Hi everyone, you may remember the Cherokee that I installed the 4JB1TC in last year. It now has
over 30,000km on it with no problems. Increasing the intake pipe from 1.5 to 2.25 inches and crankin
the pump a quarter turn made a noticable improvment on power.
So now I'v started the next conversion and have the engine sitting in the frame on its new mounts.
Still waiting for time to get the adapter plate finnished but have been working on figuring out the wiring for both the Dakota (1999 4X4 club cab) computer and the 4HF1 computer. Looks like this was the last year before full computer control
of the 4H motor and it only controlls warm up, EGR and exaust brake. I could basically run it without the ECM but will see if I can get it to work.
The big problem so far is that the engine is 24 volt and the Dodge is 12 volt, I would like to keep my 24 volt alt since it has the vacuum pump built onto it
and like the rest of the motor only has a few thousand miles on it. Any ideas?
I had to install a three inch body lift kit in order to get starter clearance but that just gives me the excuse to put BIG tires on it.
I will try and get a web page up in the next few weeks for those that want to follow along.

BFN
Randy

Back in the early '50s, they used to use a large, step-down resistor on the output side of the generator to solve this type of problem when putting a 12V generator in a 6V-wired vehicle.

It should be easy and fairly cheap to come up with a much more elegant solution with something electronic that essentially does the same thing.

EVguy--

I think the difference between a 12v alternator and a 24v alternator is additional turns on the windings and the use of a 24v regulator instead of a 12v regulator. The extra windings will allow the alternator to produce more voltage than you will need at 12v but should not prevent it from working OK at 12v if you use a 12v regulator.

Perhaps you could scrounge up a 12v regulator and install it yourself or you could take the unit to a repair shop to see if they think this would work and if they can do it.

---Caveat: I have never tried this myself.

Or, perhaps a better idea is to look for an alternator from
an NPR (if NPR's are 12v?) or a C223 as both of these have an Isuzu type vacuum pump on them.

Paul

If it's any help, the Chev S10 diesel used a separate vacuum pump, that ran off it's own pulley. This gives you the opportunity to use whatever alternator suits you.



Finding one may be a bit tricky. It shouldn't be impossible, though.

Keep us posted.

I did look into having it converted to 12 volts which basically involved replacing all the guts with 12 volt NPR stuff.
The other problem is then the starter is still 24 volts.
We use 12 volt electric vacuum pumps on all our electric powered trucks so I can go that way and use a standard alt.
We also use DC-DC converters a lot and could run a 24 - 12 volt converter to run the 12 volt system or convert both alt and starter to 12 volt and get an ECM out of a 12 volt NPR.
So many choices, so little money.
I pulled the cab off the truck today and pressure washed it so I can give it a coat of gloss black epoxy paint.
I hope to install all the running gear into the chassis and then drop the cab back on.
I hate trying to wiggle around an engine compartment when your trying to figure stuff out. This way I can work on the engine, exaust, fuel sytem, all out in the open.
Like on the Jeep the tach sensor is going to be a problem, it had a sensor on the block that picked up gaps in the ring gear. I supose I will build a smaller version and bolt it to the front pully, I was going to try this on the Jeep but might get the Dakota running before my wife lets me "fiddle" with her Jeep.

BFN
Randy

My rover is setup with a 24v/12v split system. The batteries run in parrallel for normal running/charging but kick into series for starting (accessories remain 12v during starting).
I'd love to be able to give you the name and model of the switching block which accomplishes this, but the stick on label has long ago faded and fallen off.

As for vacuum pumps/alternators, I forked over the equivalent of $US500 about a year ago for a 70 amp alternator with a vacuum pump on the back. Given the choice again I'd be mounting an electric vacuum pump right beside the brake booster and running a normal alternator which is much much cheaper.
Chopping a 24v alternator down to 12v leaves you with the same amps but only half the power. My vehicle used to have one and on full beam with the stereo going it couldn't keep up.