On a PA-28-151, we had an alternator fail. It first presented as a low charging rate and then became more of a wandering needle on the Amp meter. The needle would bounce between 0-20 amps and eventually 0 amps. We discovered that the front crank seal was leaking and it ended up soaking the alternator in oil. I removed the alternator and removed the brushes to find the worn and covered in dirt and oil. So we decided to replace the alternator with another Chrysler, a decision we will soon regret. While the alternator was removed, we replaced the crank seal, all of the main battery, starter, airframe ground and starter ground cables using a Bogarts cable upgrade. We also replaced the starter solenoid, the field wire terminals and alternator output cable. In short, it is a completely new starting and charging system minus a Skytek starter with about 700 hours in it.
Here is our new issue. After replacing all of the aforementioned components, the test runup was all good. System was charging great and engine cranks like it never had before. On the test flight, just after wheels up, the alternator stopped charging. So we landed without incident and as soon as we exited the runway the alternator began to charge again. So we took off again to confirm the failure and low and behold if failed again. So we taxied back and removed the cowlings to inspect. Everything was in order, no loose terminals, oil contamination, loose capacitor, etc. We suspected maybe the field wire was the culprit so we checked for opens from the alternator to the switch and all was well even while wiggling the wire. So we moved on to the field ckt breaker and replaced that along with a new alternator output breaker. Ran it up, and same issue. This time we could get it to fail by cycling the field ckt switch. If we had the engine above 1000 rpms and turned off the field ckt switch and then back on, the alternator would not charge. It would sometimes fail during a normal runup, and then come to life once we reduced to idle and then back up to 1000 ish rpms. Sometimes it would fail and would not charge again unless we shutdown the engine, and immediately start it back up. It would charge with no issue until after a takeoff. We did get it to stay charging for 1.3 hour flight, but the symptoms return during the next flight.
So, we are pretty certain that the alternator is the culprit. We purchased a Falcon OH Chrysler for Aircraft Spruce. We toyed with upgrading to a Plane Power, but opted to wait until the next engine overhaul as we planned to do the 180 upgrade. I have seen some post about Chrysler alternators engine in correctly overhauled where the tech uses too much grease where the armature spins which causes it to break contact. I feel that this might be true for us.
Thoughts? Thank you in advance!
Here is our new issue. After replacing all of the aforementioned components, the test runup was all good. System was charging great and engine cranks like it never had before. On the test flight, just after wheels up, the alternator stopped charging. So we landed without incident and as soon as we exited the runway the alternator began to charge again. So we took off again to confirm the failure and low and behold if failed again. So we taxied back and removed the cowlings to inspect. Everything was in order, no loose terminals, oil contamination, loose capacitor, etc. We suspected maybe the field wire was the culprit so we checked for opens from the alternator to the switch and all was well even while wiggling the wire. So we moved on to the field ckt breaker and replaced that along with a new alternator output breaker. Ran it up, and same issue. This time we could get it to fail by cycling the field ckt switch. If we had the engine above 1000 rpms and turned off the field ckt switch and then back on, the alternator would not charge. It would sometimes fail during a normal runup, and then come to life once we reduced to idle and then back up to 1000 ish rpms. Sometimes it would fail and would not charge again unless we shutdown the engine, and immediately start it back up. It would charge with no issue until after a takeoff. We did get it to stay charging for 1.3 hour flight, but the symptoms return during the next flight.
So, we are pretty certain that the alternator is the culprit. We purchased a Falcon OH Chrysler for Aircraft Spruce. We toyed with upgrading to a Plane Power, but opted to wait until the next engine overhaul as we planned to do the 180 upgrade. I have seen some post about Chrysler alternators engine in correctly overhauled where the tech uses too much grease where the armature spins which causes it to break contact. I feel that this might be true for us.
Thoughts? Thank you in advance!
