Feeling so completely lost.

[xciter101]

Hello everyone. Looking forward to learning and sharing here as I embark on what maybe a very long project. I'm the excited and somewhat frightened new owner of a 1990 Chevrolet full size school bus, by Thomas. It has the 8.2 GM Diesel and AT.
I got a very good deal but I'm missing a lot of information and hope to fill in some blanks with your help.
My first issue is figuring out my voltage requirement. The batteries were removed but I have two jumpers, each with 3 side post style terminals and then the 2 leads that go inside.
My math tells me that 4 batteries are needed. Is this a 48 volt system? I also have no ignition key so I am looking for some schematics in order to use a universal switch that I already have.
Any info will be greatly appreciated.
Post Script Note: I do trust that this bus was running when my family friend parked it about 10 years ago but I am really anxious to verify this. LOL
Thanks


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[bigskypc50]

Greetings! Looks like you have a heck of a project there! What's your plans for the bus? I am no expert on anything but I have never heard of or seen a 48V system, most I have herd of is 24V. I doubt it's 24V, I would assume someone had 3 or 4 very small 12v batteries wired together in parallel to give you the CCA (cold cranking amps) for a diesel.

With something sitting for 10 years you would need to do a total swap of all of your fuilds, fuel, oil, coolant, trans and check the condition of the rear end pumpkin fuild. What kind of brakes? Wet type will likely need wheel cylinders The wheel bearing seals will likely need to be replaced and I would be suspect of the major seals.

I hope your good deal was almost free, thats a lot stuff to take on before you even convert it.

Not trying to scare you off but trying to realistic, I have dealt with a lot of cars that sat that long and you might be better off finding something fresher.

[xciter101]

Originally Posted by bigskypc50

Greetings! Looks like you have a heck of a project there! What's your plans for the bus? I am no expert on anything but I have never heard of or seen a 48V system, most I have herd of is 24V. I doubt it's 24V, I would assume someone had 3 or 4 very small 12v batteries wired together in parallel to give you the CCA (cold cranking amps) for a diesel.

With something sitting for 10 years you would need to do a total swap of all of your fuilds, fuel, oil, coolant, trans and check the condition of the rear end pumpkin fuild. What kind of brakes? Wet type will likely need wheel cylinders The wheel bearing seals will likely need to be replaced and I would be suspect of the major seals.

I hope your good deal was almost free, thats a lot stuff to take on before you even convert it.

Not trying to scare you off but trying to realistic, I have dealt with a lot of cars that sat that long and you might be better off finding something fresher.

Thanks for the info and I was really expecting 24 volt, with two big batteries, until I started counting terminals. And these look to be a factory set of jumpers. (Maybe not factory for this bus but not sure.)
I really did get a good deal (including an RV that will likely supply many donar parts for this build) and I'm used to handling most of the mechanical issues you've mentioned, just on a smaller scale. It does have wet brakes that are working at this point with minimal leaks, but yes I will need wheel cylinders and some flushing before I put anyone in danger.
I know very little about diesels though but do have some friends that will probably help drink beer and fire her up once I have the power and ignition switch taken care of.
My plans are to make this into a fair weather camper/RV for a few years and not sure after that. Seeing some of these builds from other members makes me want to sell my house and travel the country in a skoolie. It already has been cleared of seats and has insulation and subfloor in place but not glued down yet.

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[Brad_SwiftFur]

I am not aware of any school buses that ran on 24 volt systems (at least in the U.S.) I'm willing to bet it's a 12 volt system, the batteries wired in parallel.

[chev49]

When I added batteries, I went to the recycle yard and found two long copper bars. I built a box big enough for 6 truck batteries, drilled holes in the big copper bars and insulated them, and hooked the batteries up. By wiring correctly one can have extra or switchable bus batteries as well as inverter connections, etc

[xciter101]

I'm feeling bad about the title of my thread, but worse about not realizing this sooner.
The jumpers I mentioned are indeed made to wire in parallel.
There is a jumper with 3 (+) and a separate jumper with 3 (-)
so what I have here is set up for 4 batteries in parallel.
Again, my first expectation was 24 Volt, (2 12s in series) when I saw the jumpers crammed in the box. My only other multi battery setup prior to this was a 24V Kaiser M715, so I had flashbacks. LOL Then I counted the terminals in my head, while trying to sleep with visions of awesome skoolies in a caravan toward the west coast, and came up with 4 batteries.
Kinda threw me for a loop.

