▁one ▁of ▁them ▁rot ated ▁in ▁the ▁opposite ▁direction ▁to ▁the ▁other ▁two . ▁ ▁Being ▁an ▁opposed - p ist on ▁design ▁with ▁no ▁in let ▁or ▁exhaust ▁val ves , ▁and ▁no ▁ability ▁to ▁vary ▁the ▁port ▁positions , ▁the ▁D elt ic ▁design ▁arranged ▁each ▁c rank sh aft ▁to ▁connect ▁two ▁adjacent ▁p ist ons ▁operating ▁in ▁different ▁cyl ind ers ▁in ▁the ▁same ▁plane , ▁using ▁" f ork ▁and ▁bla de " ▁connecting ▁ro ds , ▁the ▁latter ▁an ▁" in let " ▁p ist on ▁used ▁to ▁open ▁and ▁close ▁the ▁in let ▁port , ▁and ▁the ▁former ▁an ▁" ex ha ust " ▁p ist on ▁in ▁the ▁adjacent ▁cyl inder ▁to ▁open ▁and ▁close ▁the ▁exhaust ▁port . ▁This ▁would ▁have ▁led ▁the ▁firing ▁in ▁each ▁bank ▁of ▁cyl ind ers ▁to ▁be ▁ 6 0 ▁degrees ▁apart . ▁However , ▁it ▁was ▁decided ▁to ▁ar range ▁that ▁each ▁cyl inder ' s ▁exhaust ▁p ist on ▁would ▁lead ▁its ▁in let ▁p ist on ▁by ▁ 2 0 ▁degrees ▁of ▁c rank sh aft ▁rotation . ▁This ▁allowed ▁the ▁exhaust ▁port ▁to ▁be ▁opened ▁well ▁before ▁the ▁in let ▁port , ▁and ▁allowed ▁the ▁in let ▁port ▁to ▁be ▁closed ▁after ▁the ▁exhaust ▁port , ▁which ▁led ▁to ▁both ▁good ▁sc av eng ing ▁of ▁exhaust ▁gas , ▁and ▁good ▁vol um et ric ▁efficiency ▁for ▁the ▁fresh ▁air ▁charge . ▁This ▁required ▁the ▁firing ▁events ▁for ▁adjacent ▁cyl ind ers ▁to ▁be