6G Celicas Forums

Hi! I hope you nice guys can help me since I don't know anything about cars... I have a 1997 Celica ST 1.8.... it was leaking oil really bad finally it died. The mechanic said I needed a new engine and it was going to cost me 2500$... I don't have that much money!! Sooooo I called around and found 1994 celica 1.8 engine from a celica that was wrecked in the rear, the guy at the junk yard said it would fit.. so I bought it for $300 no problem. Now the mechanic tells me it wont work because it's not the same..... So what's the deal? Any advice will be greatly appreciated. thanks.