So, now, how many CCAs do I need to turn this 8.2 over,
and I'm about to google this, but how do you calculate multiple batteries' CCA to equal the actual CCA being supplied to the ignition? Really hoping I can do this with 2 batteries, rather than 4.

Originally Posted by Brad_SwiftFur

I am not aware of any school buses that ran on 24 volt systems (at least in the U.S.) I'm willing to bet it's a 12 volt system, the batteries wired in parallel.

[xciter101]

I am a scrap yard junkie by birth, I guess. You said copper bars and my hair stood on end. I love that idea but actually have so much spare welder cable and terminals available that I'd have to hold off on looking for bars...for now.

[EastCoastCB]

I'll bet one g31 would start it just fine.
Two would surely do the job.
IDK why anyone would need 4.

[xciter101]

I now understand that you were also leaning at parallel and 12 Volts.
I believe you were correct, as I now see my jumpers are designed for parallel, not series wiring as I first assumed.
Thanks again!

Originally Posted by xciter101

Thanks for the info and I was really expecting 24 volt, with two big batteries, until I started counting terminals. And these look to be a factory set of jumpers. (Maybe not factory for this bus but not sure.)
I really did get a good deal (including an RV that will likely supply many donar parts for this build) and I'm used to handling most of the mechanical issues you've mentioned, just on a smaller scale. It does have wet brakes that are working at this point with minimal leaks, but yes I will need wheel cylinders and some flushing before I put anyone in danger.
I know very little about diesels though but do have some friends that will probably help drink beer and fire her up once I have the power and ignition switch taken care of.
My plans are to make this into a fair weather camper/RV for a few years and not sure after that. Seeing some of these builds from other members makes me want to sell my house and travel the country in a skoolie. It already has been cleared of seats and has insulation and subfloor in place but not glued down yet.

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[xciter101]

While I'm definitely new to a diesel engine, I tend to agree.
Would you all definitely recommend a deep cycle specifically?
Will my bus' charging system charge 2 marine batteries effectively or would I need to trickle it often?
I'm just relieved that it appears to be a 12 Volt system.

Originally Posted by EastCoastCB

I'll bet one g31 would start it just fine.
Two would surely do the job.
IDK why anyone would need 4.

[turf]

like eastcoast said, 2 group 31, wired in parallel (12v).

battery 3 and 4 could be for wheel chair lift, or any number of school bus accessories.

no deep cycle for starting batteries. 2 commercial group 31. 1 battery will be a bit over 1000 CCA.

if you had deep cycle in there, that was definitely a service battery for an accessory.

[Brewerbob]

Originally Posted by xciter101

So, now, how many CCAs do I need to turn this 8.2 over,

After sitting for 10 yrs, I would say about 1.21 Jiggawatts.

Originally Posted by EastCoastCB

I'll bet one g31 would start it just fine.
Two would surely do the job.
IDK why anyone would need 4.

What were batteries like back in 1980? My '72 Duster with a slant 6 didn't need anything special but if batteries were only 300~400CCA, I could see 4. Maybe it was a cold weather bus as well?

Originally Posted by turf

like eastcoast said, 2 group 31, wired in parallel (12v).

no deep cycle for starting batteries. 2 commercial group 31. 1 battery will be a bit over 1000 CCA.

One 8D battery is 1400 CCA. Mine has 2 with no ramps, etc.

[Jolly Roger]

Originally Posted by EastCoastCB

I'll bet one g31 would start it just fine.
Two would surely do the job.
IDK why anyone would need 4.

I have the 8.2 in a ford chassis, Thomas body.
I have two group 31 batteries wired in parallel to provide the cold cranking amps but I have started the bus on with one battery. But that was in the spring,summer in NC and after sitting for a few weeks.
I would recommend dropping and cleaning the fuel tank or just to get it started run a new fuel line from the filter suction to a fuel can sitting on the ground.
But before even attempting a new fuel filter and clean fresh fuel are a must.
I have the wiring diagrams for Thomas body that have some GM wiring on them.
I suck at posting pics on here so I can text them to you if you want them to help with the switch.
252-503-8801 let me know.

