Question About Six Volt System

[Speed]

Hi all;

I have a couple of electrical questions about my '45 EH. I posted these in General Discussion,but thought the electrical wizards might not have been there for a while.

My plan is to stick with my six volt system,running two big six volt batteries,but I'm wondering if I could use an SP switch to bring 12 volts to run an electric winch occasionally. As I understand them,the SP switch only provides double voltage for the starter in the "Start" position of the ingition switch;am I right? Well,first,is an SP switch voltage sensitive?Do I have to get one specifically for six to twelve,or would a 12 to 24 volt one work?

I'm not that good with electrics,so I'm asking-is there a way to have my six volt generator charge 2 six volt batteries and combine them "downstream" to run my truck on 12 volts?

I considered changing over to a GM internally regulated alternator,but decided I'd probably never find a pulley compatible with the inch wide V-belt,and besides-if it works right,no need to change it,right? So if there's no way to pull 12 volts for a CB,the winch,and some road lights,I'll figure out another way to go. The CB is no problem,but I think the rest of it will draw too much current to use a power inverter on. If push comes to shove,I really don't need any of that stuff, I can figure out other options.

I know this stuff isn't too big a priority for you guys,but I'm trying to get things figured out while I'm home,so when I go to Reno to start working on the I'll have my ideas,info and parts ready to go,so as to not waste time down there doing research and working out details to get things to work right.

Thanks for keeping up on my progress(?) and cheering me on.

Speed

[kevin mccune]

Many ways to do this-series paralell switches, switch it over to 12 volts- hard on the pinion or bendix&maybe the flywheel teeth-You can run the starter motor on 12 volts

(but it really will whiz) be careful when you mix batteries so you dont get a short(KWorths were a nightmare at times) you could mount a small 12V altenator to charge to charge a fairly large isolated battery to run your accesories.-You can charge 2 six volt batteries on your system easy if they are connected in paralell. Finally -you could mount a large 12V battery and charge it externally occasionally to power the 12V stuff and by large batteries I mean a group 4D or 8D and JC Whitney used to carry a 6V -S1 type altenator-By the way I do like old stuff old generators are pretty easy to keep going-Hope this is a little help and not too confusing-Kevin

[HK Trucking]

I would recommend switching it over to a 12 volt negative ground system.

Put a modern internally regulated alternator on it. (I'm sure a machine shop could fab a pulley for that wide belt).

Then you could easily & simply use your 12 volt winch, CB, Stereo etc. without complicated trouble prone circuitry.

Just be sure to install an ignition resistor in the supply wire to the ignition coil.

In the past I converted a pickup truck to 12 volts and continued to use the 6 volt starter, it cranked very fast, and was still working when I sold the truck a couple years later.

[ThaddeusW]

I would go with HK on this one, run a normal 12 volt negative ground system. You could run a s/p switch for 12 volt operation but it would be tricky to do. You could get 2 6 volt batteries Or 2 banks of 6v) and use the s/p switch to disconnect 1 battery from the 2 and put it in series for 12 volt accessories. One battery would be used for th rest of the truck while the second gives you 12 volts. The problem here is you wouldn't be able to charge the second battery while in 12 volt mode. After you turn the s/p switch off it would be put back in parallel with the other other 6 volt battery charging it.

Here is a diagram:

It works like this; the double pole double throw switch in the blue box switches the battery leads around. in the up position the batteries are in series and in the down position they are in parallel for charging and starting. You could use a manual switch but it would have to be rated for a few hundred amps.

[Speed]

I've run a six volt starter on 12 volts before too,and if you don't thrash it itll last a long while that way. Is there a 12 volt starter that'll fit this engine if I smoke the six volt one?

I'm thinking of looking into a PerTronix conversion for the ignition. That'll depend on how the truck runs,and whether there's one available for my distributor.

