66340SEDAN
FABO Member #3649
I have a few mechanical tachs made by Jones/Moroso...how can I bench test them to see if they work? I have cables for them....seeing that they have no electrical parts, how can I test them out? Thanks :glasses7:
How to test a Mechanical Tachometer or "Tach Drive"
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A damn good question..... I have no clue.
67Dart273
Well-Known Member
Pretty simple if you have a distributor to drive them You can drive the distributor with a drill, and use the points or magnetic trigger to produce pulses which you can figure RPM from and check against the tach.
http://www.forabodiesonly.com/mopar/showthread.php?p=1969578221#post1969578221
Otherwise, you need to round up somebody with a distributor machine, unfortunately mine is still apart!!!!
Also you need to determine if the tach is what is called a 2:1 or 4:1. "Most" driven directly off the cam or directly off a distributor are 2:1
I used to run a Jones-Motrola (it is not Motorola) in my '70 It was installed behind the bezel where the "tic tock tach" should have been
http://www.forabodiesonly.com/mopar/showthread.php?p=1969578221#post1969578221
Otherwise, you need to round up somebody with a distributor machine, unfortunately mine is still apart!!!!
Also you need to determine if the tach is what is called a 2:1 or 4:1. "Most" driven directly off the cam or directly off a distributor are 2:1
I used to run a Jones-Motrola (it is not Motorola) in my '70 It was installed behind the bezel where the "tic tock tach" should have been
66340SEDAN
FABO Member #3649
Thanks Del, my drill is a little smaller than the distributor shaft so that won't work. I tried hooking the cable to the tach, then the other end of it to the drill, then spun the drill but not much happened, maybe the drill spins too slow?
67Dart273
Well-Known Member
Make sure it's going the correct direction. Even a slow drill, or,,, even just "flipping" the dist shaft by hand should bump the needle. Get down to basics. Make sure the cable actually turns
What is the distributor? You have an engine you can plug it into?
So far as your drill, "rig" it, LOL. You DO know how to "rig" doncha?
maybe a 1/4 bolt, a connector nut (long nut) and a short scrap of 1/2? hose and a hose clamp?
See? easy LOL
What is the distributor? You have an engine you can plug it into?
So far as your drill, "rig" it, LOL. You DO know how to "rig" doncha?
maybe a 1/4 bolt, a connector nut (long nut) and a short scrap of 1/2? hose and a hose clamp?
See? easy LOL
ssba
Well-Known Member
Doesn't require much speed to move the needle. But you do have to turn it the right direction to get the needle to move. Once you have it spinning watch for a stable needle and listen for
bad noises. They are reliable pieces for the most part. I have bought 8 or so over the years and never got a bad one which is easily done with the electrics. One other thing to watch for is the cables on different mechanical tachometers use different ends. They just need to be compatible cable end and tach input.
bad noises. They are reliable pieces for the most part. I have bought 8 or so over the years and never got a bad one which is easily done with the electrics. One other thing to watch for is the cables on different mechanical tachometers use different ends. They just need to be compatible cable end and tach input.
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