The OM 636 in your 319 should be fairly similar to the engine used in the Ponton style 180D, as well as the earlier 170DS and SD. You might want to check out the Ponton website noted below.

http://www.mbzponton.org/

Ps: those are sooo much cooler than a VW bus!!!

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150