As far as the six volt or twelve volt issue,that'll depend on what it takes to make an alternator work on my engine. I remembered last night there's an accessory drive pulley on the harmonic balancer,so if it's anywhere close to a "normal" belt size I could probably run an alternator off it,along with my air compressor. I imagine the generator provides the belt adjustments for the fan/water pump,so I could replace the generator with the Alternator and install an idler/temsioner from something with a serpentine belt to provide the adjustment for the dual fanbelts.

The more I think about it,(and the more I search for,and don't find,6 volt accessories) converting to 12 volts would probably save me a bunch of troubles and money. I'd like to keep the charging system as original,but it really isn't practical in a truck that'll be used for work.

Thanks for getting me to think more clearly about what will be best for my in the REAL world.

Speed

[Speed]

I talked to my local electrical wizard yesterday,and he,and you guys,convinced me to go with a 100 amp alternator that's built for over the road trucks,because the big alternator is nearly a bolt on swap and my generator pulley will fit it. The price new from him is the same as it would be to build a 90 amp GM light truck/car alternator,which I'd have to do a lot of fabrication to install.I'm going for one large 12 volt battery mainly to simplify the electrics,and it'll carry the load fine. As near as I could tell,the wiring on the truck hasn't been butchered too much,so it should be good with the 12 volt conversion. I'm probably going to install an 80 amp fusible link off the main power lead from the alternator to protect the diodes should the wiring suddenly leak all the smoke out. (and carry a spare one in the tool box. ) So,the electrick will be handled.

After this part is done,all that will remain,electrically,will be reversing the leads at the ammeter,changing all the light bulbs,changing to a 12 volt coil and reversing its polarity,changing out the cigar lighter and getting resistors to drop voltage to the heater motor and gas gauge. The starter and horn can stay six volt and will work okay. Thanks for your input and wizdom,Thaddeus,HK,and Kevin;you guys have probably saved me from making an expensive and eventually problematic mistake. Back to the KISS system! (Keep It Simple,Stupid!)

Speed

[ThaddeusW]

Speed thats the best way to go. Keeping the 6 volt pos ground system would have driven you bananas because some winch motors don't have a ground terminal instead relying on the motors metal case as the ground. Also radios and CB's have allot of their internal components grounded to the metal case so isolating them from making contact with any metal in the truck would be a real pain. Last thing you need is your new CB or radio releasing the "magic smoke" and stop working.

[Greg Rider]

Hey Speed,sorry it's been a while,i've been busy working on my A-30 alot trying to get ready for a show next month.It's just little stuff but I want it all done and done right.I,ll try to give you some input on a few of your posts here.YES go with a 12 volt neg. ground system.Your starter will be fine as is.It will turn faster and easier on 12 than 6.Your engine will start much easier also.A Leece-Neville alternater should fit perfectly on your engine.That is what I did and I didn't have to change any brackets. Be sure to get a 12v regulater if you get an externally regulated unit.My truck had a 6v alt. and regulater on it,and I wanted to keep an original look,so I went with a 12v regulater that is a direct replacement.It looked identical to the 6v unit,even wired the same Switch the wires on the back of your Amp gauge,the gauge it self is safe because it is not voltage sensative.Change ALL of your bulbs and headlamps to 12v.Have fun with the little ones on the back of your speedo and 4 way gauge.PLEASE do not go cheap on a voltage reducer for the fuel gauge.I do NOT advise using the ceramic auto parts store units,and I have never heard any feedback on the "runts" type reducers that mount to the back of the gauge.I did quite a bit of studying on this and went with the VR-1 reducer from Ron Francis Wire Works.This is a very well built electronic unit that is a little bigger than a pack of cigarettes.It is a $40 unit but worth the insurance of not having a truck fire.The last thing to do is switch the wires on the coil and put a ballast resister on the POS side.You can get one of these at the parts store.If the parts store seems at a loss for words on which one to get, tell them it is for a '72 Chevy truck.Why not,because you probably have a Delco distributer anyways.I did my 12v change 8 years ago,everything has worked perfectly since then.

