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#1
03-27-2018, 09:22 PM
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tach testing
I have 3 62-64 full size tachs. Is there any way to check them besides on a running motor?
__________________
 Mike McCarty You can drop the line, but you'll never kill the spirit!Pump gas 535 w/Marcella cv/1's. 11.0 compression, 4000 stall, 3.73 gears, 275 radial, to the axle exhaust, 3470# w/driver. 9.49 @ 140..........so far |
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#2
03-28-2018, 02:30 AM
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Yes.
The tach will need [a] 12v + supply to it & [b] hooked up to the coil -ve terminal. |
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#3
03-28-2018, 04:16 AM
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Hello
I would go to a speedometer shop ... and have them checked for accuracy ..
I have a couple nos hood tachs .... 1 reads perfect to 5000 then every 1000 loses 400 rpm .... 1 reads fine to 3000 then falls on its face another works fine thru the rpm but is off by 700 after 1500 or hook up a good quality tach along side yours on your buddys old car and compare em best at the shop .... they should be able to give you a read out every 500 rpm on each Scott is this guy close to you ? https://www.bobsspeedometer.com/1/120/index.asp |
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#4
03-28-2018, 05:33 PM
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Post #2 is connected to a running engine. Sorry if that was unclear.
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#5
03-28-2018, 06:53 PM
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The tach will probably have a ground connection/terminal if it has a plastic case.
If the case is metal, the case should be grounded. |
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#6
03-29-2018, 02:17 AM
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Find a friend with an audio generator with square wave output option. Add a single-transistor NPN amplifier stage having its output zener regulated to 12 volts. Use this 12v square wave to bench-test the tachometer. Just do the math for what frequency to use for a given RPM. [Example: a V8 at 6,000 RPM would be a 400 Hz signal]
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Anybody else on this planet campaign a M/T hemi Pontiac for eleven seasons? ... or has built a record breaking DOHC hemi four cylinder Pontiac? ... or has driven a couple laps of Nuerburgring with Tri-Power Pontiac power?(back in 1967) |
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#7
03-30-2018, 11:23 AM
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Quote:
__________________
Mike McCarty You can drop the line, but you'll never kill the spirit!Pump gas 535 w/Marcella cv/1's. 11.0 compression, 4000 stall, 3.73 gears, 275 radial, to the axle exhaust, 3470# w/driver. 9.49 @ 140..........so far |
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#8
03-30-2018, 11:28 AM
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Thank you all for the replies.
__________________
Mike McCarty You can drop the line, but you'll never kill the spirit!Pump gas 535 w/Marcella cv/1's. 11.0 compression, 4000 stall, 3.73 gears, 275 radial, to the axle exhaust, 3470# w/driver. 9.49 @ 140..........so far |
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