Terms for subject Engines containing A,A,A,A

English	Russian
a valve burns	клапан прогорает
middle of a stroke	середина хода (поршня)
remove a backlash	выбрать люфт (translator911)
scavenge a cylinder	продувать цилиндр (Scavenging is equally important for both two-stroke and four-stroke engines. Most modern four-stroke engines use crossflow cylinder heads and valve timing overlap to scavenge the cylinders.)