[Speed]

Hey Speed,sorry it's been a while,i've been busy working on my A-30 alot trying to get ready for a show next month.It's just little stuff but I want it all done and done right.I,ll try to give you some input on a few of your posts here.YES go with a 12 volt neg. ground system.Your starter will be fine as is.It will turn faster and easier on 12 than 6.Your engine will start much easier also.A Leece-Neville alternater should fit perfectly on your engine.That is what I did and I didn't have to change any brackets. Be sure to get a 12v regulater if you get an externally regulated unit.My truck had a 6v alt. and regulater on it,and I wanted to keep an original look,so I went with a 12v regulater that is a direct replacement.It looked identical to the 6v unit,even wired the same Switch the wires on the back of your Amp gauge,the gauge it self is safe because it is not voltage sensative.Change ALL of your bulbs and headlamps to 12v.Have fun with the little ones on the back of your speedo and 4 way gauge.PLEASE do not go cheap on a voltage reducer for the fuel gauge.I do NOT advise using the ceramic auto parts store units,and I have never heard any feedback on the "runts" type reducers that mount to the back of the gauge.I did quite a bit of studying on this and went with the VR-1 reducer from Ron Francis Wire Works.This is a very well built electronic unit that is a little bigger than a pack of cigarettes.It is a $40 unit but worth the insurance of not having a truck fire.The last thing to do is switch the wires on the coil and put a ballast resister on the POS side.You can get one of these at the parts store.If the parts store seems at a loss for words on which one to get, tell them it is for a '72 Chevy truck.Why not,because you probably have a Delco distributer anyways.I did my 12v change 8 years ago,everything has worked perfectly since then.

:thumb:Thanks Greg;

I did it pretty much as you said,but it turns out I was lucky-the previous owner had already done 90% of the conversion. I already had 12 volt lights,generator,electric fuel pump and gas gauge(it looks stock but is accurate),and I bypassed the Ammeter and went to an aftermarket volt meter because the ammeter only went to something like 60 amps,but my new internally regulated alternator is rated at 140 amps,and I don't need any magic smoke coming outta my dashboard. (And,BTW-the stock generator pulley DIDN'T fit-I had to special order one for 56 bucks)

I had my brother Dutch rewire the whole truck for me,and we ued a GM fuseblock,light switch and dimmer switch;I also changed the dashlights over to new style bulbs-much better!,and used a standard GMC horn. Now I also have a pair of air horns plumbed into a lanyard valve and an air tank,awaiting some kind of an air compressor. I just posted a question in these forums about a tach for my gas engine.

The coil was already swapped for 12 volt,with a built in Ballast (judging from the ceramic cap on one end of it)

So far,my only "problem" is the battery seems to be getting too good a charge-after a couple hundred miles I could smell that overcharging battery smell. I think a dual battery bank with GOOD quality

batteries will solve that problem. (I MIGHT have to run a bunch of clearance lights,too.)

Now,if I can get two of my brakes to quit dragging,and if I flush and re-fill the cooling system,and if I replace the input shaft seal on the Brown Lipe,and the pinion seal on the rear end,it'll be ready to roll.

Speed

[Rob]

:thumb:Thanks Greg;

I did it pretty much as you said,but it turns out I was lucky-the previous owner had already done 90% of the conversion. I already had 12 volt lights,generator,electric fuel pump and gas gauge(it looks stock but is accurate),and I bypassed the Ammeter and went to an aftermarket volt meter because the ammeter only went to something like 60 amps,but my new internally regulated alternator is rated at 140 amps,and I don't need any magic smoke coming outta my dashboard. (And,BTW-the stock generator pulley DIDN'T fit-I had to special order one for 56 bucks)

I had my brother Dutch rewire the whole truck for me,and we ued a GM fuseblock,light switch and dimmer switch;I also changed the dashlights over to new style bulbs-much better!,and used a standard GMC horn. Now I also have a pair of air horns plumbed into a lanyard valve and an air tank,awaiting some kind of an air compressor. I just posted a question in these forums about a tach for my gas engine.

