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#1
01-31-2003, 05:45 PM
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I ask this in another forum some time ago but did not get a definitive answer. Maybe better posted here.
If going from a HEI ignition to a point type set up what needs to be done to get the tach hooked up since the point dist. does not have the plug in for the tach? Are there any other voltage issues? Phil  "dreamed I was wide awake........woke up and I was sound asleep"
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"dreamed I was wide awake........woke up and I was sound asleep" |
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#2
01-31-2003, 05:45 PM
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I ask this in another forum some time ago but did not get a definitive answer. Maybe better posted here.
If going from a HEI ignition to a point type set up what needs to be done to get the tach hooked up since the point dist. does not have the plug in for the tach? Are there any other voltage issues? Phil "dreamed I was wide awake........woke up and I was sound asleep"
__________________
"dreamed I was wide awake........woke up and I was sound asleep" |
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#3
01-31-2003, 05:57 PM
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The signal wire for the tach connects to the (-) side of the coil. If you have an OEM tach, the only other connection is ground. If you have an aftermarket tach, you will probably need to also connect to a switched power source (+12 when the key is in RUN position) and the same signal connection and ground (and panel lighting).
Regards, George
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"...out to my ol'55, I pulled away slowly, feeling so holy, god knows i was feeling alive"....written by Tom Wait from the Eagles' Live From The Forum |
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#4
01-31-2003, 06:08 PM
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Thanks George. The tach is the orig that came in the 70 T/A. Someone had put a hei dist in this T/A. Will the orig tach work with the hei and if so where does it hook up since the is no external coil now?
Phil "dreamed I was wide awake........woke up and I was sound asleep"
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"dreamed I was wide awake........woke up and I was sound asleep" |
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#5
01-31-2003, 06:59 PM
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Yeah it will work with hei, just attach wire to tach terminal in cap next to the power terminal. or negative on coil for points distributor.
 GR-RRR!
__________________
 1970 GTO 458 CID .040 over 4 Bolt 428 Block, Forged Eagle 455 Crank, 295 CFM SD KRE D-Ports, SD Old Faithful HR Cam + Comp HR Lifters, PPR Maxx-lite rods, Racetec pistons, PRW 1.65 SS Rockers, 900CFM Holley HP TBI, Performer RPM, Hooker Super Comps, 3" X-Pipe into 2.5" mufflers/tailpipes, 2.75 1st TH400, Continental 13" Converter, 8.5" 3.08 Posi. Everything installed, fired up and tuning has begun! |
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#6
01-31-2003, 10:49 PM
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I think you are wrong Mr. 428GTO70. I think the circuitry won't work on the newer upgrades unless tach has been updated also. I think it has to do with the way the tach "reads" the incoming info. (pulse vs. ???).
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So long, farewell. |
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#7
02-01-2003, 12:06 AM
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Really? I wasnt aware of that, you could be right. I thought a tach signal was a tach signal. Theres a pulse that goes up with rpms, i figured that would be the same. I Dunno? Ive never seen any listings for tachs with or without hei but I dont know. Anyone confirm this? I'd like to know for sure too.
GR-RRR!
__________________
1970 GTO 458 CID .040 over 4 Bolt 428 Block, Forged Eagle 455 Crank, 295 CFM SD KRE D-Ports, SD Old Faithful HR Cam + Comp HR Lifters, PPR Maxx-lite rods, Racetec pistons, PRW 1.65 SS Rockers, 900CFM Holley HP TBI, Performer RPM, Hooker Super Comps, 3" X-Pipe into 2.5" mufflers/tailpipes, 2.75 1st TH400, Continental 13" Converter, 8.5" 3.08 Posi. Everything installed, fired up and tuning has begun! |
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#8
02-01-2003, 01:08 AM
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It seemed to be all the same for me. I bought a tach & gauge cluster from a late 70's T/A, and hooked up the tach just fine to my standard distributor 73 engine after a little modification to my printed circuit. I bought a harness from a resto supplier, and it worked fine. It hooked up to the coil (-) for input signal, and used the +12v from the under dash fuse block. Gnd was just a dash screw. HEI or points style I don't think should really matter. If you stick a DC voltmeter on the tach plug (HEI) or at the coil neg term (points), you'll still get the same 0-14 volt reading that varies with engine rpm (inversely if I remember correctly).
"...ridge reamer and ring compressor? Do they have tools like that?"
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"...ridge reamer and ring compressor? Do they have tools like that?" |
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#9
02-01-2003, 01:08 AM
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It seemed to be all the same for me. I bought a tach & gauge cluster from a late 70's T/A, and hooked up the tach just fine to my standard distributor 73 engine after a little modification to my printed circuit. I bought a harness from a resto supplier, and it worked fine. It hooked up to the coil (-) for input signal, and used the +12v from the under dash fuse block. Gnd was just a dash screw. HEI or points style I don't think should really matter. If you stick a DC voltmeter on the tach plug (HEI) or at the coil neg term (points), you'll still get the same 0-14 volt reading that varies with engine rpm (inversely if I remember correctly).
"...ridge reamer and ring compressor? Do they have tools like that?"
__________________
"...ridge reamer and ring compressor? Do they have tools like that?" |
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#10
02-01-2003, 01:10 AM
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oops, double clicked.
"...ridge reamer and ring compressor? Do they have tools like that?"
__________________
"...ridge reamer and ring compressor? Do they have tools like that?" |
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#11
02-01-2003, 01:47 AM
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Squidward, you are talking about taking the new technology and getting it to work on the old. Not the other way around. I thought, as I understood it, tach technology changed in the way a tach "reads" the engine pulse. That is why new aftermarket tachometers work on any system.
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So long, farewell. |
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#12
02-01-2003, 04:46 AM
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I just figured that if A=B, then B=A. The pulse DC signal coming out of a distributor should be the same for either HEI or points style, shouldn't it? It worked for me to cross a tach used on an HEI system (originally) and a points ignition, so I wouldn't think there'd be any cross compatibility issues.
"...ridge reamer and ring compressor? Do they have tools like that?"
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"...ridge reamer and ring compressor? Do they have tools like that?" |
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#13
02-01-2003, 08:22 AM
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Looks I better wait awhile longer before hooking this tach up. Don't want to fry a brand new tach (restored). Any more thoughts on this guys?
Phil "dreamed I was wide awake........woke up and I was sound asleep"
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"dreamed I was wide awake........woke up and I was sound asleep" |
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#14
02-01-2003, 06:13 PM
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Philcol:
Listen to what George posted. Tach could care less whether its a points type or HEI type. All it sees is trigger that fires the coil "Suppose you were an idiot... And suppose you were a member of Congress... seems I repeated myself." --Mark Twain 
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Less said,,,,,,,, Less mended. |
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