Wouldn't it be great to convert the 912 generator to an alternator?

How about a 911 alternator?

Bernie Bergmann has announced an alternator kit for 356 ABC and 912 engines. It is now available but there are few details. We saw a similar conversion on a very nice looking 1958 356 Speedster at the Palo Alto Concours last July.


This 160 hp blue-printed VW engine was built for the owner, Richard Downing, by CB Performance Farmersville, CA (North of Fresno). I really like the look of this engine.

Note: There are other issues with such a conversion.
  • The oil cooler must be moved off the engine. This is a problem for the VW engines also, evidently solved with an off board cooler and an adapter plate with pipe fittings.
  • The oil filter has to be moved off the engine.
  • Gas lines have to be rerouted.
  • Depending on the model year, may cause heating system issues.
  • The throttle linkage has to be redone. The VW parts should help.
  • The coil must be remounted, normally to the band holding the fan assembly.
  • The pulleys for the fan belt may need changing to get the proper speed for the generator.
  • One may want to add some instrumentation to monitor cylinder head temperature.
  • There is some discussion on the WEB about the optimum number of blades on the fan. There must be a trade-off of cooling vs horsepower loss.
  • Would loose originality points at your next concours.
  • May offend purists.
  • Expensive. Probably would not get back the cost on resale.
  • It may void your warranty (Ha).

On the plus side:
  • More even cooling to the cylinders
  • Cooler running engine which may increase engine life
  • Alternator - providing more reliable electrical power using standard components. Generators no longer available - they must be exchanged or rebuilt.
  • The 'sound' of the engine is enhanced according to some reports. Part of the distinctive sound of a 911 is the fan design.

Bernie supplies a new crank pulley, a block off plate for the mechanical fuel pump, an electric fuel pump, a low rise oil cooler block off plate, and an alternate oil filler with his VW kits.

Why is an electrical fuel pump part of Bernie's VW kits?

Here are other sites that advertise 911 fan kits:

Upgrade to the 1968 generator

There were two generators supplied with the 912, one of 350W and the second, starting in 1968, the 420W. The latter is the same size as one of those for a VW. Later models of VW converted this to a alternator so it should be possible to change the generator in later 912 engines to the VW alternator.

Since the diameter changed, the stand for the generator had to change also. It should also be possible to upgrade to the parts required for the larger generator on the older engines. Here are the part numbers for parts that changed from the 350W to the 420W generator.

 Part Number Description
 616.101217.00 Generator stand for generator 420W.
 539.01.125 Gasket for generator bracket
 547.09.303 Nut for fan
 616.106.023.00 Fan
 616.106.337.00  Cover plate
 616.106.201.00 Hub for fan
 616.106.339.00 Reinforcement flange for fan cover
 616.106.024.00 Cover for fan housing

The VW stand is not interchangeable with the Porsche one. The hole pattern for the connection to the case is square for the VW and rectangular for the Porsche.

Performance Air Kit

Cars with air conditioning may have alternators using a special stand. Porsche Air, now Performance Air, 1885 Santa Cruz St. Anaheim, CA 92805. (714) 634-9184 made an alternator kit for use with their air conditioners. A call to them confirms the kit was made, however, due to lack of sales, it was discontinued several years ago and there is no more inventory.

Add on Alternator

Another option is to mount a small alternator off to the side of the generator and add the appropriate belts and pulleys to operate it. Remove the brushes from the existing generator to allow it to operate the fan with minimum drag. J.C. Whitneys might be a good place to order the alternator.
Last modified: Tue, 18 Dec 2001


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