Maradona, captain of Bilardo's sides that reached consecutive World Cup finals in 1986 and 1990, was handed the job this month, barely a year and a half before the 2010 tournament in South Africa.
"We've got little time, there are 18 months -- less because there are the players' holidays which we must respect," Bilardo, director general of Argentina's national teams, told Reuters on Thursday.
"Then (in 1986) we had four years," he said. "There were young players like Oscar Ruggeri but they got there in good shape."
Bilardo did not want to discuss whether Argentine Football Association president Julio Grondona would grant Maradona's wish to include former defender and captain Ruggeri in his coaching staff.
"I don't know, we'll see," said the 69-year-old. "We have yet to draw up the team, the technical team, I mean. It's not been done."
Bilardo said Maradona's friends Alejandro Mancuso and Miguel Angel Lemme had only been named as his assistants for his coaching debut, a 1-0 win over Scotland at Hampden Park on Wednesday. He did not say whether the pair might be retained.
Grondona has cited personal differences with Ruggeri as standing in the way of him accepting the 1993 Copa America-winning captain on to the coaching staff.
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Maradona's appointment quickly followed former coach Alfio Basile's resignation after a 1-0 defeat in Chile last month which left Argentina third in the South American qualifying group. The top four go through with the fifth-placed team playing off against a team from the CONCACAF region.
The defeat in Santiago meant Argentina had picked up a mere seven points from their last six qualifiers and led to Basile's resignation.
"On the Monday afternoon, Grondona called me, he asked me how Diego was. I told him he looked well, then he talked with Maradona and on the Tuesday afternoon the three of us met and fixed it on the spot," said Bilardo in his characteristic quick-talking manner.
Bilardo will be involved in the coaching and he and Maradona plan to spend a lot of time in Europe.
"We'll come to Europe often, set up an office, because (almost all) the players are here," he said in Glasgow before returning to Buenos Aires.
