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B44 Alternator Repair

Posted: Thu May 30, 2019 9:44 am
by Ubert767
I have a Lucas alternator rotor (19- 8019) with a loose central boss. Please can anyone expand on the rotor repair that "RR" briefly describes in his book. Does it matter which side ( inboard or outboard ) of the rotor boss is machined away in order to reveal the worn components?
Thanks,
Rob

Re: B44 Alternator Repair

Posted: Thu May 30, 2019 10:12 am
by kommando
It goes in the bucket and you buy a replacement.

I can't find the book but from memory Rupert Ratio's fix is not for a rotor that's disintegrating but for a rotor loose on the soft B25 crank mainshaft. Its soft as the big end is a shell bearing and the crank is not hardened, the built up cranks have the hardened shafts.

Re: B44 Alternator Repair

Posted: Thu May 30, 2019 5:29 pm
by minetymenace
Not in the bucket! Magnets are useful around the shop, stick it on the drill press to hold the chuck key or something....

but yes, buy another, there's one on ebay for £9 and rotor + stator for £50....or new for about £73 (feked.com and elsewhere)

Re: B44 Alternator Repair

Posted: Thu May 30, 2019 5:35 pm
by Ubert767
My thanks to both for that advice.
Rob

Re: B44 Alternator Repair

Posted: Thu May 30, 2019 8:30 pm
by Jeff K
minetymenace wrote:
Thu May 30, 2019 5:29 pm
Not in the bucket! Magnets are useful around the shop, stick it on the drill press to hold the chuck key or something....

but yes, buy another, there's one on ebay for £9 and rotor + stator for £50....or new for about £73 (feked.com and elsewhere)
Used alternators are cheap on Ebay, And if you need large very strong magnet. Take a ride on trash day, Microwave ovens have a large and very powerful magnet in its core that is easy to get at.

https://www.youtube.com/watch?v=kyVjWhM2M8U

Jeff

Re: B44 Alternator Repair

Posted: Fri May 31, 2019 6:10 am
by Canberra
I believe the rotors that were prone to failures on earlier engines were replaced by a modified unit. So only replace with a new rotor and don't look at a second hand one. I think the magnets are stronger as I gather the originals loose magnetism over time and so alternator doesn't produce as much power. Others may wish to comment on these theories.

John

Re: B44 Alternator Repair

Posted: Fri May 31, 2019 8:12 am
by minetymenace
Think your theories are sound John...

Re: B44 Alternator Repair

Posted: Fri May 31, 2019 9:37 am
by BSA_WM20
[quote=Canberra post_id=77941 time=1559279458 user_id=27]
I believe the rotors that were prone to failures on earlier engines were replaced by a modified unit. So only replace with a new rotor and don't look at a second hand one. I think the magnets are stronger as I gather the originals loose magnetism over time and so alternator doesn't produce as much power. Others may wish to comment on these theories.

John
[/quote]

yes magnet loose power over time
As for the deceased unit, remove the magnets as already mentioned very handy.
Then clean the alloy off the boss and pop it in your box of "BSA Special Tools"
When you or one of your friends finds an unknown rattle from the primary that seems louder at idle, substitute your plain boss for their rotor.
Strange sound goes away = loose magnets in rotor.