The coil was already swapped for 12 volt,with a built in Ballast (judging from the ceramic cap on one end of it)

So far,my only "problem" is the battery seems to be getting too good a charge-after a couple hundred miles I could smell that overcharging battery smell. I think a dual battery bank with GOOD quality

batteries will solve that problem. (I MIGHT have to run a bunch of clearance lights,too.)

Now,if I can get two of my brakes to quit dragging,and if I flush and re-fill the cooling system,and if I replace the input shaft seal on the Brown Lipe,and the pinion seal on the rear end,it'll be ready to roll.

Speed

If you are smelling the sulfuric acid from overcharging, your regulator for the alternator is bad or needs adjusted. This was a common occurence and regular maintenance interval in a earlier time.

Ignition coils have either a primary resistance wire that is disconnected during the engine crank cycle, and enabled during the run cycle, or an external ballast resistor that follows the same theory. The purpose of a ballast resitor is to limit voltage to the breaker points to extend their service life. In normal operation, full battery voltage is applied to the ignition system during a crank cycle, and limited to an area between 9.25-9.75 volts when the engine is running. You can run full battery voltage all of the time, but the breaker points will not have a very long service life. If you do not have resistance wire in your cranking circuit, a Chrysler ballast resistor is easy to obtain at your local parts vendor, and easy to install.

Rob

[Greg Rider]

:thumb:Thanks Greg;

I did it pretty much as you said,but it turns out I was lucky-the previous owner had already done 90% of the conversion. I already had 12 volt lights,generator,electric fuel pump and gas gauge(it looks stock but is accurate),and I bypassed the Ammeter and went to an aftermarket volt meter because the ammeter only went to something like 60 amps,but my new internally regulated alternator is rated at 140 amps,and I don't need any magic smoke coming outta my dashboard. (And,BTW-the stock generator pulley DIDN'T fit-I had to special order one for 56 bucks)

I had my brother Dutch rewire the whole truck for me,and we ued a GM fuseblock,light switch and dimmer switch;I also changed the dashlights over to new style bulbs-much better!,and used a standard GMC horn. Now I also have a pair of air horns plumbed into a lanyard valve and an air tank,awaiting some kind of an air compressor. I just posted a question in these forums about a tach for my gas engine.

The coil was already swapped for 12 volt,with a built in Ballast (judging from the ceramic cap on one end of it)

So far,my only "problem" is the battery seems to be getting too good a charge-after a couple hundred miles I could smell that overcharging battery smell. I think a dual battery bank with GOOD quality

batteries will solve that problem. (I MIGHT have to run a bunch of clearance lights,too.)

Now,if I can get two of my brakes to quit dragging,and if I flush and re-fill the cooling system,and if I replace the input shaft seal on the Brown Lipe,and the pinion seal on the rear end,it'll be ready to roll.

Speed

[Greg Rider]

Hey Speed. The tachometer I run is a small unit that I mounted to the steering column with a clamp.It is just a cheap auto parts store unit that is about 2 1/2 in. round with a full housing.I put it at about the 1 o'clock position so I could see it through the wheel.It reads up to 8000 rpm which is very very optomistic for a flathead 6 Mack, but I put the red shift pointer at 3000.I don't look at it much as I listen to that sweet 6 and shift when needed.At first I would look just to see where my revs were and make sure I wasn't over revving,now I just glance at it for reference and assurance.I will try to get some pics in soon so everyone can see my low mileage beauty.

[Speed]

Hi Greg;

I'd like to see your truck. I see you rdline your engine at 3,000 rpm's-what rpm do you use for road speed on the highway? I believe my engine's strong enough to pull to 3,000 but I wouldn't run it that high for more than a moment. (I probably have,by accident,but I have no way of knowing for sure.) I'm guessing I could safely cruise it at around 2,700 or 2,800,but I really don't know.

