I had an opportunity to help out a friend with his Very Early CJ-2A. To those who are not familiar with the VECJ-2A’s, among other things they had a three speed transmission with the shift lever on the steering column. It is a bit of a mix-master build with a new tub and various and sundry pieces and parts and is intended to be used by the grand-kids and family just to have fun.
He needed help with installing the KWAS 12 volt alternator conversion in the original 6 volt vehicle. The installation instructions with the KWAS conversion kit are, at the most generous, unclear and misleading. If followed as written, the vehicle ammeter would never show the amount of charge the alternator was delivering to the battery.
As we worked with various wires, we also found errors with the wire color codes in the harness instructions for the wiring harness he had installed. But - we seem to have gotten things straightened out and when we quit; nothing smoked, everything that had been hooked up seemed to work, the ammeter showed a good charge with the engine running and a modest discharge with the engine off and the headlights on. I'll call that success!
Awsome Larry! Good thing you were looking at that install instruction with an electronics eye! It gets difficult when the instructions have errors. Nice old CJ there.
I can feel an in depth synopsis coming to the technical folder with the whys and hows all drawn out. If anything Senior Chief just needs to rewrite the instructions and send them to Mike to put with any kits that are sold.
This was my first hands-on experience with a 12-volt conversion and I noticed two interesting things.
1. These is a misunderstanding among folks who do a 12-volt conversion that the “90-amp alternator will burn up the original ammeter”. I had explained that the alternator will only provide the current that the battery and electrical system need - it won’t force 90-amps into the system.
But, I think the gentleman was a bit skeptical about my explanation. The VE CJ had been sitting in an unheated barn for several months and it was only about 38-degrees yesterday; the engine was cold and the oil had to be stiff. He had retained the original 6-volt starter and with the 12-volt battery, it spun the L-134 pretty fast - but it took several tries to get it started. When the alternator kicked in, the ammeter only showed about a 30-amp or 40-amp charge. The 90-amp alternator wasn’t burning up anything even after an extended cranking period.
2. With the 12-volt battery, the 6-volt starter spun the engine so fast that if the engine even spluttered a bit before it actually started, the Bendix would kick out and disengage making you have to quit cranking and start over.
The starter will handle the 12 volts pretty well for a long time, but your assumption about the engine turning over too fast is warranted. When the Heep was not run regularly the cheapo good for a year battery would go dead. I'd throw the booster pack on to get her fired up until I could put the battery charger on it for a while. The engine would spin over fast, but it always seemed that it was too fast. It would not start as well with the engine turning fast in my theory that the points were snapping too quick. With a fully charged 6 volt battery, the Heep pops off pretty quick, (within 6 revolutions when cold, and not been run in a while). Most folks who convert to the alternator and 12 volts, also do the Petronix conversion, so do not end up seeing this anomaly.
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