The Stovebolt Site Forums The Shop Area The Electrical Bay 216 to 235 Electrical system question

Hello, I have a 1947 1/2 ton Chevy 3100 with a 216 engine in it. I’m in the process of swapping in a 1955 Chevy 2nd series 235 engine that is 12 volts already. I have a couple of electrical questions maybe you can help me with.
I need to purchase a new starter, So should I get a 1947 12 volt or 6 volt since I am using the 216 flywheel?
I also need too purchase a wire harness, the 55, 235 has a 12 volt generator but I want to install a alternator eventually. should I get a harness with alternator or generator connections?
What else would I need to complete this electrical?
Thanks guys

Since you need a new starter, buy a 12v conversion starter such as this one [Click] from Classic Parts.

If your wiring harness is in decent shape, you can make the change over to an alternator with a few wiring changes, otherwise you can purchase harness made for 12v and alternator’s from most vendors.

You’ll need to change all of the light bulbs including your headlights. A quick search using Google will find many articles and videos on how to change from 6 to 12 volts such as this one [Click].

This change has been made by many of the members here on the “Stovebolt” forums so if you run into any obstacles just ask!

Check our Tech Tips for a 12 volt conversion how to. You will need to stay with the 6 volt starter or a converted 6 volt starter unless you change the flywheel.🛠

Thanks for the info guys. I will get the 12volt starter and wire harness for alternator.
Is there a way to test my 6volt starter? I don’t have fancy electrical tools, I have a light tester, digital multimeter (not that I know how to use it lol) and jumper cables. Thanks guys

A 6 volt starter will work fine on 12 volts, just don't lay on it.

Ed

As said, the 6 volt starter is used on 12V here all the time. Keep it. Spend the money on a AC Delco 10si alternator and buy the alternator harness.
The time to switch to alternator is now. Do you know about the bypass/ballast resistor and coil and all that, for 12V? You need those parts also. The wiring sounds complicated, but it's not. We will help along the way. Lots of experience here on Stovebolt. Also, if you have a foot start, you may need to change the push button saddle switch, on top of the starter, to a side post style.

Have your 6 volt starter checked out by a starter rebuild shop. Have it rebuilt if it needs it. They work wonderfully on 12 volts! Turns the engine over very fast which results in quick starts.
Here's another benefit. If you should develop a somewhat discharged 12 volt battery for whatever reason, it will still turn over the 6 volt starter. A twelve volt starter, not so much.

Thanks guy this is great info. I wish I had read the last 2 post yesterday though. I would have rebuilt my starter, instead I ordered the 12 volt conversion and battery cables.
For the 12 volt system do I need to run the ground cable from engine to frame also or to the bell housing to the battery negative for the ground?
I don’t know all about the bypass/ballet resistor. Is that to lower voltage to the gages? I know the 235 I got came with a 12 volt coil, distributor, and generator because it was a 12 volt truck it came out of.
Is this a complete parts list to complete the 12 volt conversion?
Wire harness with alternator hook up
12volt battery
AC Delco alternator
12volt Coil resister ( I already have a 12volt coil)
Horn relay
All lights
Fuel gage reducer
3 voltage reducers for accessories ( heater and radio)
Am I missing anything or something I don’t need?
Thanks a ton guys

1. You need to ground everything to everything. You can go from battery to starter then braid strap to body and braid strap from body to frame....or any combo.

2. Ballast resistor is a ceramic block bolted to fire wall. Wire from ignition on to one end, other end to coil positive. DO YOU HAVE A FOOT START? This is necessary for us to know so we can complete the ignition wiring description. If you have an electromagnetic solenoid, the wiring is different than foot start.

3. There is no such thing as a 12volt coil resistor. You need a coil that says it is an externally resisted coil. Some coils are internally resisted but you are using a ballast resistor. That is the external resistor. the ballast resistor is for the points not gauges. You do need voltage reducers for fuel gauge, radio and heater motor. Read the tech tip on Stovebolt for 12V conversion.

4. All lights? you mean 12V bulbs and sealed beams.

5. Search a little on here using the search function to read all you can on ballast resistors and 12V conversion.

What harness brand and part number are you planning on getting so we can google it. Do you have a horn relay?

Thanks bartamos
I do have a foot starter, 12volt conversion starter, battery cables so far.
All lights 12volt. As for the harness I’m thinking of classic parts p/n 52-022 $149.50 or Jim Carter EL169 $215. Any suggestions on the harness to use? No I don’t have a horn relay yet, I haven’t purchased anything electrical yet besides starter and battery cables.
I need a alternator also I know it’s a AC Delco, but not sure which one to get. Some guys say 1 wire others say 2 wires! 🤔 will the alternator have a 5/8 pully?

Buy a GM 10-SI alternator. 1 wire or 3 wire is your preference. 1 wire style is easier to wire obviously but does have some drawbacks. Google “1 wire vs 3 wire alternators” and you will get many articles to help make your decision.

