Ingxenye engezansi ye-cylinder block lapho i-crankshaft ifakwe khona ibizwa ngokuthi i-crankcase. I-crankcase ihlukaniswe yaba i-crankcase ephezulu kanye ne-crankcase ephansi. I-crankcase engaphezulu kanye ne-cylinder block zenziwe njengomzimba owodwa. I-crankcase engezansi isetshenziselwa ukugcina amafutha okugcoba nokuvala i-crankcase engaphezulu, ngakho-ke ibizwa nangokuthi i-oil pan. Ipani likawoyela linamandla amancane kakhulu futhi ngokuvamile ligxivizwa kumapuleti ensimbi amancane. Ukuma kwayo kuncike ekuhlelekeni okuphelele kwenjini namandla kawoyela. I-baffle yokuqinisa uwoyela ifakwa epanini likawoyela ukuze kuvinjwe ukushintshashintsha okukhulu kwezinga likawoyela lapho imoto ihamba. Iphansi lepani likawoyela liphinde lifakwe ipulaki yokukhipha uwoyela, ngokuvamile uzibuthe ohlala njalo ufakwa kupulaki yokudonsa uwoyela ukuze umunce izinsimbi zensimbi kuwoyela wokugcoba futhi kuncishiswe ukuguga kwenjini. Kufakwa i-gasket phakathi kwezindawo ezihlangene zamakhrankcase aphezulu naphansi ukuze kuvinjelwe ukuvuza kwamafutha.

I-crankcase iyingxenye ebaluleke kakhulu yenjini. Ithwala amandla adluliswa kusuka ku-rod yokuxhuma futhi iyiguqule ibe yi-torque ukuze ikhiphe nge-crankshaft futhi iqhube ezinye izesekeli enjinini ukuze zisebenze. I-crankshaft ingaphansi kwesenzo esihlanganisiwe samandla aphakathi nendawo wesisindo esijikelezayo, amandla angasebenzi wegesi ezikhathi ezithile namandla angenayo aphindaphindayo, ukuze ukuthwala okugobile kube ngaphansi kwemithwalo egotshwayo kanye ne-torsion. Ngakho-ke, i-crankshaft iyadingeka ukuze ibe namandla anele kanye nokuqina, futhi ingaphezulu lejenali kufanele lingagugi, lisebenze ngokufanayo, futhi libe nokulingana okuhle.

I-crankcase izoguga indawo yokuxhumana phakathi komkhawulo omkhulu wenduku yokuxhuma kanye nejenali ngenxa yamafutha angcolile namandla angalingani ejenali. Uma amafutha equkethe ukungcola okukhulu futhi okunzima, kukhona futhi ingozi yokunwaya indawo yejenali. Uma ukuguga kunzima, kungenzeka kuthinte ubude be-stroke ye-piston phezulu naphansi, kunciphise ukusebenza kahle kokuvutha, futhi kunciphise ngokwemvelo ukuphuma kwamandla. Ngaphezu kwalokho, i-crankshaft ingase futhi ibangele ukusha endaweni yejenali ngenxa yokungagcobi ngokwanele noma uwoyela omncane kakhulu, okungase kuthinte ukunyakaza okuphindaphindayo kwepiston ezimeni ezinzima. Ngakho-ke, uwoyela wokugcoba we-viscosity ofanele kufanele usetshenziswe futhi ukuhlanzeka kwamafutha kufanele kuqinisekiswe.