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#86319 04/15/2004 2:30 AM | Joined: May 2003 Posts: 53 Member | | Member Joined: May 2003 Posts: 53 | My 1955 GMC 500 has the factory tach and transmitter on the firewall I need a wiring diagram for this unit. Any help will be appreciated Thanks Biddaboy :confused: :confused: :confused:
1956 GMC TF 1/2 ton
1955 GMC 500 model (Gumby)
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#86320 04/15/2004 11:19 AM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | Could it be a Sun made tach? or is it AC. If it's a Sun, you need only 4 wires. The back of the tach has a positive and negative terminals which go the the same marked terminals on the transmitter. Take a good know ground, directly from the engine is possible, connect that the transmitter ground. The remaining wire goes from the transmitter terminal marked dist., take that to the distributer side of the coil, not the ignition side. | | |
#86321 04/15/2004 9:36 PM | Joined: Feb 2004 Posts: 29,771 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,771 | Does the transmitter look like a big voltage regulator? If so, there are a couple of Mercury-cell batteries inside that power the transmitter. I remember those from back in the 50's and early 60's when Sun had the electric tach market pretty well sewed up. Good units, but those batteries had to be replaced pretty often!
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
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#86322 04/15/2004 9:55 PM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | Jerry ,those batteries are made out of unobtanium these days. I had my vintage Sun tach and transmitter converted to solid state by Williamson Gauge. | | |
#86323 04/16/2004 1:45 AM | Joined: Feb 2004 Posts: 29,771 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,771 | Kinda thought so! They were scarce and pricey 40 years ago! When the Sun SuperTach came out, it obsoleted the earlier-type tach with the transmitter, as I remember. It was one of the first solid-state tachometers on the market.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
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#86324 04/16/2004 4:10 AM | Joined: Feb 2003 Posts: 129 Shop Shark | | Shop Shark Joined: Feb 2003 Posts: 129 | I have a diagram for a Sun EB7A that I can email or go to the link in my signature and I will post the diagram.
My sun tach is in place and doesn't work well, one day it will read 2500 rpm at 55 mph and the next day it will read 3200 rpm at 55 mph. I have been told this is what to expect from a sun tach and the solid state conversion is the way to go.
Truckedup are you happy with the solid state conversion? I received a price quote from Williamson's of $180 including shipping handling to convert my sun tach. | | |
#86325 04/16/2004 10:59 AM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | Blaine, Williamson's did a fine job, the tach works ,well just like a new one, very smooth and steady needle movement. I remember paying about 140 bucks last year, and that was nearly 100 bucks less than other Sun Tach restorers.They gut the transmitter, encapsulate in solid state parts.Williamson's told me of a simple test for the tach head,briefly touch the leads from a single flashlight battery to the + and - terminals of the head,if the needle goes to high scale, the head is worth saving.
Your tach may need the adjustment done to hold the RPM steady.There points inside you can adjust. | | |
#86326 04/16/2004 2:58 PM | Joined: Feb 2003 Posts: 129 Shop Shark | | Shop Shark Joined: Feb 2003 Posts: 129 | I have adjusted the points and the needle is steady, just different from day to day.
I think next fall I will send my tach to Williamson's for an update.
I really, really like the look of the tach in the dash and it would be nice if it functioned as well.
What's ANOTHER $180! | | |
#86327 04/21/2004 6:09 PM | Joined: Jan 2004 Posts: 112 'Bolter | | 'Bolter Joined: Jan 2004 Posts: 112 | Do you have a link for Williamson Gauge? Can't find them on "Google"
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#86328 04/25/2004 3:09 AM | Joined: Feb 2003 Posts: 129 Shop Shark | | Shop Shark Joined: Feb 2003 Posts: 129 | | | |
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