The Elan came equipped with a Lucas DC generator and regulator. This system is adequate and essentially reliable, and is simple and "user-friendly" to work on. These positive thoughts about the generator set-up beg the question; why convert? Simply, an alternator can do a better job of keeping the battery charged. I imagine that most conversions occur as a result of failure of the existing system. I have done this conversion twice, and it was failure that prompted me both times.

SELECTION OF ALTERNATOR

The key factor here should be availability. I feel that a Lotus should be upgraded in the interests of reliability and serviceability. What good is a Lucas generator if it fails in Mendocino or Desert Center? So, for these fears I suggest a popular brand, such as Chevy, Ford or Chrysler.

An obvious choice would be to use a set-up from a 1600cc Capri or Pinto. The Capri system is Bosch, and hence will cost more and not have goo availability. The Pinto would be a good choice, but it has a separate regulator. For simplicity, I suggest a built-in solid state regulator. The American makers switched over to built-in regulators in the late 60's and early 70's.

Another factor is size. The Elan engine compartment is cramped as it is, and there is not much room around the generator. The steering column is very close (LHD). When I did my first conversion, a parts store was good enough to let me go through their alternators. The smallest I found, with a built-in regulator, was the Chevy. I did my shopping 5 years ago (1979), and quite possibly there are smaller units out now. The Chevy fits, but it is tight. (Ed comment: Others have successfully used alternators from Nissan & Toyota)

The final factor is cost. Here, the American units win hands down. A rebuilt unit can be found for less than $50 if you shop around. A core charge of $15 or so will be charged in addition. Chances are they will not take the Lucas generator in exchange. A used unit form a junk yard will be even cheaper.

Based on these criteria I recommend using Chevy. They are universally available, they have a built-in regulator (which incidentally, can be purchased separately for repairs, $15), they are cheap, and they fit. One final thought on selection. Chevy makes these units with the electrical connections at three different locations. Get the connections at 12 o'clock (or opposite the bottom pivot).

INSTALLATION

In my first installation I had tremendous problems with the bottom mount. The geometry was fine, but the factory bracket wasn't strong enough for the heavier alternator. The first step therefore, is to get a 1600cc Pinto bottom mount. The Pinto mount is almost laughingly over-engineered, but it is bulletproof. A junkyard should be able to supply this for $5 or so. (1600cc Pintos are not in great demand.) Get the mounting bolts with the mount. Remember to use Loctite on the threads when installing. It is a big job to get to these bolts, and the Twin Cam does tend to vibrate nuts loose.

For the bottom pivot bolt I suggest 3/8 inch threaded stock. All nuts for this should be Nylock or be equipped with lock washers (see sketch). Selection of the fan belt is tricky. The alternator / steering column fit is tight, and only about two inches of movement is available. Make sure you have transportation to the parts store to exchange the belt if you guess wrong on the first go around. On one of my applications the alternator must be free from the bottom pivot to get the fan belt on. If the clearance is too tight on your car, I suggest two changes. First, check the condition of the motor mounts. These wear out, and the design of the mounts prevent the engine from falling out (which would make the worn mount obvious). If the condition of these are in doubt, install new ones: they are not very expensive. If you still have clearance problems, I suggest you try using a carb side engine mount on the exhaust side. I have not tried this, and it could possibly cause other problems (such as, will the cam cover touch the hood).

The tension adjuster bracket is simple. Lotus makes a bracket that is perfect for the job. Remember to leave some slack in the belt. Excessive tension (or even normal tension) will eat the water pump bearings and replacement is very difficult. Since the alternator puts out more current, you can afford to allow a little more slack in the belt tension.

The final step is to wire it all up. There are only three connections on the Chevy alternator: Field: Output; and warning light. Run a wire from the fuse box to the field (this is so the regulator knows what the electrical system needs), extend the warning light wire to the alternator, and run a heavy wire from the hot side of the starter solenoid to the alternator Output. Very simple. Removing the generator and regulator leaves many wires. Some can be removed, and some will need to be connected together. A review of the wiring diagram should explain what each wire does. If you have positive ground you will have to change your polarity. Items here are the tach, the radio and the coil.

Original article published at Golden Gate Lotus Club