wrote 2017/07/10 at 20:33:

We got a similar (identical?) Benz Diesel in the mid-80's together with a modified axle from their test shop for free (Luftsportverein Hameln/Bisperode). The engine and axle still are still in great shape. Not an option for us here in the US and for sure not in Japan.

may be. What I wanted to say is that it's not too hard to fit another
Type of engine into the tost winch than the original one. Truck (Diesel)
Engines should be available also in Japan, and with some search and luck
affordable ones, too.

regards
Werner