Vintage Military Porsche Chronograph Repair
Lemania 5100 History and information
Released in the late 1970s, the Lemania 5100 chronograph movement is a robust accurate, and serviceable movement (although not pretty!). It features a smooth action cam-actuated direct-drive sweep minute counter as well as a sweep seconds counter, sub 12 hour counter, sub running seconds hand, and a day/date calendar. Designed to be manufactured economically, most parts are stamped rather than milled.
It also is generous in its use of plastic, or Delrin specifically. This high-tech thermoplastic Polyoxymethylene is durable, resists fatigue, and exhibits a natural lubricity. I’m not a big fan of plastics used in watches, but I have serviced many of these movements and have never observed any major issues related to its use, although I have observed some cracking in the plate that covers the Chrongraph parts under the dial.. The 5100 was used in makes such as Tutima, Sinn, Heuer, and Omega. See CHRONOGRAPHY 4: LEMANIA 5100 for additional information on the Lemania 5100.
Servicing the Orfina Military Porsche
This movement was in good condition and ran very well after service. Its timing report indicated no more than a 7 second deviation between all 6 positions and did not exceed 2 seconds in deviation between the common positions, excellent performance (More on positional adjustment).
The chronograph module is a bit touchy to reassemble and care is taken with the “plastic” parts during cleaning. The case was quite worn and had excessive grime build-up. The case and band were carefully cleaned without further damaging the mat black finish unique to the Porsche.
