Originally Posted by Wharbone

D's are the SOHC engines. D16Z6 and D16Y8 are the vtec versions. The number represents your displacement. 1.6L

B's are DOHC engines. B16A is a 1.6L DOHC vtec motor. B18C is 1.8L DOHC vtec motor. B18B is a 1.8L non-vtec.