USA version 1981-83 M116 engines used a single row chain instead of a duplex version.
MB went back to the duplex chain in 1984.
There aren't any isssues with the duplex chain other than "stretch" at 100K+ miles.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
42 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)