Installing a Delco Alternator In An 'Early' Land Rover Series IIA

The author holding the freshly-removed generator

Materials

AC Delco Alternator Model SI-10. This is Delco part number 321-43, GM part number 1979867. It's a 43-Amp alternator. I don't know the numbers for bigger ones. I certainly don't recommend any bigger without replacing the wiring harness. The alternator is available at most auto parts stores. You may have to order it ahead of time, though. I bought mine through my mechanic, who gave me the wholesale price and got it from his supplier in about five minutes. However, I'm pretty sure he did this because my Rover had sat on his lot for three weeks waiting for a wiring harness to be installed (which I later did myself). I've written a document about that, too.
Alternator Bracket. I got mine from British Pacific. Guess what? They had those fabricated years ago, and have now run out of stock. So, here are some instructions (provided by John Ousterhout):

"Some modification of the stock mount is necessary to fit the Delco unit, but most folks are able to make it work by stacking washers as spacers and using a v-belt of just the right size. (Rover used two different mounting systems, one is easier to modify) I finally remounted mine on a home-made mount, but only after driving it for over 100,000 miles with a stack of washers. I needed the room for my hydraulic winch pump."

8 feet of wire in 3 types:

red 10-gauge for the alternator output
red 16-gauge for the sense wire
white 16-gauge for the alternator warning light

Bullet and spade connectors for above

Tools

You will need the following tools:

Combination Wrenches and Ratchets in the following sizes (the usual suspects):

7/16"
1/2"
9/16"

Wire shaver/cuter
Test Lamp
Volt meter or DMM
Pliers for crimping bullet and spade connectors
Soldering iron (if you choose to solder the connections)

Getting Started

First, you will need to convert your Rover from positive to negative ground, then DISCONNECT THE BATTERY. Then, remove the generator and top mount.. The whole mount can be removed with much effort. Nick Baggerly took 14 hours to do this, and I'm sure it would have taken me even longer. I left the original bottom mount on and used the top mount from the British Pacific part.

Making And Installing A Harness For the Alternator

You will need to make a harness out of the wires specified above for the the alternator. I put the spade connectors directly onto the spades on the alternator, but Alan Richer decided to solder his wires onto the plug that is sold for connection to the spades. Your choice. I then fitted a lug connector (round, washer-looking thing w/ a place to connect a wire) to the 10 gauge wire. The three wires were then wrapped in PVC electrical tape and placed in a plastic tube designed for such applications. The wires and tubing were purchased at Kragen auto in Mountain View, and are available at auto parts stores everywhere. I ran the tubing between the water pump and the block across the front of the engine to the battery, where I connected the 16-guage red wire and the 10-gauge red wire (one on each nut that tightens the battery cable to the stud connector). . I then ran the white wire inside some more of the aforementioned plastic tubing to the grommet in the fire wall through which the main wiring harness goes. The white wire is then connected to the charge warning idiot light on the dash board instrument panel.

Removing the Generator

This is not that simple (at least it wasn't for me). There are two bolts at the pulley end of the generator which have to be undone. The bottom one was a cast iron bitch to get out, and I eventually broke it by pulling the generator up. A more elegant solution is to remove the pulley from the crank, and then undo the bolt on the mount. Another solution is to loosen the existing bolt, and cut a notch in the lower hole of the BP mount and slide it over tightening the bolt afterwards.

Mounting the Alternator

Wiring

On thing that wasn't clear to me before I attempted this was that the harness should be attached to the alternator before it is installed onto the bracket. The 10-gauge red wire is connected to the lug on the alternator. The 16-guage red wire is connected to spade #1 (it's marked as such) on the alternator, and the 16-guage white wire is connected to spade #2 on the alternator.

Be sure to keep the alternator wiring harness away from the exhaust manifold. I lost the first one I made to melting caused by that. You can use tie wraps to attach the harness to the engine mount below the alternator and there is a loop by the top of the water pump that can also be used to further pull the harness away from the engine at the top.

I then took the wires that had gone to the generator and put them in the tubing for the alternator harness. That way if some future owner wants a 'correct' Land Rover, he/she can install a generator and the original wires will still be there.

Physical Mounting: First Time

Diagram I gave the machinist for the 'adapter"

How alternator is mounted to 'adapter'

I used the top mount from the British Pacific alternator bracket, but left the bottom generator mount on the engine. I used the design pictured to make this work. I put a stack of washers between the back of the generator mounts (front and back) and the "adapters". I then mounted the alternator in between the two "adapters". As a result of this hack, I needed a slightly larger fan belt (from NAPA).

Physical Mounting: Second Time

For various reasons, felt that the first method of mounting the alternator was not quite what I wanted--although it worked in several trips off-road, and never failed. I just wanted something that seemed really solid. So, when I had some time and the first alternator was acting up a bit, I went to the machine shop I use, and talked to them about it.

We ended up getting a new 60 Amp alternator (Delco part # 241-60--stock on a '72 Cadillac El Dorado), and milling 9/16" from the front part of the alternator mount point that attaches on the block. A serious spacer was also made. That left one problem: The hole in the alternator was 3/8" while the hole in the block was 5/16". So, the machinist pressed a valve guide into the hole in the alternator, and voila! The thing mounts to the engine like it was stock. That left one problem. The method I used the first time had the advantage of leaving a lot of room for adjusting the alternator, while the new method left almost none. At the suggestion of Bob Bernard, I ground off part of the engine mount directly behind the alternator. This gave me another 1 1/2" of room for alternator adjustment. The engine mount in question has two pieces of metal that stick up from the flat part that slopes down to the engine. I just ground off the front part that stuck up. Since Bob did this years ago, and frequently takes his Rovers off road, I feel pretty comfortable that this will not compromise the structural integrity of the engine mount.

Shorting the old Voltage Regulator connections

Take the wires that are attached to spade A1 on the VR, and short them together if they aren't already. Do the same for the wires on spade A. Then take all these and short them together. This gets electricity through from the ignition system to the rest of the car. The other wires connected to the VR should be insulated and tied off so they are out of the way.

Does It Work?

If you switch on the ignition and the red light comes on, then you're part of the way there. Now you just need to start the car. If once you rev the engine a bit, the charge light goes off, then Bob's your uncle! You've done it! Congratulations. Go have a Guinness.

If not, then go have a Guinness, come back, and read on.

So What's Wrong With It?

The following things could be wrong with it:

Charging light never comes on

In all likelihood, this means that the circuit from the sense spade (Spade #2) on the alternator to the charge warning lamp isn't complete. Go back and trace through all the connections from spade #2 to the lamp.

Charging light never goes off

Belt is slipping and not turning the alternator pulley

In this case, simply make the belt tighter on the pulley by loosening the adjusting bolt, and using a crow bar to tighten the fit of the belt to the pulley, then tightening the bolt back. You may want someone else to operate the crow bar while you tighten the bolt.

Alternator isn't generating electricity

You can test for this by clamping the ground clip of the test lamp to the negative terminal of the battery, then placing the probe on the 10-gauge red wire to see if it's generating electricity. If it's not, then you may have a bad alternator.

Your Rover is Positive Ground

You didn't convert from positive to negative ground.

Acknowledgments

Many thanks to all those who gave me advice on this, notably Alan Richer (who has a fantastic document on this very topic), John Ousterhout, and John Lattyak, who is my Rover Restoration Spiritual Guide.

Last revised: Thu Jan 1 11:28:14 PST 1998