I haven't had time to do much on my recently,I have an old GMC dumper I need to get in order soon for a couple of jobs,and my brother Dutch is building me a newer,bigger one ton duallie work truck as we speak,so I'm getting ready to drive my '62 Chevy one ton to Reno on the 10th,where we'll pull the engine,tranny and wheels and install them on the "new" truck,remove whatever else I think can be used by another '62 owner,and scrap the rest. (I hate the thought of scrapping it,but at least its heart(engine) will be beating in my next truck and other parts will keep a couple more '62's on the road. And I figure I should get about $125.00 for the rest of the truck as scrap.)

Once the new truck is ready to roll I'm buying a car hauler trailer for a friend up here in Elko,so I'll have to replace a tire on that,straighten an axle and wire the lights,brakes and a plug,load all my spares up,and haul a$$ for Elko.

Once that's handled I need to get the brakes done up on the ,flush its cooling system,replace the output shaft seal on the Brownie and the pinion seal on the rear end and work on getting trailer air set up on it so I can put IT to work. And in the spare time I never seem to have,I have one car to dis-assemble and 3 cars to re-assemble. By then Winter'll be here and I can start working on the inside of the house.

I guess I shoulda posted this as an update;seems like once I start writing,I have to tell it all. I forget that not too many people'll care what I'm doing. I dunno-I guess it's always kinda interesting to see what others do withTHEIR time off the clock.

Speed

BTW-check out the link to JC Whitney at the end of "Another Tach Question";it's a 12 volt neg. grd. tach that goes 0-4,000 rpm's,and it looks like there's a mounting cup for it available! WAY COOL!!

[Greg Rider]

Sorry it's been a while for a post, my home computer died and I'm waiting on a new disc.I will try to get some pics scanned at my moms house next time I see her.I replaced all the wiring from the cab back and put a relay/fuse panel under the seat.I left the original in place but I needed more than 6 fuses to be safe, and feel at ease with the extra lights added to the truck.I only wind her tight to 3000 rpm when I upshift just to give me time to get to the next gear without too much loss of speed.I cruise at 45 MPH around 2000 RPM and can go 50-55 at 2800-2900.I only run at 55 on the short stretch of highway I drive to get to the one show I attend.The truck seems fine at that speed.I've never had an overheat or drop in oil pressure.The only problem I have is a vibration right at 50 MPH that goes away above or below that speed.I think it is my carrier bearing or the u-joint right at the bearing.She just loves to run at 45! It would probably make it to the moon and back with a full load at 45,but only the NASA could afford the fuel bill!

[Greg Rider]

Speed,I finally got pics of Faith uploaded.They are in my gallery.The one pic shows her loaded with about 10,000lbs of hay.She ran great and went 45mph without a problem .Just road really nice and smooth!!!!!

[Speed]

Speed,I finally got pics of Faith uploaded.They are in my gallery.The one pic shows her loaded with about 10,000lbs of hay.She ran great and went 45mph without a problem .Just road really nice and smooth!!!!!

Hi Greg;

WOW-what a great looking rig!! You've done a great job with 'er!

I'm going to be doing some trailer pulling with mine in the next week or two;I was given a 40 foot 5th wheel RV trailer I need to take to my property,about 30 miles away. After that,there's 3 other trailers (two 45 foot flatbeds and a 44 foot reefer) I will need to move,but those will only be about 2 or 3 mile pulls. I'll have to loosen the slack adjusters to move them since I still don't have an air system in place. I discovered my truck wasn't exactly overheating when I drove it from Reno to Elko;turns out I have a bullet hole in my top radiator tank,poorly patched,that was leaking each time I put the truck under an extended hard pull. Guess I'll be pulling the radiator for a rebuild next spring. I can do that while I have it on blocks to do all the wheel cylinders.

Not 100% sure yet but I might be using the to load scrap onto a trailer. I'd like to be able to use the EH to pull the trailer to Reno or SLC and back,but I'm pretty sure it'd be too costly to get the truck up to legally proper condition to be cost effective. I'll still have chances to use my from time to time though.

Anyway,I sure like your truck,keep it rockin'!

Speed

[Speed]

BTW-I'm told the alternator I installed is set up to use an electronic tach like any newer Diesel would use,so it's just a matter of choosing one I like.

Speed