started to read high. Appears to be the speedo itself. I’m running a t56 magnum trani so I was wondering about going electric this time.
I want to keep it looking original.
I thought I remembered hearing about using a newer year electric speedo but not sure if that’s correct.
Any suggestions guy?
Thanks,
Rob
I want to keep it looking original.
I thought I remembered hearing about using a newer year electric speedo but not sure if that’s correct.
Any suggestions guy?
Thanks,
Rob
Pro
Joined: Sep 2017
Posts: 516
Likes: 72
From: Modesto California
I have the original speedo in my 70 Vette but it has started to read high. Appears to be the speedo itself. I’m running a t56 magnum trani so I was wondering about going electric this time.
I want to keep it looking original.
I thought I remembered hearing about using a newer year electric speedo but not sure if that’s correct.
Any suggestions guy?
Thanks,
Rob
I want to keep it looking original.
I thought I remembered hearing about using a newer year electric speedo but not sure if that’s correct.
Any suggestions guy?
Thanks,
Rob
I have heard electric speedometers are available for our C3's that look exactly like the OEM speedometers. Try calling Instrument Sales And Service and ask about them.
Melting Slicks
Joined: Jul 2010
Posts: 3,174
Likes: 631
From: perth western australia
all the speedo's in the c3 were cable driven,
it was the tacho that went from cable to electric .
This is the factory history , no doubt there is aftermarket things to get where you want .
So you Magnum has a cable drive on it now ?
it was the tacho that went from cable to electric .
This is the factory history , no doubt there is aftermarket things to get where you want .
So you Magnum has a cable drive on it now ?
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,160
Likes: 23
From: Prescott AZ
Used to be right on.
I’ve pulled the cable, checked and lubed it and checked the drive gear so figure it must be the speedometer itself.
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,160
Likes: 23
From: Prescott AZ
As I stated I’ve pulled the speedo cable and gear, checked and lubed them and it didn’t change anything.
I havent altered the car in any way in the last 3 years. Same tires, etc.
What else could it be?
Melting Slicks
Joined: Jul 2010
Posts: 3,174
Likes: 631
From: perth western australia
Have you taken the cable off the back of the speedo head unit and checked to see if there's any oil from the gearbox in it ? I say this as I have heard of oil getting (pumped or wicked ) up a cable ? Sounds crazy I know
If your after originality and you have verified its not the cable or drive/driven gears . Then maybe the quickest fix is to get your unit overhauled or get another one that is known to be ok.
Last edited by bazza77; Oct 17, 2017 at 03:12 PM. Reason: pushed the wrong key!
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,160
Likes: 23
From: Prescott AZ
Did the problem start after you lubed it ? I ruined one on my 77 when I helpfully sprayed the internals with wd40 !!!! but it didn't just read high, the needle just started bouncing all over the place
Have you taken the cable off the back of the speedo head unit and checked to see if there's any oil from the gearbox in it ? I say this as I have heard of oil getting (pumped or wicked ) up a cable ? Sounds crazy I know
If your after originality and you have verified its not the cable or drive/driven gears . Then maybe the quickest fix is to get your unit overhauled or get another one that is known to be ok.
Have you taken the cable off the back of the speedo head unit and checked to see if there's any oil from the gearbox in it ? I say this as I have heard of oil getting (pumped or wicked ) up a cable ? Sounds crazy I know
If your after originality and you have verified its not the cable or drive/driven gears . Then maybe the quickest fix is to get your unit overhauled or get another one that is known to be ok.
I didn’t check the back of the speedo but do know there was no trani fluid on the cable.
It reads high at all speeds but doesn’t bounce, it’s steady.
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Melting Slicks
Joined: Jul 2010
Posts: 3,174
Likes: 631
From: perth western australia
I didn’t do anything before it started acting up. I pulled the cable and inspected only in an attempt to find the problem.
I didn’t check the back of the speedo but do know there was no trani fluid on the cable.
It reads high at all speeds but doesn’t bounce, it’s steady.
I didn’t check the back of the speedo but do know there was no trani fluid on the cable.
It reads high at all speeds but doesn’t bounce, it’s steady.
Maybe get hold of Willcox ,or check his site out as they have lots of trouble shooting vids on there.
Apart from loosing the mileage read out , changing the whole unit isn't that bad a job.