Generator Rebuilding Tips

By Tim Palmer, Green Country Corvair Group

Having recently gone through quite a number of generator to get a few that work properly, I learned a few things about their most common causes of death or failure. Parts for the Corvair generator are available from the Corvair vendors.

• ARMATURES- At least 80% of the armatures I tested were grounded to shaft. It appears the insulation has broken down. The fix for this is either a new armature which is hard find or have the old one rewound. All real Corvair armatures have a left hand nut on the pulley end. Look carefully, many have been replaced with non Corvair ones. The easiest way to remove the nut is with an impact wrench, but CHECK FOR PROPER DIRECTION!
• PULLEY END FRAME- A good many of the ears are broken off at the mount. It appears to me this comes from not properly mounting the opposite end. The picture below from the parts book has a better view and description of how it mounts. All Corvair ones I have seen are aluminum. Some steel after market ones were used by rebuilders.
• COMMUTATOR END FRAME- A few of these have had their mounting ear broken off. I'm not sure how. These were also all aluminum, although some steel aftermarket ones were used by rebuilders.
• COLLAR- Wear on this part can cause excessive end play, which will lead to premature failure. There should be very little end play on a properly rebuilt generator.
• BRUSHES- Cheap to replace. They are not special and were used in many GM generators, so they are easy to find.
• BEARINGS- The pulley end used a ball bearing. The other end uses a bushing. I would replace both. The pulley end especially since it takes most of the load. This is a common bearing. It is the same one used in the later alternators.
• PULLEYS- Real Corvair pulleys have a “H” stamped on the back side. The blades are different from a regular generator since the Corvair generator turn backward to everything else.
• OILING- Remember to oil the commutator bearing as shown in the shop manual. If you have replaced the pulley end bearing with a new one it is probably a sealed bearing and does not require oiling.
• STORAGE- If you need to store the generator before you put it on your Corvair, it is a good idea to put in a large plastic bag with one of those moisture absorbing bags. The bag will keep spiders from building homes in your generator. The moisture absorbing bags will help prevent any rust from forming.