Electric tach problems

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Electric tach problems

Postby jbjaz » Tue Feb 17, 2009 5:04 pm

I made up an electric tach for my bugeye from a '65 positive ground tach movement. I also have another positive ground tach from a '65. I cannot get either tach to work right on my bugeye!!!.

I have wired it with looping wire from ING to COIL input, Spade lug to HOT, and grounded the case properly. One tach moves VERY solwly up to about 1500 at idle....sometimes. Theother doesn't move at all.

Any ideas?

Jim
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Re: Electric tach problems

Postby spritenut » Wed Feb 18, 2009 10:20 pm

First, is the Bugeye positive ground? If so, OK, if not, rewire the tach to negative ground.
You have to swap the resistor and the spade terminal wire from inside.
On the slow tach, it may be a bad ground or it needs an adjustment.
There is an adjustable potentiometer inside the housing, usually yellow, sometimes red, What you have to do is take the guts out of the housing and hook it all back up to the car, there is a screw driver slot in the potentiometer, slowly turn the slot a little each way and watch the needle move.
A tach/dwell meter will help you get it set perfect or you can set it up close by eye/ear.
I find that running a clean fresh ground wire from the housing to the chassis helps with bouncy or intermittent tach reading.
That little loop on the mounting stud just doesn't cut it.
Frank Clarici
Toms River, NJ
The BETTER not BIGGER Healeys
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Re: Electric tach problems

Postby jbjaz » Thu Feb 19, 2009 10:19 am

Thanks Frank,

Yes, the car is positive ground. I will try making a better case ground and making adjustments.I have a dwell tachometer for this (which works fine)

Also, I have an aftermarket coil (intermotor)....could this be the culprit? Or could it be the condenser? Seems strange that 2 tachs just don't work. Car runs fine so I believe that the ignition is in good shape.

I pulled the tach from my positive ground '65...which was working...and get nothing when hooked to this car....odd.

Jim
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Re: Electric tach problems

Postby jbjaz » Thu Feb 19, 2009 8:17 pm

More info:

Looks like the 1st tach (the one with slow movement) may have a bad, mechanically damaged movement.
The 2nd tach fom the '65 was converted to neg ground. I converted it back and it works now! BUT, it's reading about 2X RPM that it should. Is this just calibration, or is a component bad?

Thanks,
Jim
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