3020 LP ignition

I have a question on my 64 model 3020lp. I would like to install a pertronic module. What coil should I use with it and should I install a resistor before the coil. When I measure voltage to the + side of the coil I get about 10.5 volts and the ohm reading across the primary windings + to - is 6 ohms. Thanks
 
I put a P on my 70 and got the coil they sell to match it. I forget the cost of the coil, but I figured it was cheap insurance. Since it was matched, no resister or other gizmo's were required. It's run
well with it since then, which has been years enough ago to forget the price. Course I'm at the stage of life I can't remember what I had for breakfast, or whether I even had breakfast.
 
Steve, excellent question, let an engineer provide you with assistance.


1) First of all the decision to upgrade to an electronic ignition is YOURS ALONE, none of ours, so I will dispense with a discussion of the advantages or disadvantages.


2) REGARDLESS how your tractor was original, as a past tractor dealer I saw literally hundreds that were modified over the years ESPECIALLY regarding original POSITIVE Ground or NEGATIVE GROUND plus the use of external ignition ballast resistance devices when a 6 volt coil was used on a 12 volt tractor, many of which went bad and were removed or replaced or by pass jumped around and perhaps a substitute 12 volt coil was used. I CAN NOT KNOW WHAT YOU NOW HAVE?


THEREFORE IT IS IMPERATIVE FOR YOU TO DETERMINE IF:


A) YOUR TRACTOR IS NOW POS OR NEG GROUND ?????????????

B) WHETHER OR NOT THERES A BALLAST RESISTANCE DEVICE BETWEEN THE IGNITION SWITCHES IGN OUTPUT AND YOUR COIL INPUT ??????????????????

C) WHETHER OR NOT YOU HAVE AN OPERABLE BALLAST BY PASS SYSTEM


I JUST SAW SOOOOOOOOOOOOOOO MANY TRACTROS MODIFIED OVER THE YEARS

Based on your post, there?s a chance you still have a ballast (since you read 10.5 volts instead of 12 if all was well and points were closed, UNLESS YOUR BATERY IS LOW OR YOUR METER INACCURATE) but that 6 Ohms across the coil seems inconsistent with what I would expect ??????????????

!!!! YOU MUST ORDER THE PERTRONIX TO MATCH YOUR GROUND OR YOU CAN FRY IT !!!!

NOW FOR MY ADVICE

The above being said, and to get the most bang for the buck and reap the benefits which an elec switch has to offer, I WOULD CHOOSE THE AFTER MARKET HIGH ENERGY COIL PERTRONIX RECOMMENDS (such as their Flame Thrower) THAT?S SUITED FOR AND IS COMPATIBLE WITH THE SWITCH YOU USE !!!!!! The thing is even with an old stock coil of the correct voltage and resistance, sure you still get a spark and reap the advantage of rapid positive switching versus ringing bouncing burning mechanical points, HOWEVER if you upgrade to their switch and a properly matched (Voltage and resistance) high energy coil, you can end up with more spark gap energy !!!!!!!!!!!!!!!

While you can still use an existing ballast if you still have one but that would determine what coil you use I WOULD REMOVE ANY OLD BALLAST (if it still has one) and you can get by without the use of any ballast by pass such as when they used 6 volt coils on 12 volt tractors,,,,,,,,,,,,,,I would order a Pertronix elec switch such as their Ignitor that matches your ground,,,,,,,,,,,,,,,,,,,,I would talk to Pertronix and buy a new High Energy Coil such as their Flame Thrower (THEY recommend NOT any of us here) that?s suitable for and compatible with the switch you so choose,,,,,,,,,,,,,,,,,,,I would likewise talk to Pertronix regarding the choice of plug wires as for many units they do NOT recommend wire core plug wires.


SURE you could use any existing ballast resistor and SURE you could use an existing coil of the correct voltage and resistance and SURE you could still use a 6 volt coil and a start by pass system BUT IF YOURE UPGRADING TO AN ELEC SWITCH WHY NOT USE THEIR RECOMMENDED HIGH ENERGY COIL AND DO AWAY WITH ANY POSSIBLE OLD BALLAST PROBLEMS (Including any start by pass system) ????? START ALL NEW


BOTTOM LINE, Use the coil Pertronix suggests that matches your switch (THEY will recommend the correct voltage and resistance of the coil) and ask them about the best plug wires that suit your coil and switch???..

