# Readers Respond

#### This Time the Discussion Ranges From a Favorite Car to Electronics Insight to Some Gas Station Memories.

**A 42-Year Involvement With a GTO**

**Editor’s note:** The following letter is in response to my recent Rearview Mirror column “Greeting an Old Friend.” I encouraged readers to have a leisurely visit with their favorite ride and get reacquainted prior to taking that first drive in the warmer springtime weather.

Ted – I read your April Rearview Mirror column and thought it was insightful and thought-provoking as usual. But I found myself running on a contrary path to your thoughts as I read your words and here’s why. Having owned my ’65 GTO since 1975 and seeing it go from daily driver status to being laid up in a garage waiting for a much-needed re-birth, to its current stage of life, a freshly (almost completed) driver, I realized that it’s not only the car that was reborn, but me also.

The interior isn’t finished and the car is wearing a coat of primer, but it’s a running, driving car once again and I vowed to take it out as much as possible through the winter (weather considered). I was fortunate to be able to get the car out at least once a week with only a few exceptions due to snow or heavy rain.

I found myself squarely in the scenario you laid out, experiencing a level of auto-nirvana when I’d enter the garage and uncover my pal’s nose, seeing those stacked headlights looking back at me. Once inside the car I also did as you mentioned, scanning the newly rebuilt dash panel, running my hands over the fresh three-spoke steering wheel and eying the oil pressure gauge with the gaze of an eagle when I’d fire the engine, watching to ensure all systems were “go.”

Easing off of the clutch pedal and pulling out of the garage feels like it did some 42 years ago, only better, and when I make it out to the main road and the Hurst stick finds 2nd gear via the new 5-speed transmission and the acceleration of the dual quad Poncho engine propels me down the road I can feel a clean 30 years washing off of my shoulders as I once again enjoy spending time with my old high school companion.

For me the season really never ended, it just got slowed down some, and I’m looking forward to another go-around of tweaking and making my longtime friend the best example of what I think an old car should be.

Thanks for awakening that feeling in your readers. Now it’s time to do that Spring oil change and give my pal a good bath and a shot of Windex to remove all traces of winter.

But first, here’s another interesting tidbit for you. When I called my wife out to see the engine run for the first time after I’d finished working on it, I caught her weeping. I asked if the engine was on fire (since I was inside the car watching the oil pressure), and when I realized it wasn’t I went to her to find out what was wrong. She told me that seeing the car run again made a movie replay in her mind; it encompassed me bringing the car home in its “less than grand” condition, working on it every day, coming into the house filthy dirty (but smiling), and keeping at it for four years. Then she remembered that when we started dating in 1979 I was driving the car daily so it had a history for her as well. She never thought it would see the light of day again and was happy to see me prove her wrong. (Wow, how often can a husband say that?!)

Since then, her and my kids have all exclaimed how phenomenal it is that one person could rip a car totally apart and build it back up again and be able to drive it. I’ve told them that they forget all the other project cars and bikes I’ve built because this one is just a little more special part of the family. Besides, how else could I justify all the tools and equipment I have sitting out in the garage?

Happy cruising…

**Ray Guarino MotorMouth Radio MotorMouthRadio.com**

**Editor’s note, continued:** Regular readers will recognize Ray as an ongoing contributor to these pages and co-host of the MotorMouth Radio Automotive Talk Show with car buddy Chris Switzer. You can catch their show live on 90.3 WHPC-FM broadcast from Long Island, New York, every Sunday and Thursday from noon to 1 p.m. Eastern Time or visit their website, motormouthradio.com, to hear archived broadcasts and for more on theguys and their program.

**Let’s Revisit That Discussion About Electronics**

In reading the discourse between Mr. Osstyn and the Mechanic on Duty, Mr. Richardson, regarding electrical questions and the size of wiring needed in the December 2016 issue of AR, I had a couple thoughts that “may” shed a bit more light.

First, the caveat. While spending a career as a wireman (electrician), I always say I think I’m one, until I start working on automotive projects or appliances. In which case, that always raises doubt in my mind.