The biggest difference, in my opinion, is you can’t install an idiot light. I have a 1 wire alternator and while testing some electrical systems I have inadvertently left the ignition on and came back to a truck that would not start. I burnt out the coil and the points. If I had that idiot light, chances are I would have noticed the ignition was still on before I left the truck.

You may be able to buy an alternator with a 5/8” pulley but I had to change mine. I bought the pulley from Speedway. Easy to change, just use an impact to remove and install.

You will also need a new bracket to mount the alternator. I bought mine from The Car and Truck Shop and it needed a minor alteration to fit. The slotted holes were slightly smaller than the 3/8” bolts that attached it to the engine block. I sure you can buy one that fits.You will also need the bolt that attaches the alternator to the bracket.

You will need to change the switch that the foot start engages on top of the starter that has a small side terminal to apply 12v direct to the coil when in the start position only, rest of time coil is fed through ballast resistor. Stock GM part, someone here will probably have PN.

Ed

You can buy one at Classic Parts

There are three basic types of harnesses.
1. Specifically designed for your truck with original motor. It has the original style cloth covering and terminals. No fuses
2. Designed for your era of truck with modern wire and insulation. Like the one at Classic you mention. No fuses. Unknown number of circuits.
3. Universal harness with prewired ATC fuse panel, 12 circuit. Like
This one.
The universal harnesses all use the same quality wire. The prices are determined by number of circuits and extras and profit margins.

The older trucks did not have fuses much. Time to fix that with the kit no. 3. 12 circuits should be enough unless you have a bunch of accessories. I recommend the Speedway harness or equivalent prewired fuse panel type. If you need more circuits move to the Speedway 22 circuit @$189.

You will need to crimp various terminal contacts onto the ends of the harness wires as you route them to their connections and cut to length. We will help you sort it all out when you are ready.

Alternator. "3" Wire hook up.

Horn relay with screw terminals, much better than spade style.

The foot switch that Phil linked is what you need. . The Ignition switch is wired, as I said, to the ballast resistor on the fire wall, thru the resistor and to the coil positive. This gives the points a reduced voltage of about 9V so they last a long time. The starter takes a lot of voltage from battery during cranking and steals voltage from the points which are already only getting 9V. Soooooooooo....this side terminal foot switch, when foot switch is pushed, "bypasses" the resistor and gives the points as much voltage as possible during start. When you lift your foot as motor fires, the side terminal is shut off and the resistor takes over. The side terminal has a wire from it to the coil positive. So, two wires on coil positive.

Ignition switch usually gets it's power from a wire from the starter stud.

Cool thanks guys. I received my 12volt conversion starter today. I’ll be ordering the starter switch w/side terminal, horn relay, ballast resistor and the alternator you posted in the link. It really doesn’t mention the specs? Not a bad price either. I ordered the speedway universal 12 circuit wire harness. thanks again for sharing your knowledge with us newbies

Don’t forget you will need a new bracket to mount your alternator such as this. [Link]

63 Amps. Was not suggesting where to buy, just giving example and part number to search. Some are rebuilt, this said new.

Ok thanks. I received my wire harness from speedway the other day. Still waiting on the ignition switch, resistor, starter switch and horn relay, before I continue. I ordered a alternator, ACDelco P/N 335-1093. 63 amps, connection position @ 3:00 O’clock. Hope it’s the correct one! I think I’ll make my own alternator mounting bracket I have tons of scrap laying around.
Would I be able to use the spark plug cables from the 216 on the 235 since I already purchased them?
If you guys see I’m missing something please let me know, thank you

Sorry to jump in here so late, and the point is probably moot, but for those playing along at home and considering doing this themselves ... Can we walk this back to the beginning for a moment (indulge me) and somebody tell me why we are converting to 12 volts? Most of the time, it strikes me that the 12-volt conversion project is a solution in search of a valid problem. "Because the engine was 12 volts already" is not a valid reason in my mind. To that, I answer, "So what???" Engines are not 6 volt or 12 volts or anything electrical. They are engines -- the peripherals attached are what make them 6 or 12 volt. We make them one or the other because we *want* to, not because someone is holding a knife to our throats.

Not too long ago, I upgraded my '49 from it's original 216 to a 261 ... and kept it 6 volt. The hardest part (relatively speaking ...) was switching the flywheel ring gear from the 216 flywheel to the 261's flywheel (which DJ did for me and demonstrated just how easy that is to do). Other than that,*everything* else except for the manifolds transferred nicely to the 261 (even the distributor! Although you do have to be careful about what gear material is on the bottom end of that 216 dizzy...) and I didn't have the hassle of worrying about wire harnesses, ballast resisters, gas tank sending units, alternators (and bracket mountings) starter gymnastics, et al. I realize I am oversimplifying, but I do so to make a point ....

