I’m not as observant as CTSnowfighter; he mentioned the serial on my latest D2;
D24U1275 SPG??? I’ve never seen a Cat with the G; I know what SP is regarding special part(s)
I also noticed the tractor was POSITIVE ground...wth??? Scary part is the rear worklight came on and the generator is working... I don’t even know how old the Exide brand battery is, I added water to it and it actually holds 6 volts still!
Any help on this one would be appreciated.
Thanks in advance, JM

I have 4U 1098SPG, it had a generator and electric pony starter, think it had a rear hydraulic pump, from the Modesto area.

Nearly all automotive equipment was positive ground 'back in the day' negative ground arrived with the alternator, now everything is that way.

Maybe in England's automotive world?
I maybe mistaken but I seem to remember a lot of the 1950's and 60's 12 volt Delco generator systems being negative ground.

Hi, Catsilver.
I'm with Drujinin on this one. I can remember seeing British-built vehicles from way back when with a positive ground but not any American-built vehicles.

Just my 0.02.

I can’t speak to the automotive side,
but I know John Deere used positive ground for a long time. All the 40’s 420’s 430’s and a 70 Diesel I’ve been around were positive ground. We had two ‘69, 95H combines, they had warning stickers to inform folks that they had switched to negative ground.

Can’t help on the SPG, though.

BP.

Positive earth was standard practice on UK built equipment, it was around the early sixties that everything started to change. Very confusing when you are fixing up your Dad's old car over the weekend, and the old motorbike to get back to work on Monday, then the first job is to jump start a 955H!

"josh" wrote:

I have 4U 1098SPG, it had a generator and electric pony starter, think it had a rear hydraulic pump, from the Modesto area.

Josh: This one originally came from the Central Valley, possibly from Fresno area? Along with the “odd” suffix letter G, it has a generator, worklight and a BeGe pump on the back. Maybe some one can tell me if it really came from Peltzer’s sale or somewhere close by? Seller said he bought at auction a couple years ago.
I’m wondering if some goober just installed the battery backwards; my new Snap On test light which reads voltages will show “green” 7.9 volts at the generator vs. 6 “red” at battery??? No, I didn’t read the instructions on how to use my tool...
The battery box is in perfect shape; ammeter still works and it has a set of triple toggle switches which look factory as well. All in all, I’m really happy with this tractor.
Unstuck the rack and the plungers, cleaned out the fuel system on the pony/flushed tower/lines/new socks for the main: fired up easily. Steering/main clutch/brakes all still in perfect adjustment. Drove her around until I noticed the Sylphon fuel pressure gauge quit working. Oh, maybe it was because I ran it out of fuel?
Maybe that’s why it shut it self off. LOL. Never did that before!!!
***on another note, I am planning on purchasing a handheld tachometer to test the RPMs: seems this one has WAY more power than my 5U1600; wondering if someone reset the governor!!!

JM - How could you run out of fuel?
Do I remember right - you unscrew the cap and there is a screen, alongside the screen there is a dipstick?

Happy to hear you have it running!

Positive ground - Ford Tractor was positive ground too, been a long time but I think many other industrial applications also positive ground.

The "G" on serial number -- I did not look close enough, is the generator gear driven from the cam/crank etc.? There might be a different front Timing Case Cover to accommodate the gear driven accessory?

My bet, Old Magnet will enlighten us soon.

cts

As far as I know all the early US Cat stuff was negative ground, both Delco-Remy and American Bosch 6V, 12v and 24V.
Delco-Remy did produce positive ground generators so could be an interchange.

The "G" designation is a new one on me too. Might just be for the Generator application.

All the 4U/5U D2's would have provision for SAE mounting flange for generator if they had the adapter housing and the adapter could be mounted to all "U" model D2's.