Speedex750
Member
- Posts
- 90
- Location
- North East England
Hi,
I normally hang out on the Discovery forum for my D4 with occasional forays into the Defender world when helping my youngest with his TD5 110. I do have other cars, and as you can imagine - problems.
Latest is an alternator problem on an Austin 7. Yes I know they're supposed to have a dynamo but they were 6v, crap at charging and fragile. A company made some 'look alike' 12v alternators for these as a retrofit which is what I've got. It is more complex to change out compared to a normal belt driven one as it is gear driven with the distributor being driven from the other end, which also makes it a pain in the arse to remove and refit/set up. The company have stopped making it and withdrawn all support.
Mine did originally work and nicely balanced the ammeter reading but then the red light started flickering and eventually became always there.
I've stripped it down (a few times in fact) and cant find a fault. Can I draw on the enormous collective experience of those on this forum? Can you help please, am I missing something stupidly obvious?
The rotor coil has continuity at 4 ohms with good continuity out through the sliprings and brushes (which I manged to renew with a generic brush box item). The stator coil tests out similarly, though I haven't split out the separate coils in it to test individually. The diode pack has continuity in one direction and a very large resistance in the opposite direction. I've tried different regulators, cutting and grafting them from proprietary items (but can't work out which way to connect the two live wires - but neither alternative brings the alternator back to life). The alternator has a good earth to the engine and back to the battery.
If there's something down I'll have to either fix it myself or graft in a spare from something else though the rotor, stator and diode pack are very bespoke to the very small 3.5'' diameter body.
Am I missing something or not testing an aspect correctly and meaningfully?
Can you please advise how to test out each of these components?
Thank you, Dave
I normally hang out on the Discovery forum for my D4 with occasional forays into the Defender world when helping my youngest with his TD5 110. I do have other cars, and as you can imagine - problems.
Latest is an alternator problem on an Austin 7. Yes I know they're supposed to have a dynamo but they were 6v, crap at charging and fragile. A company made some 'look alike' 12v alternators for these as a retrofit which is what I've got. It is more complex to change out compared to a normal belt driven one as it is gear driven with the distributor being driven from the other end, which also makes it a pain in the arse to remove and refit/set up. The company have stopped making it and withdrawn all support.
Mine did originally work and nicely balanced the ammeter reading but then the red light started flickering and eventually became always there.
I've stripped it down (a few times in fact) and cant find a fault. Can I draw on the enormous collective experience of those on this forum? Can you help please, am I missing something stupidly obvious?
The rotor coil has continuity at 4 ohms with good continuity out through the sliprings and brushes (which I manged to renew with a generic brush box item). The stator coil tests out similarly, though I haven't split out the separate coils in it to test individually. The diode pack has continuity in one direction and a very large resistance in the opposite direction. I've tried different regulators, cutting and grafting them from proprietary items (but can't work out which way to connect the two live wires - but neither alternative brings the alternator back to life). The alternator has a good earth to the engine and back to the battery.
If there's something down I'll have to either fix it myself or graft in a spare from something else though the rotor, stator and diode pack are very bespoke to the very small 3.5'' diameter body.
Am I missing something or not testing an aspect correctly and meaningfully?
Can you please advise how to test out each of these components?
Thank you, Dave
