L185DT alternator

Oil pan 4 · Sep 25, 2017

I'm buying my friends L185DT tractor.
The only issue with it he has ever mentioned is after the 5 or 6 years he's had it just recently developed a problem where "the starter is killing the battery". He replaced the battery, then the starter and says the new starter is now bad, because it won't start.
I'm thinking it's the alternator.
He doesn't think it's the alternator since a new one was put on just before he bought it, I think it look like the original alternator from 30+ years ago.
I have a battery and alternator 100amp resistance tester and my fluke87 series multimeter and I know how to use them. So a starter, battery or alternator problem will quickly be solved by me.

If it's the alternator which I think it is, I have a supply of SI10 and SI12 alternators from my old GM vehicles just collecting dust. They make a lot more amps than the 25 amp denso.
The reason for going to a GM alternator is its free and I have spares, I would like to run a sprayer, more lights and use a power inverter off this tractor. So more than 25 amps would be nice.
Has anyone put a GM style alt on an older tractor like this?
It looks like it will fit and I can make brackets. I can build an SI based charging system from the ground up, it's actually pretty easy.

North Idaho Wolfman · Sep 25, 2017

Put one on a B7100, so an L should be a walk in the park.

Dave_eng · Sep 26, 2017

I have made the conversion to the Delco unit many times.

There are now web sites where you can find special pulley's and mounting brackets for the Delco so it can be driven by a wide flat belt for example.

Dave M7040

Oil pan 4 · Sep 27, 2017

I think the L185 series uses a little 3/8 belt. Actually I think all kubota diesels I have worked on, 90s stuff 2 and 3 cyl, all had 3/8 belts too.
I think I have a 3/8 pulley for a GM alt in my pulley collection.

Dave_eng · Sep 27, 2017

Glad you believe you have a working belt pulley.

Another aspect which can rear its head is too low a rpm for the alternator now being installed on a diesel engine which turns at much lower rpm's than its original gas engine.

I mention this not for you but just for others who may not be as knowledgeable.

A picture when you are done would be nice to have.

Dave 7040

Oil pan 4 · Sep 27, 2017

One good thing about the old SI serries alternators is they are wye wound. They don't put out as many amps as they could for their size but they have a low cut in voltage.

Oil pan 4 · Oct 7, 2017

I found the main alt wire had rubbed through and was arcing. The alternator power just isn't getting to the batt lol.

Randyj · Oct 17, 2017

So........
Are you good with that, or do you still plan on installing a GM alternator for running the extra's you spoke of?

Oil pan 4 · Oct 19, 2017

The batt wire is burned up and I'm still planning on adding additional lights, my portable winch, using my xantrax 2000w pure sine wave power inverter, sprayer and so on, I'm pretty sure the battery is shot too. So it will also be getting a bigger battery, new starter wiring.

Yeah still planning on putting on one of my old SI12 alternators and running a much thicker wire from the alt to the batt.
This is all garage season stuff that I will start doing some time in November.

This will probably be my only garage season where the tractor will go in and not see the light of day again till spring. Next year I hope to have a loader, so garage season will last from November till it snows. I have the money set aside for a loader the problem is finding one.

Oil pan 4 · Dec 15, 2017

It got the alternator kind of in there.
Turns out its a pretty good fit.
The belt cover won't fit any more and I will need to find a shorter 3.5 inch long bolt for the lower block attachment point.
The alternator tensioner arm will need to moddified.

Edit: found a 90mm long bolt, it should work. I think 80mm would be perfect but Lowes didn't have any.

Dave_eng · Dec 15, 2017

Oil pan 4 said:
It got the alternator kind of in there.
Turns out its a pretty good fit.
The belt cover won't fit any more and I will need to find a shorter 3.5 inch long bolt for the lower block attachment point.
The alternator tensioner arm will need to moddified.

Edit: found a 90mm long bolt, it should work. I think 80mm would be perfect but Lowes didn't have any.

When faced with the too long bolt situation, I make my own from the too long bolt.
I cut off the excess, and then mig weld a nut to the bolt shank.

Select a nut just larger than the shank to make the welding easier.

Alternatively, the tap and die sets which go on sale very cheap periodically, usually have a metric tap and die to fit most smaller bolts. Extend the threads up the bolt shank and then cut off excess.

Don't make the mistake of running a too long bolt into a blind hole (one with a bottom) as you will tear a piece off of the block when the bolt hits the bottom of the hole.
Dave

Oil pan 4 · Dec 15, 2017

I thought about doing that but I really don't want the bolt to break.
It's an 8x1.25 thread I didn't think it would be difficult to find.

billrigsby · Dec 16, 2017

Oil pan 4 said:
One good thing about the old SI serries alternators is they are wye wound. They don't put out as many amps as they could for their size but they have a low cut in voltage.

Oil pan 4 said:
It got the alternator kind of in there.
Turns out its a pretty good fit.
The belt cover won't fit any more and I will need to find a shorter 3.5 inch long bolt for the lower block attachment point.
The alternator tensioner arm will need to moddified.

Can we see some photos and maybe how you did the wiring to get rid on the external regulator?

