need advice on cam belt timing marks for leyland daf 200?

my 200 suddenly stopped a month ago and never started again. the fuel line is good from tank to injectors and all other obvious lines of enqiry have been ruled out (i think!) i then presumed the cam belt had slipped. The top two cogs are correctly syncronised but i was unable to find the marks on the botom cog (crank?) can anyone help me out???