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dickk · 06-15-2007, 01:57 PM

6/15/07

Thanks for your comments. I have been told that the alternator was originally designed for 100 amp and then "re-labled" for 140A. The second alternator did expire in the bearing. I still have the core for the third failed alternator. As Joe suggested the front part of the alternator is aluminum and bolted to the engine for a ground connection. The regulator is contained on the back aluminum part of the alternator and is separated by the laminated iron stack of the alternator. However, there are three bolts that tie the front and rear aluminum sections together which should electrically bridge any corrosian areas. I did measure the resistance between the front and back using a digital multimeter = less than 0.1 ohms. I'm pretty sure the failure this time is in the regulator. I intend to dig it out and measure the components.

The alternator does run hot. Just after the recent failure it was too hot to keep my hand on it even though the car was only in operation for 5 minutes before the failure.

Another possible cause is the positive battery cable that ties to the side mount terminals of the battery. The washer stack under the bolt was not assembled correctly so that the cable could be rotated even though the bolt was as tight as possible.

In any case, thanks for your suggestions.

06-15-2007, 01:57 PM	#4 (permalink)
dickk Junior Member Join Date: Jun 2007 Posts: 3	Comments on Cutlass eating alternators 6/15/07 Thanks for your comments. I have been told that the alternator was originally designed for 100 amp and then "re-labled" for 140A. The second alternator did expire in the bearing. I still have the core for the third failed alternator. As Joe suggested the front part of the alternator is aluminum and bolted to the engine for a ground connection. The regulator is contained on the back aluminum part of the alternator and is separated by the laminated iron stack of the alternator. However, there are three bolts that tie the front and rear aluminum sections together which should electrically bridge any corrosian areas. I did measure the resistance between the front and back using a digital multimeter = less than 0.1 ohms. I'm pretty sure the failure this time is in the regulator. I intend to dig it out and measure the components. The alternator does run hot. Just after the recent failure it was too hot to keep my hand on it even though the car was only in operation for 5 minutes before the failure. Another possible cause is the positive battery cable that ties to the side mount terminals of the battery. The washer stack under the bolt was not assembled correctly so that the cable could be rotated even though the bolt was as tight as possible. In any case, thanks for your suggestions.