37-39 instrument question

gkgeiger

gkgeiger

Senior Member
I needed a temp gauge for my 39 and ended up buying a really nice complete set of 37 gauges. I'm in the process of changing them but ran into a small issue. My stock 39 ammeter has a metal bar running from a common positive terminal. My new 37 gauge doesn't have a threaded post but something different (see attached picture). I'm assuming I just make a jumper wire but have no idea what kind of terminal/connector to use on the gauge end. Does anyone have any help? Thanks in advance
37 ammeter
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39 gauges
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The more I think about this and look at the other gauge the more I think a jumper isn't going to work. The whole back of the gauge it brass, so if I connected a pos. feed to it it would go straight to ground (dead short). Now I'm really confused. Does some kind of insulated wire go thru that terminal?
 
Ford ammeters from 1933 through somewhere into the '50's used the inductive loop. I think your bus-bar connected gauge must be a voltmeter...
What does it say on it and how is it calibrated?
 
Hi Bruce,
Thanks for the response, you've helped me in the past. I just took another look at it and I believe you are correct. It says Batt. and the other says Amps. It reads L N and H. I think I'll put the 39 gauge in the 37 cluster. I like a volt meter better. I didn't realize they used them in that era.
 
Mine cluster looks like the picture of the back of yours... mine is a voltmeter, shows operating system volts rather than charging amps... Your single gauge picture is an amp meter... Voltmeter is what I prefer... There should be a bunch of them out there, and they're easier to hook up.
Karl
 
A length of wire runs through this loop, usually from the battery to the starter, the direction of current is important too because the meter is reading the direction of current, look at a wiring diagram for the year of gauges
 
The 39 gauge set you show is for a Deluxe car and is wired for a battery gauge not an ammeter. Only 39 Standards had ammeters. If all you need is a 39 temp gauge and you have a working 37 temp gauge why not just swap face plates, that's the only difference between the 37 and 39.
 
David W Juliano said:
The 39 gauge set you show is for a Deluxe car and is wired for a battery gauge not an ammeter. Only 39 Standards had ammeters. If all you need is a 39 temp gauge and you have a working 37 temp gauge why not just swap face plates, that's the only difference between the 37 and 39.
Click to expand...
Thanks to everyone who replied. Yes, I could have done what you said but the cluster I got was nearly perfect so I used everything but the voltmeter.
 
If you are going to use tha ammeter, obviously you need to look over diagram from an ammeter equipped car, but from memory I think you will just be lengthening the big feed wire from starter solenoid (I think) to your circuit breakers so it can run through the loop. Important high amperage wire, so do good job. The former voltmeter feed would be removed leaving the remaining links that feed other gauges hooked up.
 
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