Hi Guy's
I went out to the garage and pulled a box of gauges off the shelf. 2 set's
of gauges had ammeters the other 2 set's had an idiot light labeled
generator. All these gauges were for GMC TF. So this means you can go either
way and still stay sort of original. Just trying to help.
steve 55TF GMC
From: mark@noakes.com
Reply-To: mark@noakes.com
To: oletrucks@autox.team.net
Subject: Re: [oletrucks] Voltmeter or Ammeter, and Current
Date: Sun, 05 May 2002 08:08:58 -0700 (PDT)
Jim's commentary on this subject is better than mine. I agree with the
fusible link or
installation of a fuse in the ammeter circuit.
My 58 NAPCO will be straight stock but I can hide a fusible link in there
easily. My
Chevy Sub will absolutely have AC at least and I'd like to do a slight
upscale
radio/casette/CD player upgrade (original appearing radio, hidden
casette/CD, no
gigawatt amplifiers necessary), but I want to keep the stock gauges so I may
have to
innovate here. I'll probably put a fuse in the ammeter circuit and look at
adding an
extra couple of circuits for the aux stuff, hidden, of course.
This has been a good calibration for me; itl's important to understand what
people are
comfortable with. I work in close proximity with this stuff on a daily
basis, and it's
easy to take it for granted and to become complacent. Just got done this
last week
helping a mech engr coworker size a current shunt, and isolated voltage
amplifiers (one
millivolt for the current shunt and one higher voltage for the load) to
take data for a
high voltage fuel cell power generation test (for a robot, not a car).
Good luck whichever modification you choose and Jim's right; be careful.
Mark Noakes
58/56 Chevy Suburban, V8, 3-speed + OD
58 GMC NAPCO factory 4wd, 6 cyl, 4-speed, original power steering, wideside
(fleetside)
59 GMC Suburban
Knoxville,TN
On Sat, 04 May 2002, J Forbes wrote
>
> Hi all...
>
> On the "could they be stupid enough to run all that current thru a
> voltmeter" thread...yes, they ran all that current thru an AMMETER. But
> things changed a few years later, when they used an external shunt type
> ammeter (really a voltmeter) on the trucks, as on the 1964 model that I
> just worked on. With this setup, the meter just measures the voltage
> drop across the big wire which connects the battery to the rest of the
> truck wiring.
>
> If you read the Ron Francis ads (he has been making wiring harnesses for
> street rods for a long time), you'll see that others have the same
> concern about sending all that current thru the dash wiring. Chr*sl*r
> products used ammeters at full current up till sometime in the 70s, and
> often had wierd problems when the ammeter stopped working...such as the
> battery not charging, etc. The old Chevy ammeters are very reliable,
> though.
>
> In a perfect world, I replace the ammeter with an idiot light (connected
> to the brown wire on the alternator). This allows me to run the red
> underdash power feed wire straight out to the battery connection on the
> starter, where I install a fusible link. These modifications make the
> wiring more like newer GM cars/trucks, such as the 70s and 80s models.
> The late late model GMs have gone to big fuses for everything, there are
> 2 big fuse panels on my wife's 99 Silverado! one underhood, one
> underdash.
>
> The solution? If you are using the truck in a normal way, with no power
> robbing accessories such as killer stereos, A/C, funny lights, etc, then
> you can use the stock wiring. Make sure the terminals at the ammeter
> are tight, and that the nuts that hold the spades onto the ammeter are
> tight. It'll work fine, I've been running my orange 59 this way for 25
> years, with no wire smoke. It wouldn't hurt to add a fuse link (4 gage
> numbers smaller [bigger number = smaller wire] than the main feed wire,
> such as #16 link for the stock #12 feed wire) where the main power wire
> connects to the battery cable.
>
> If you are going to completely rewire the truck, using one of those
> aftermarket harnesses, then replace the ammeter with a piece of red
> translucent plastic, and put a light bulb behind it (some fabrication
> required). The light connects to the brown wire on the alternator, and
> the ignition switch wire. This lets you know when there's a problem,
> and lets you run the power feed wire safely without worrying about the
> voltage drop thru the ammeter and all that extra wiring. You can run a
> properly sized feed wire (number 10) and a properly sized fuse link
> (number 14), and all should be well.
>
> THat's my take...please be careful with wiring, it can be dangerous!
>
> Jim F
> 59s in AZ
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
_________________________________________________________________
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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