Mr. Osstyn’s application of Ohm’s law is correct. While I didn’t spend the time to verify the wire’s resistance he estimated. In Mr. Osstyn’s application of Ohm’s law the calculation would be correct if it were hooked up as a direct short between the battery terminals of the different voltage batteries.

What was being missed in his analysis was the purpose of the wire which is to deliver the proper voltage to the starter, as well as being of a size (gauge) having the current carrying capacity sufficient for the load being served.

To properly operate a dual voltage motor, it will require twice the amperage if the voltage is cut in half. And along with that, a conductor with twice the current carrying capacity will be required for the lower voltage circuit. Or obviously vice versa.

I believe Mr. Richardson understood the information from his friend, but in stating the voltage/amperage relationship in the second paragraph I think it may have been a bit confusing to some. As Mr. Richardson stated, “watts” is the load or the work needing to be done. The Ohm’s law formulas where “watts” comes into the equation are as follow:

P (watts) = I (current) X E (voltage) P = I^2 X R *** I^2 is meant to signify I squared

P = E^2 / R *** E^2 is meant to signify E squared

Let’s look at an example. I believe the wattage of the headlamps in my ’72 Ranchero is ~ 60 watt lamps. Using the above noted formulas for 12-volt and 6-volt systems, with 60 watts being the work needing to be done.

12-volt system: P (60 watts) / E (12 volts) = I (5 amps) or I (5 amps) X V (12 volts) = P (60 watts)

6-Volt system: P (60 watts) / E (6 volts) = I (10 amps) or I (10 amps) X V (6 volts) = P (60 watts)

Generally speaking for domestic wiring, a 12-gauge wire is rated at 20 amps. Not sure what the SAE amperage ratings are for automotive wire. If the same—in the case of my Ranchero a 12-gauge wire has the current carrying capacity to serve all four of the headlamps. If the Ranchero had a 6-volt system with the same four 60-watt lamps, it would require two 12-gauge wires to serve the lighting load of the vehicle. Or one with twice the current carrying capacity which generally speaking in a domestic application would have to jump two sizes to an 8-gauge wire.

Now taking that a step further to calculate the resistance the circuit sees with a 12-volt lamp versus the 6-volt lamp, to prove out the increased resistance required, as stated by Mr. Richardson. Using the figures from the above noted calculations.

P = I^2 X R

12-volt system: P (60 watts) / I^2 (25 amps) = R (2.4 ohms) or I^2 (25 amps) X R (2.4 ohms) = P (60 watts)

6-volt system: P (60 watts) / I ^2 (100 amps = R (.6 ohms) or I^2 (100 amps) X R (.6hms) = P (60 watts)

It’s easy to get confused once calculations include the square of a value.

If simply calculating for amps: With a given resistance, a doubling in voltage produces a halving of amps.

Conversely when calculating for watts: With a given resistance, a halving of voltage rather than producing a halving of wattage, will in effect produce a quartering of wattage.

One more caveat. You must find the wattage of an incandescent lamp either by its marking or other means of looking it up. Using an ohm meter will not give you the resistance seen by the circuit. It takes someone smarter than me to explain why. I suspect the inaccuracy of an ohm meter reading may be a combination of factors. Such as the tungsten filament of the lamp having a positive temperature coefficient, meaning as the filament heats up the resistance increases.

**J.C. Blankenship Wenatchee, Washington**

Ted – I would like to finally respond to Jeff Osstyn’s question in the December 2016 Mechanic on Duty. The part that Jeff is missing is the rest of the circuit. His numbers would be correct if he were to connect one end of the wire to the positive post and the other end to the negative post. But this does not provide any useful work, unless the heat given off by the wire is considered useful. As Jim Richardson said in his response, the key is the amount of work to be done. In Jeff’s example, the work is provided by the starter motor, which is missing from his calculations.

Jeff stated the first part of Ohm’s law which is Voltage (volts) = Current (amps) X resistance (Ohms). Jim stated the second part of Ohm’s law which is Power (watts) = Voltage X Current. Simple algebraic manipulation will yield multiple variations of the two equations, but I’ll stick to the basics.

