Different winding behaviour: BP 5004 vs Port Auto

Hi all, I have a BP 5004 and Port Auto. Although they're based on very similar movements, if I have to hand wind the Port Auto, I can't wind it after the power reserve needle is on 7 days - the winder physically locks, and the movement becomes unwindable.

For the BP, I can keep winding it even though the needle is on 7 days; there's no change in resistance and no change in sound.

Both watches keep good time, and wind themselves when I'm wearing them (interestingly, the BP is more efficient at this than the Port Auto), so I'm not convinced there's a fault with either.

The BP is about a year newer than the Port Auto, so there may be some well known movement changes that explain this.

Can anyone comment on the different behaviour between the two watches? Should I be concerned, or should I get on with my life and enjoy two fine IWC watches?

Many thanks for reading and any information offered.

May be...

Port Auto has the calibre 51010, 44 jewels movement. You can confirm this by looking the crystal back of the watch. And the BP probably has the newer calibre 5XX11 with 42 jewels wich has improved automatic winding system. You can research in the archives about the differences of the calibres, there is a lot of information.

But hand winding frecuently and putting force on the crown of these complex mecahnical fine movements are not a good ideas.

Why hand wind it?

Why hand wind a 7 day watch beyond getting it started? Wear and wind it by natural movement, that's what autos are all about! A few turns maybe to start it but you are not gaining anything by manually winding a 40hour or 7 day watch to fully wound. Besides a watch with PR and how quickly it gets fully wound is a fair indicator of the amount of exercise you do! So a quick glance every now and then will be more of a treat than just "what's the time?"

The 5001 should 'slip' too (more)...

... once it has reached 'full reserve'.

ALL automatic watches will have some form of a mechanism that 'slips' in order to prevent the watch from 'overwinding'. My Port.Auto certainly does, with a clearly audible ticking sound.

So, I guess you need to have your PortAuto checked if it really blocks at full PR.

Despite what others say: I think it is perfectly ok to manually wind an automatic watch! 7 days is really fantastic, but I also like it to be the 'higher regions' of PR (and theoratically it should be more accurate).

Regards,

Bob

The 5001 should 'slip' too (more)...

I do not wind my BP all the way as i like to see the pr increase when i am wearing it. It gives me another reason to look at my watch !