.... you *don't* HAVE to convert to 12 volts if you don't want/need to. And in a lot of cases, like mine for example, it's a whole lot easier and less expensive to stay 6 volts than going crazy with the 12-volt conversion. And staying 6 volts gives you a truck that is less hacked up and every bit as usable as a 12-volt truck. I live quite happily with 6 volts. Want easy starting? Most times, merely tuning your engine/adjusting your valves/using good gas will do the trick. Want a radio? Try an ipod or bluetooth speakers for your smart phone. Brighter headlights? Make sure your grounds are clean and tight -- my lights are as bright as anyone elses.

As I recall, in my engine upgrade, the only thing for the actual install (the engine rebuild is a whole other matter and you can read about it in the Tech Tips ) I had to order was the ... NOTHING. I had everything onhand already from my 216. AND the truck, was staying 6 volts, so I didn't have to disturb the wiring.

And I was fortunate enough to have been given a '54 mold 261 (Thanks AGAIN, Scott!!), so I didn't have to move the water pump or the radiator.

Bottom line -- Converting to 12 volts isn't a "must do" just because you are switching to a newer engine. People should put their wrenches down for a moment to consider their options against their wants and desires before following the herd into something that's expensive, time consuming and quite possibly *needless.*

After considering all this and you still want to convert to 12 volts, by all means go and do it. There are some advantages to being 12 volts (I can't think of any, but I'm sure there are some ... )

Hmmmm, this sound like a good tech tip -- "Things you don't have to do just because everyone else thinks its a good idea....."

Hope that helps ... someone ...

John

Adding to John's comments; my 6V truck starts just fine Thank You Very Much. Even down into the 'teens. And I do love how the starter with it's foot actuation sounds and I like the distinctive 6 volt horn sound. I do have modern quality, as in bright headlights thanks to a couple relays (I know, I copped out but when acquired, my truck had been rewired with a new harness and the wiring is sized for 12 volts, undersized for 6 volt systems).

Concerning a radio, my solution was one of these.. I did make one additional modern concession and that was 6 volt LED taillights. These things are Bright and I feel added a significant safety factor to the rear of the truck. Even with bright sunlight shining directly on the tail lights you can see how they're lit up with the LEDs.


RonR

ditto ditto ditto

As a minor aside/aspect of this let-it-be as it was born-as desire/attitude (except for a change to another newer/bigger stovebolt engine):

If you need a USB charger for low-power-draw modern devices (phone, GPS, radio, ear-phones, radio, . . .), supposedly, USB adapter for the 6v lighter socket charges those USB-plugged devices?

Has anyone tried a USB adapter like this?

Oh yeah, I also own (and often carry on long trips in all vehicles) a high-power portable 12vDC/120vAC/USB portable power station/supply.

It cost a lot, but it has proven to be useful on old truck trips, camping trips, parties on the beach, and jump-starting cars/trucks with dying batteries.

While we're on this topic, can someone explain to me what a "12 Volt Conversion Starter" is? 6V starters have a 5/8" diameter armature shaft, a straight spline where the starter drive engages the armature shaft, and a drive gear that's compatible with a 139 tooth flywheel. A 12V starter (1955 2nd. series and newer) has a shaft that's 1/2" in diameter, spiral drive lugs for the starter drive, and a gear that fits a 168 tooth flywheel. Is there some sort of hybrid of these two starters that combines features of both of them? It would appear to be difficult, if not impossible to do anything more than put a set of 12 volt field coils in a 6 volt housing. I'm not sure how effective, or even desirable it would be to do that.
Jerry

That’s what I’ve had done to several over the years. I guess someone is doing this commercially now days. Mine were done by old time starter shops, same with generators.🛠

OK, so it's basically a half conversion. Since most field coils are in series with the armature, the "conversion" would reduce the current draw slightly by using a higher resistance field. We used to call those "high torque" starters when a custom rebuilder would go the other way- - - -putting 6V fields in 12V starters for high compression race engines.
Jerry

You’re absolutely right about a engine not being 6 or 12volt, it is what you want it to be. As for my 47, I pretty much have a blank canvas because all I have is a shell of a truck. No electrical harness of any kind. With that being said. I want my 47 to have more modern electrical system. That’s why I’m going to 12volt. I know 6volt works perfectly fine, I just personally prefer a 12 volt since I have to purchase a wire harness anyway. Thanks

The 12volt conversion starter as far as I know.(after calling to ask) is just a 12 volt starter geared for a 216 fly wheel. Not sure about the fields. I got it from classic parts

Most likely you are correct - but, it would be nice if they state that it works with the 1955st and earlier 6v flywheel?

If you bought/have a 6v harness, those thicker gauge wires would nicely with a 12v conversion.

However, a 12v harness has wires that are too "thin" for use in a 6v system.

So now us 12V guys have to go underground. Cognito. Special Ops. Live in a closet......again. That's another story, never mind.

?? Who is asking 12v-converters to go underground?