Oil pan 4 · Dec 16, 2017

It has an external regulator?
Where at?
I thought I had the wiring figured out, hadn't started working on it yet. I assumed it was a denso 4 wire, internal regulated.
I hadn't taken my multi meter to the small wires to get an idea as to their function.

billrigsby · Dec 16, 2017

Oil pan 4 said:
It has an external regulator?
Where at?
I thought I had the wiring figured out, hadn't started working on it yet. I assumed it was a denso 4 wire, internal regulated.

I'm guessing on the 185 it's in the same place as it is on the 175 and the 1500, up inside the instrument panel.

Oil pan 4 · Dec 18, 2017

I looked for it and found it.
Should be pretty easy to do away with.
I was just going to take the IGN and lamp wires that plug into the regulator and extend them to the IGN and lamp ports on the 12si.

Oil pan 4 · May 9, 2018

I have been using my riding mower and not messing with the tractor. I did get my PTO brush shredder fixed and bought 3 new tires and 4 tubes for the kubota.
Now the mower is broke, the carb dumping gasoline into the V-twin engine.
So back to working on the tractor.
I got the alternator on. I installed it pretty much up side down. The adjust bolt mounts on the block and there block attaching point connects to the tension holder.
The old alternator bracket just needed to be put in a vice and abused with a hammer.
The alternator needs to be clocked so the battery charge wire is pointing down, that way it's closest to where it needs to be and the wire is kept away from the block and exhaust system.
The charge wire needs to at least be 10 gauge, I went with 8 gauge.
I removed the external regulator, I'm going to jumper the ignition power wire to the existing alternator wire, then hook up the voltage sense wire straight to the battery.
Hell the original alternator belt fit, it was kind of streached out, expect finding the right belt to be a chore if it doesn't fit, unless you further modify the alternator tension bar and make it a bit longer.

I'm just going to figure out the wire functions with my multi meter. Trying to look them up takes too long.

Oil pan 4 · May 14, 2018

Looks like 1970s kubota and 1960s GM have 2 different schools of thought as to how the alt ID10T circuit should function.

I figured out how to make the alt light come on, but the alt never builds up volts. But if I put 12v on the #1 terminal of the alternator it builds up volts then reconnect #1 to the light circuit on the tractor the light stays off and the battery charges.
What I will probably do is wire in a momentary "alt reset" switch to hit the #1 wire with 12v after every start.
A momentary switch is the kind that turns on only as long as you hold it, when you let go it returns to the off position.

Dave_eng · May 14, 2018

Oil pan 4 said:
Looks like 1970s kubota and 1960s GM have 2 different schools of thought as to how the alt ID10T circuit should function.

I figured out how to make the alt light come on, but the alt never builds up volts. But if I put 12v on the #1 terminal of the alternator it builds up volts then reconnect #1 to the light circuit on the tractor the light stays off and the battery charges.
What I will probably do is wire in a momentary "alt reset" switch to hit the #1 wire with 12v after every start.
A momentary switch is the kind that turns on only as long as you hold it, when you let go it returns to the off position.

Much simpler to install a voltage display that works completely independent of the alternator and cost less than $10.

Many different styles on Ebay.com

I suggest this one because it is already in the USA and arrives quickly

https://www.ebay.com/itm/Digital-Vo...ZMX8iNG_0ST_SvQ:sc:USPSFirstClass!01370!US!-1

Convert your Delco alternator to a one wire installation by leaving the jumper permanently in place.

The smaller forum Denso alternator is proving popular because it is much smaller than the Delco, GM is now using them on their new cars.

For the display, one terminal to ground and the other to a + terminal on the key switch. Now you will even see battery voltage while cranking and be better able to determine when the battery is near the end of its life. Many colors available.

I put them on my ATV, Suzuki GS100 and various garden tractor none of which provided any info on charging status

Dave

Oil pan 4 · May 15, 2018

Dave_eng said:
Much simpler to install a voltage display that works completely independent of the alternator and cost less than $10.

Many different styles on Ebay.com

I suggest this one because it is already in the USA and arrives quickly

https://www.ebay.com/itm/Digital-Vo...ZMX8iNG_0ST_SvQ:sc:USPSFirstClass!01370!US!-1

Convert your Delco alternator to a one wire installation by leaving the jumper permanently in place.

The smaller forum Denso alternator is proving popular because it is much smaller than the Delco, GM is now using them on their new cars.

For the display, one terminal to ground and the other to a + terminal on the key switch. Now you will even see battery voltage while cranking and be better able to determine when the battery is near the end of its life. Many colors available.

I put them on my ATV, Suzuki GS100 and various garden tractor none of which provided any info on charging status

Dave

I am well aware of the 1 wire conversation. I also know why it sucks. When you go to 1 wire you lose remote voltage sensing. As the alternator puts out more amps the voltage at the battery drops.
The one wire conversation is mainly for people who don't understand charging systems, can't read a schematic or don't know how to use a multi meter.
With 3 wire operation I get a steady 14.4v at the battery until the alternator output is exceeded.
I do need to install a voltage meter so I don't drain the battery with lights and stuff.

L185DT alternator

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