The standard conversion is 746 watts per horsepower and DC motors are about 63% efficient. Assuming a starter does one horsepower worth of work, we have 746 watts/.63 = 1184 watts for the electrical input to do the one-horsepower worth of work. From the American Electricians handbook, #4 American Wire Gauge (AWG) wire has 0.26 ohms per thousand feet while a #1/0 AWG wire has 0.10 ohms per thousand feet. Allowing for a total of 6 feet of wire to and from the starter, the resistance of a #4 AWG starter circuit is 0.0016 ohms and the #1/0 AWG circuit is 0.0006 ohms. Both of these resistances are negligible compared to the 1184 watts of the starter.

For the 6-volt system, 1184 watts divided by 6 volts = 197 amps. Jim stated that #1/0 wire is typically used for 6-volt starter circuits, so 197 amps x 0.0006 ohms gives a voltage of 0.12 volts. This means there is a 0.12 volt drop in the wire leaving 6 volts minus 0.12 volts = 5.88 volts available at the starter. Normally, a #4 wire would heat up too much with this type of current flow, but to illustrate the effect of voltage drop, it will be used here. Repeating the same calculation for #4 wire, 197 amps x 0.0016 gives a voltage drop of 0.32 volts, leaving 6 volts minus 0.32 volts or 5.68 volts available at the starter.

Now the above paragraph will be repeated for a 12-volt system, with the same 1184 watts divided by 12 volts to give 99 amps. For #1/0 wire, 99 amps x 0.0006 ohms gives .06 volts leaving 12 volts minus 0.06 volts or 11.94 volts available at the starter. For #4 wire, 99 amps x .0016 ohms gives 0.16 volts leaving 12 volts minus 0.16 volts or 11.84 volts at the starter. Jim stated that a #4 wire is typically used in a 12-volt system and as can be seen, a #4 will adequately do the job. It is cheaper than a #1/0 wire, so that is why it is used.

Wire sizes are rated for the amount of steady current flow they can conduct without overheating. Typically, the current flow is first determined by the load and then wire size is chosen based on the current flow. A starter circuit does not conduct current continuously, so the wire can be downsized somewhat because the wire has a chance to cool a little before the next crank of the starter. However, the same would not be true for a lighting circuit. The size should be sized for the continuous current flow.

**Walt Kiffer Dolan Springs, Arizona**

**Memories From My Grandfather’s Gas Station**

**Another Editor’s note:** In the October and November issues we talked about the lure of old-style gas stations that we knew decades ago. Readers have since shared some of their great gas station stories and memories with us, such as those in the following letter:

Ted – In the early 1950s my grandfather, Haskell Caldwell, and his partner, Lyle Moses, bought a Texaco station in downtown Hugo, Oklahoma, a small town in the southeastern part of the state. (Think horsemen and rodeos.)

Included are two photographs, one of the station and the other of my grandfather (left) and Lyle. No doubt you’ll take note of that tower behind the station. That was the cooling tower for an ice cream factory. Neither structure is there today. The gas station was gone sometime in the ’70s.

But even though the station had been sold by the time I was working on my cars, granddaddy would still help and guide me. One time he really chewed me out because I had grease above my wrist. He said there was no excuse for getting that messy. Today, with those photos hanging in my garage, I feel like he watches over me while I tinker on cars.

Further, I do remember granddaddy telling me that gasoline made the best parts cleaner but was illegal to use in the parts washer at the station, so they’d have to quickly drain it out if they heard an inspector was in town.

Prior to owning the filling station, he was head of repair for the local GM dealership. They would ride the train to Detroit and bring back several pickups, piggyback style. One year there was a strike and the angry men who were picketing wouldn’t let them pass. My granddaddy feared this might be the case, so he was prepared. He presented the leader of the strikers with a bottle of whiskey and told him these trucks were already sold and there were farmers and ranchers who needed these trucks so they could feed their families. The man let them pass.

Keep up the great magazine, I always learn something every issue!

**Charles Rahm Dallas, Texas**