Delco Alternator Conversion
for Range Rover Classic


Introduction
Choice of Delco Alternator
Mounting Bracket Adaptation
Wiring
Results
More Information

Photo: Stock alternator (left) and Delco replacement (right), showing difference in mounts.


Introduction
The genuine Marelli alternators for Range Rovers are extremely expensive compared with the usual generic parts. A large number of owners have converted Delco alternators for use in their Range Rover Classics. The first such conversion I was aware of was by John Lewis, who adapted his 1990 RR, and kindly supplied the description and illustrations here.


Choice of Delco Alternator
John used the same Delco as used on his Motorhome -- he just picked one for an 84 GM P-30 chassis. It's a 94 amp unit. To make everything line up he had to modify the top and bottom mounting brackets as shown below.
 

Ashfaq Ali used a 105 amp CAS 130 model 7973 from any late model GM truck with HEI ignition. He also bought a repair harness for it, and had to get a longer belt, but only had to modify (extend) the top mounting bracket.
 

Another owner found an 89 Eagle Medallion Delco alternator bolts right on to the existing brackets with no modifications needed, except for adding a wire to one of the diodes for a tach signal.

Mounting Bracket Adaptation

John made an adapter to convert the stock lower mount to the Delco. It was a simple "H" bracket that mounted on the outside of the stock one, and was spaced so the Delco aligned with the stock pulley. No cutting or welding was needed on the stock lower bracket, but the adjustment arm did have to be extended and re-shaped (see photos below).

John heard of one person who found that the double pulley alternator bolted right on the stock bracket and the outer pulley lined up. Another owner (AJR) reports that  the 89 Eagle Medallion Delco alternator bolts right on to the existing brackets with no modifications needed. You may need an extended tensioner, but AJR ran his for over a year without and had no issues with the belt loosening. You do need to add a wire to one of the diodes for a tach signal - a few minutes with a soldering iron.

Wiring
John found the wiring simple to hook up on the Delco (see photo at right). The heavybrown battery lead attaches to the Delco "Battery" terminal.  Then, for the two spade terminals on the side, the #2 goes to "bat" terminal (John  just took an inline fuse and attached one end to the spade terminal, and the other to the "Bat" terminal.) #1 goes to the warning light, which is the small brown and yellow wire.

The white / slate wire is the tachometer. The alternator John bought already had an extra little terminal on it for the tach. However, if yours doesn't, you can add one. Just open the alternator and attach a wire on one of the three screw terminals. It's hard to describe, but if you open the old Lucas one, and the Delco, you will see that they are similar and it's easy to see how the tach wire connects.

John put the old capacitors back in the same place they came off the Lucas.

One note is that the pulley diameter of the Delco is probably different than the Lucas, so the tach will read a bit off, but it will work. 

Results
John reports that the Delco doesn't seem to put out as much at lower RPMs. However he has never had a problem even off-roading and idling all day, but, when first starting, sometimes had to blip the gas to get it to charge and get the light to go out. One thing he did notice is that the Delco put out about 14.5 volts compared to the 13.5 of the old Lucas. Lights were brighter, and the engine cranked faster and started quicker.

More Information

Alternators New and Rebuilt: Low cost sources for Classic alternators, found by RR owners.
More Delco Alternator installations are described on John Purnell's page
Bosch Alternator (from VW) installation on a Classic
Alternator rebuilding information