Speedometer question?
Thread Starter
Cruising
Joined: Nov 2004
Posts: 10
Likes: 0
Speedometer question?
I apologize upfront for my lack of "mechanical-ness", but I have a 1958 with a 350 engine. The speedometer/tachometer doesn't work. Would this be due to the engine (something along the lines of mechanical connections vs. electrical connections) or is my gauge busted?
Tech Contributor
Joined: May 2005
Posts: 15,575
Likes: 118
From: Conroe Texas
Assuming your gauges are the stock type...
Speedometer operates from a speedometer cable which is connected to the transmission. If the speedometer doesn't work, it could be:
1) The speedometer is broken
2) The cable is broken or missing
3) The plastic driven gear in teh side of the transmission is broken or missing
4) The metal drive gear inside the transmission is broken or missing.
You can check the cable and speedometer by removing the cable from the transmission, and connecting a power drill to the cable. You can then operate the drill, turning the cable, to see if the speedometer works. The drill should be operated in reverse (counterclockwise)
The metal gear turns the plastic driven gear, which turns the speedo cable, which operates the speedometer.
Tachometer operates, I believe, from a tach cable connected to the back of the generator. If the tachometer doesn't work, it could be:
1) The tach is broken
2) The tach cable is broken or missing
3) The generator gears that drive the tach cable are broken or missing.
Jeff
Speedometer operates from a speedometer cable which is connected to the transmission. If the speedometer doesn't work, it could be:
1) The speedometer is broken
2) The cable is broken or missing
3) The plastic driven gear in teh side of the transmission is broken or missing
4) The metal drive gear inside the transmission is broken or missing.
You can check the cable and speedometer by removing the cable from the transmission, and connecting a power drill to the cable. You can then operate the drill, turning the cable, to see if the speedometer works. The drill should be operated in reverse (counterclockwise)
The metal gear turns the plastic driven gear, which turns the speedo cable, which operates the speedometer.
Tachometer operates, I believe, from a tach cable connected to the back of the generator. If the tachometer doesn't work, it could be:
1) The tach is broken
2) The tach cable is broken or missing
3) The generator gears that drive the tach cable are broken or missing.
Jeff
Burning Brakes
Joined: Jan 2006
Posts: 844
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From: Westminster Maryland
St. Jude Donor '08
Tech Contributor
Joined: May 2005
Posts: 15,575
Likes: 118
From: Conroe Texas
Jack's post reminded me of one other item....
Tachometers that were made to work off of a generator originally, will operate off a distributor too, but will be inaccurate by a factor of 2 unless recalibrated.
Tachometers that were made to work off of a generator originally, will operate off a distributor too, but will be inaccurate by a factor of 2 unless recalibrated.
Thread Starter
Cruising
Joined: Nov 2004
Posts: 10
Likes: 0
Thanks everyone. I'll check the cable in the am. I have noticed it making a lot of noise lately inside of the speedometer (like grinding gears) and the needle likes to be either at 0 or 100mph, so it does flop around.
