Converting 6 volt to 12 volt on Cletrac HG Or Oc3

jr/w.pa

New User
I have 3 Cletrac Hg"s And Oc3"s that I am thinking of changing from 6 volt to 12 volt. Would like some advice on what I would need to do this. ie any particular brand or type of alternator and what size or gauge wire to re wire( Wiring is old and should be replaced)Any helpful suggestions would be greatly appreciated
 
Most old tractors were positive ground,when an alternator is fitted the polarity has to be changed to negative ground,most people use the six volt starter and finds that it lasts a long time,if it does fail a twelve volt can be fitted in it's place,have a look at the sketch below to give yourself an idea how it goes,I wind to disregard the old generator charging circuit is best as to keep wiring to a minimum.
AJ
36132.jpg
 
We did this with a 1954 flathead Ford (1954 was the last year in OZ) and they came with Lucas electrics.

Our autolec recommended putting 12 volt fields in the starter. Might be worth a thought.

Somewhat perifferal but from same autolec

The Oz successor to what you had as a 250 cid Ford Falcon 6 here used a 6 volt armature in a 12 volt starter to get enough oomph. Now replaced by Bosch planeterys.

And I've been dealing with that autolec for 50 years and he's usually got the answer or he'll find it.
 
It can be converted for around 60 bucks. Get u a Delco alternator. some buy a one wire and some buy a three wire. Any auto parts store will have them. Around 50-60 dollars. Multi-wire will need a diode to prevent feed back from the battery. One wire doesn't but parts for a one wire are higher. Check your wiring. probably don't need to replace all of it. Just the bad wires. Your starter will work fine but remember to use the 5-10 second rule when trying to start. once you do this you will be happy you did. With the price of batterys now it pays to do this. I have done this on 3 tractors with great results.
 
The big Delco 10SIs and 12SIs often sold for farm tractors are not a great fit. A mini-alternator made for forklifts is perfect. Nothing needs to be done to the starter motor but keep this in mind. 12 volts makes that starter engage and crank much faster and it is a VERY expensive starter to replace. I have several HGs and have been looking for a spare in case I need one later. Prices are crazy high. And new? Delcos are near impossible to find. New Autolites are over $300.

Does your crawler have an aux. trans? Awful fast in the lowest gear without.
 

I did a conversion on my OC46 using the thread on the Cletrac forum referenced by JDEM.
http://cletrac.org/forum2010/index.php?topic=2227.0

I purchased my alternator from RareElectrical, best price and great service. I have used them a few times. I didn't use the exact alt that was used in the conversion thread but one from the same series.
http://www.rareelectrical.com/

I plan on using the same parts to convert my OC3 as well.
 
I have 3 questions
1.did you have to modify a bolt( like the one on HG/ OC3
Cletrac discussion page) to mount the pulley.
2 Could you list the name and model number of the alternator you
used from rare electrical..
3. How difficult is it to wire.
 
(quoted from post at 17:59:43 05/24/16) I have 3 questions
1.did you have to modify a bolt( like the one on HG/ OC3
Cletrac discussion page) to mount the pulley.
2 Could you list the name and model number of the alternator you
used from rare electrical..
3. How difficult is it to wire.

I did the conversion about 5 years ago so I am going by a fast fading senior memory.

1. Yes, you need to adapt the original pulley to the metric size of the alternator. It is pretty easy to do on even a small hobby level lathe.

2. I looked at my alt. today but the foil tag is gone. At one time when replacing the battery I mistakenly hooked it up backwards (pos grd instead of neg grd like the alt needs) and fried the built in regulator. I found the receipt for a replacement and it shows 4 alternator #'s that it fits. One of those is Denso 101211-1170 which Hotratz used in his conversion so I feel confident that I used it as well.

http://rareelectrical.ecomm-search.com/search?SearchTerm=101211-1170

This page shows many JD tractors that use it, stop by a dealer and find one of the tractors and take a look. They are tiny units which is what you need to fit in the OC3 engine bay.

3. It is not hard to wire up. You need to switch on/off the field excitation circuit. Hotratz used a key switch, I used a oil pressure switch that closes the circuit when pressure reaches 7psi or so. These engines only make 15-20 psi so not any switch will do. I found a receipt for NAPA Part # ECH OP6894 which is probably what I used. IIRC it was for a early 1990's Jeep with a 4 cyl. I put in a "T" where the oil pressure gauge line goes into the engine and put the switch there. I wired it like Hotratz shows for "switched field excitation". I didn't use a warning light.
You need to get a plug/pigtail to fit the alternator. My son who works on Hondas happen to have one as some small Civics and Corollas use the same plug. Rare Electric would most likely have them.

You will be converting to neg ground, the starter won't know the difference although if you have an ampmeter you will have to swap the wires so that it moves in the right direction. If you have lights you probably will have to change to 12V bulbs.

The conversion is well worth the effort. Your engine will spin over much quicker. Hotratz has a video on YouTube that shows his conversion running, just search there for his name.
 

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