Hope this helps: Determine your Ground,,,,,,,,,,,,,,,,,,,,,Determine if you still have any ballast device,,,,,,,,,,,,,,,Talk to Pertronix to choose your switch and coil and decide whether or not to still use your ballast if it has one (but that affects the voltage of your coil remember, I would toss it and use a full 12 volt rated Flame Thrower coil instead).


Best wishes, post back any questions (better yet ask Pertronix) God Bless and Happy Veterans Day


John T BSEE, JD Retired Electrical Engineer
 
Susan you your statement

"I forget the cost of the coil, but I figured it was cheap insurance. Since it was matched, no resister or other gizmo's were required"

I say WISE CHOICE

John T
 
Readings are not right so either you did it wrong or there are issues with current setup. Coils typically come in 1.5 or 3 ohm flavor only and this single anomaly might skew your results where they are depending on whether the points were open or closed when you measured 10.5 volts.

<a href="http://www.yesterdaystractors.com/40511_Coil-High-Performance-Black-12-Volt-Oil-Filled_1502.htm" target="_blank">Coil, High Performance (Black), 12 Volt, Oil Filled</a>

This coil would work fine, and comes from this very site. I highly recommend this coil and have several myself including unused spares for retrofit any time I want to do that. You can buy cheaper, but never a cheaper higher performance coil.

Resistor would not be needed or even desired. Only caution I can think of is to do some thinking on which 12 volt ground system you want to invest in because once you buy the pertronix you are kinda stuck with positive ground (if that was your choice with this decision) unless you don't mind buying two pertronix units and only using one of them. Issues for consideration would be replacement generator VS cheaper negative ground alternator. Jumping of the tractor done by idiots in my unforeseen absence would worry me for example.

The negative ground version is almost 10 dollars cheaper and also from this site.
<a href="http://www.yesterdaystractors.com/cgi-bin/store/model_parts.cgi?SearchArea=John-Deere&&md=3020&cat=Electrical%20System&r=mcats" target="_blank">Electrical System John Deere 3020 Parts</a>
 
I agree, his reported 6 ohms for a coil seemed strange as well as that 10 volts????????, NEITHER was what Id expect. That "Flame Thrower" coil (provided it suits the switch he chooses) should do fine for him with any external ballast removed.

Nice chattin with you

John T
 
Just an FYI, I see talk about a ballast resistor, but no talk about the spark ignition 3020’s having a resistance wire going to the coil, I learned that when I converted the gas one to the 239.
 
Indeed Mike, some tractors (that used a 6 volt coil on a 12 volt tractor) used a stand alone bathtub style "ballast resistor",,,,,,,,,,,,, others a piece of whats like a resistive wire link,,,,,,,,,,,,,,,,others a resistor wire located on or near the ignition switch, all of which to speak of in general terms I refer to as a "ballast device". REGARDLESS which he has or what it may or not have been replaced with over the years I think Id use a full true 12 volt rated coil (like Pertronix Flame Thrower) matched with his elec switch AND NOT USE ANY BALLAST DEVICE, but its his choice fer sure.

Nice chatting with you, Happy Veterans Day

John T
 

Any old Napa coil will do . Depends if you want bypass starting with a resistor and a 1.5ohm 6V coil. Or a 12V coil with 3.0ohms and no ballast resistor .
 
When I install the pertronix units, I use their flamethrower coils and resistor plug wires. Bypass the resistor wire from the switch and wire according to the instructions. I also only use negative ground units and switch battery polarity if needed. That said, the instructions will show wiring for several scenarios including with or without resistor and pos. or neg. ground. By converting to neg ground, it prevents problems if someone should install an alternator in the future to replace a generator that was pos. ground
 
Thanks for the replies, I also thought the ohms reading was strange. I will contact pertronics and go with what they recommend. I like John T's idea of going all new as I do not know all the mods that may have been done over the years. It is a neg ground system. Thanks again, The knowledge available here is fanatastic.
 
gap should be 40thou . Wires should be spiral wound suppression , solid core will burnout the pertronix unit. Non resistance plugs recommended .
 

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