[Jolly Roger]

Admin. Might holler cause I posted a phone number so PM me and we can do it all secretly if they don't like it.

[Brewerbob]

Originally Posted by Jolly Roger

Admin. Might holler cause I posted a phone number so PM me and we can do it all secretly if they don't like it.

If an admin bitches about that, they need slapped up side the head. It's your number. As long as you don't care about some knucklehead sending it to Amway and the Christian Science folk then who else would care?

[xciter101]

Thanks, everyone. I got impatient yesterday, while I was away from the internet and put one battery @ 650 CCA in the beast.
My plan was to bump the engine over, just to see how it would fair and had my jump box at the ready.
I couldn't bump it quickly enough. I don't think it made one revolution before it was idling without even a puff of smoke to speak of.
I immediately shut it down in disbelief of what had happened. Once I came out of shock and stopped uttering slight profanities under my breath, I turned to my dad who was speechless. Did a quick walk around and then fired it back up and let it idle for 2-3 minutes. Gauges all looked good normal so we drove it a couple hundred feet. I'm still somewhat disillusioned but very happy so far.

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[Brewerbob]

Originally Posted by xciter101

Thanks, everyone. I got impatient yesterday, while I was away from the internet and put one battery @ 650 CCA in the beast.
My plan was to bump the engine over, just to see how it would fair and had my jump box at the ready.
I couldn't bump it quickly enough. I don't think it made one revolution before it was idling without even a puff of smoke to speak of.
I immediately shut it down in disbelief of what had happened. Once I came out of shock and stopped uttering slight profanities under my breath, I turned to my dad who was speechless. Did a quick walk around and then fired it back up and let it idle for 2-3 minutes. Gauges all looked good normal so we drove it a couple hundred feet. I'm still somewhat disillusioned but very happy so far.

Congrats!! I dunno if I would have done that without a complete fluids change tho. I guess diesels are forgiving but I wouldn't want funky tranny fluid or oil going thru it.

[Brad_SwiftFur]

Ah, the joys of firing off an old, all mechanical diesel engine! I fired off my 9L IH on just one group 31 battery (and the post wasn't even screwed tight, just sort of laying there). Check the oil and coolant, change both would be a good idea. Drive out the old fuel (Yeah, yeah, I know some folks are recommending draining it), but do change the fuel filters. There's probably at least 2, possibly 3. Drain the water separator if it has one (and it very well should). Check the air in the tires, they should be at least 85 PSI. How's the brakes feel? (You may have answered this, it's early for me and I'm feeling too lazy to read through.) If all is well up to this point, and you have tag/insurance, I'd ease out on the road and see how it feels.

[cadillackid]

it runs!!!!! go take a School Bus ride!! and get the biggest grin on your face you have ever had! trust me you will!!

congrats!
-Christopher

[xciter101]

Originally Posted by Brad_SwiftFur

Ah, the joys of firing off an old, all mechanical diesel engine! I fired off my 9L IH on just one group 31 battery (and the post wasn't even screwed tight, just sort of laying there). Check the oil and coolant, change both would be a good idea. Drive out the old fuel (Yeah, yeah, I know some folks are recommending draining it), but do change the fuel filters. There's probably at least 2, possibly 3. Drain the water separator if it has one (and it very well should). Check the air in the tires, they should be at least 85 PSI. How's the brakes feel? (You may have answered this, it's early for me and I'm feeling too lazy to read through.) If all is well up to this point, and you have tag/insurance, I'd ease out on the road and see how it feels.

I absolutely understand being cautious with the fluid changing but I've done old gas vehicles so many times that I couldn't wait. And typically I had a harder time than this. I'm actually going to pick up an RV today and start that battle with its 454 BB Chevy that's been sitting about 10 years also.
The brakes feel great and the tires look good too. All of them were still fully aired up. I am eager to take it around the block one time.

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