TECHNICAL REVIEW OF THE IWC MARK XII MOVEMENT
Posted by Jack Freedman on March 24, 1998 at 11:21:15:
The Mark XII has been a big success for IWC as it is designed as a pilot watch resembling their legendary Mark XI and is also in size, weight, and readable clarity a great watch for either dress or sport. The styling of the dial, hands and case is crisp and clear. Whether you have one with the buffalo strap or the metal bracelet, itís a delight to wear.
However, most people are unfamiliar with the mechanical automatic movement hidden inside its case beneath a soft iron inner cover from one side and a sapphire glass on the other side with a screw-down crown in between.
I have been asked by to share my technical knowledge and experience to explain the specific finish and enhancements of the Mark XII movement and how it relates to other similar movements. There seems to be confusion among watch buffs about the origin of the movement. Let me begin by saying this movement is based upon JLCís calibre 889/2 – a 36-jewel fast beat automatic movement vibrating at 28,800 beats per hour.
To the best of my knowledge, JLC assembles these movements in their factory for its sister company, IWC, under IWC’s own calibre 884/2, a different calibre number designating technical and/or finishing modifications. The 884/2 has 36 jewels and the finish is a flat matte nickel plating with no decorations on any of the bridges or rotor. Unlike the same basic movement used by IWC in other models such as their Ingenieur, where the rotor is in 21 ct. gold or platinum, the Mark XII rotor is also nickel plated and plain to match the rest of the movement plates.
The movement, although of exceptional high-grade quality, requires careful maintenance and must be kept in fresh condition to assure top performance for accuracy and reliability. A sluggish movement, one whose timepiece has been kept unwound for a few months, may result in insufficient winding due to a lazy or sticky rotor and inaccurate timekeeping due to poor amplitude of the balance wheel.
A complete maintenance and service, covering an overhaul (cleaning, oiling and regulating) and reseal with watertest, is recommended once every three years or sooner if watch hasnít been used for an extended period of time. Since this high-grade movement must be very precisely oiled (not too little, not too much) with the proper lubricants, it is suggested that the Mark XII be serviced by an authorized service center.
SUPERIOR WATCH SERVICE INC.