Nowhere did you say the old guys code didn't work, had serious bugs that weren't being fixed, or was noticeably behind the rest of the team according to the project schedules. Until that happens, and as long as the old guy is solving problems with his skill set, management may well consider your "good coding" criteria to be bad for the company, thus making you, not the old guy, the troublemaker for suggesting changing what works. Businessmen have been burned by too many trendy sounding academic fads, such as all the good coding practices recommended here.
Wait till you can out-code him, solve major problems he can't, and get promoted above him (or he dies or retires). Even if his smelly pile of code crashes and burns, if he can tape it back together faster (running) than you can rewrite it (feature complete), he's the hero, and you're the troublemaker.