4020 24 volt to 12 volt

Hayfarmer Frank · Feb 21, 2012

I"ve had it with my 4020 24 volt positive ground system. I went out and purchased a 12 volt starter, alternator, and selinoid. Does anyone have wiring diagrams for this conversion? I dont know what to do with the wires from the voltage regulator.I want to rewire the entire system, but I need to rewire the basics now to get the tractor up and running.

Thanks in advance.

David G · Feb 21, 2012

It would have been prudent to talk with folks here before you bought the parts. I would not install a delco starter, the denso spins much faster. Most of the kits contain the slower delco.

This may be a point of contention, but I would put a 12/24 series parallel switch on and keep the 24V starter. It spins over nice and needs smaller cables.

gregger · Feb 21, 2012

google it , lots n lots of notes on it

tim s · Feb 22, 2012

I have been getting a new Iskra starter from my starter shop for about $350,a self exciting Delco 10si alternator for about $90, a couple 18" ground cables and a solenoid to make the switch,My starter guy will ship to you,a couple a wiring changes and it will all work out sweet and easy, you will be glad you did it...

Tx Jim · Feb 22, 2012

Route both positive battery cables to large top post on 12 Volt solenoid along with the blue & brown supply wires in original wiring harness. Attach original yellow wire that was on 24V solenoid to axillary(extra) solenoid "S" terminal. Route both ground cables to frame or better yet a starter mounting bolt. I know Tim states to tie one generator wire(brown I think) to alternator and tape up the rest of the wires so they don't touch each other.

Hayfarmer Frank · Feb 22, 2012

Thanks for all replies.

TX that sounds easy, and very understandable.

Jim I will give you a call thanks for the email.

I purchased a gear driven starter (direct drive) and a 72 amp alternator. I thought this was good, but maybe not.

Tx Jim · Feb 22, 2012

It is really not hard even with all the bad 24V bad reputation. Maybe Tim or someone else will clarify the generator to alternator wiring conversion.

55 50 Ron · Feb 22, 2012

please note, he didn't say what brand of starter he purchased.

Tx Jim · Feb 22, 2012

(quoted from post at 11:38:56 02/22/12) please note, he didn't say what brand of starter he purchased.

Ok curiosity killed the cat :roll: What does starter brand matter as long as it's built for a 12 V 4020 diesel?

Mike M · Feb 22, 2012

Is that Iskra starter a gear reduction type ? I put a late 4020 12volt starter on a JD500 ind. (3020) once and it didn't spin very fast and would not start good when cold out.
Does that one spin them fast ?

tim s · Feb 22, 2012

It matters a lot...Nipendenso #1 choice, Iskra #2, Delco last resort..My choices...

tim s · Feb 22, 2012

No they are direct drive but they work well, I use them a lot on conversions.

Mike M · Feb 22, 2012

Ok if the nipendenso is # 1 they why use # 2 choice ? is it alot more money ? and then why is it # 1 does it turn over better or just last longer over the years ? Just trying to learn here because if I try another one I want better results then I got with the Delco from a late 4020.

Tx Jim · Feb 22, 2012

Iskra will be quite a bit cheaper than a Nippodenso.

tim s · Feb 22, 2012

The Nipendenso will out last 3 Delcos, they are good but pricey about $475,,the Iskras are good, nice speed and they cost about $350,,the Delco's (even though I'm for made in USA stuff) are not so good and are a bit slower, it seems that the frames being bolted on each end seem to flex a bit and cause them to drag and fail..I have been using Iskra's for about 6 years and haven't had one fail,,yet...This has been my experience..

Tx Jim · Feb 22, 2012

(quoted from post at 16:30:31 02/22/12) It matters a lot...Nipendenso #1 choice, Iskra #2, Delco last resort..My choices...

Tim
When I responded with "what does it matter?) I was thinking about there wouldn't be more difficulty in attaching the wires for conversion from 24 V to 12 V because of brand variation of starter.

Hayfarmer Frank · Feb 22, 2012

It is a gear reduction starter. I'm not sure of the brand since it is still in the box. I will check it out and let you know. Right now I'm putting brakes in a 4440, and replacing a radiator and several hydraulic lines in an excavator. Tim I will give you a shout as soon as I finish these jobs the 4020 is next in line.

Can you please explain the wiring harness your buddy can make?

David G · Feb 22, 2012

I had the Delco, had to replace it because the tractor
cranked too slow to start when cold.

I would still like to try a 12/24 switch. My dad and I converted a WW2 duece and a half from 24V to 12V. We put the switch on and it worked great. I have seen them advertised for about $125. The stock 24V starter could then be used.

tim s · Feb 22, 2012

That may work but still won't solve the 24 volt head aches,,switching to 12 is the way to go,they will match up with the modern world.

David G · Feb 22, 2012

Tim, it does, the batteries are in parallel for normal operation, then series for starting.

David G · Feb 22, 2012

Check this out
Untitled URL Link

4020_1966 · Feb 22, 2012

Email me at [email protected] and I can send you a pdf with the original 24v diagram and the 15 page instructions to convert it to 12v. i have sent them out to several people on the board before.

Tx Jim · Feb 23, 2012

(quoted from post at 00:04:32 02/23/12) Email me at [email protected] and I can send you a pdf with the original 24v diagram and the 15 page instructions to convert it to 12v. i have sent them out to several people on the board before.

Charles
I'm not trying to start a WAR but I can't believe it requires "15 pages" to describe how to change a tractor from 24V to 12V. But I've never read the 15 page document you're referring to.

tim s · Feb 23, 2012

That's nothing there is a "20" page instruction to instal the RE 38390 4020 safety switch ( I just counted them)

Hayfarmer Frank · Feb 23, 2012

(quoted from post at 06:04:32 02/23/12) Email me at [email protected] and I can send you a pdf with the original 24v diagram and the 15 page instructions to convert it to 12v. i have sent them out to several people on the board before.

Thank you. I just sent an email.

4020_1966 · Feb 29, 2012

Tx Jim

The directions are 15 pages from Deere. They are very thorough with diagrams and trouble shooting sections. I can send it to you if you want to see them. Of course it can be summarized down for anyone who has decent knowledge of automotive wiring and their 4020. For anyone else step by step detailed instructions are good.

Tx Jim · Feb 29, 2012

4020_1966
No need to do that. My reply is some good trees were wasted from JD engineers ignorance & making work for the author of the JD bulletin. Tim S posted on this forum in the past about a JD bulletin on R&R of neutral start switch that consisted of 20 pages & I'll quote Tim[/quote] IMHO R&R of neutral start requires ONE SENTENCE.Thank you,Jim

buickanddeere · Feb 29, 2012

The 12/24 relay should isolate the 24v starter leakage .

buickanddeere · Feb 29, 2012

The 4KW or 5 KW Denso 12V starter ?

4020 24 volt to 12 volt

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