WHEN Officer Juan "Ace" Delgado was on patrol near Pat's Steaks in South Philadelphia one night in 1999, he remembered hearing an elderly woman cry out for help.

The woman had dropped her only set of keys into the sewer, and Delgado, now 44, stopped to try to fish them out for her.

"I remember going down there and trying to stretch and saying to myself, 'There goes my uniform,' " Delgado said, smiling.

It's a simple story but one that Delgado, now a community-relations officer in the 3rd Police District, in South Philadelphia, says is an example of why he has been a cop for 14 years.

"People really count on us for even little things," Delgado said. "It's great to be that way, it's great to be counted for."

Delgado, known to everyone as "Ace," got the nickname in high school, and it stuck with him for the rest of his life.

"I was the one that always put my hand up and said, 'I got this answer, I got this answer,' " Delgado said.

"So, then, if someone didn't have the answer, the teacher would say, 'All right, let's see what the ace of the class has to say,' " Delgado said.

These days, people count on Delgado to be their voice when they don't have one, to help make their community better, and to listen to their concerns.

"Ace is basically the direct liaison between the citizens and businesses of the 3rd district and the police command staff here," said Captain Joseph McDowell, of the 3rd district, headquartered at 11th and Wharton streets.

"He is without a doubt the 3rd district's most valuable player," McDowell said. "The level of commitment he has for this community is nothing like I have ever seen before."

That commitment includes directing and developing agendas for community workshops and town-hall meetings, initiating workshops for different ethnic communities on what to do if they're victims of crime, and visiting local schools and playgrounds to educate kids about violence.

"When it comes to kids, I like to make sure that we recognize them," Delgado said. "If you start with the kids today and give them good mentors and good role models, they will see that it's the right way to go."

Another part of Delgado's job is to have regular contact with businesses and business owners in his district, which in large part includes the merchants of the Italian Market, who signed a petition to get Delgado nominated for the George Fencl Award.

Tonight, Delgado, a married father of three, will be honored as a finalist for the award, which the Daily News presents yearly to the officer who most exemplifies Fencl's passion, dedication and courage.

"Ace comes and regularly checks on most of the businesses on 9th Street and sees if there is any way that he can help us," said Charles Esposito, a former cop who works at P & F Giordano Produce on 9th Street and Washington Avenue.

"When it comes to Ace, you can get everything from help with the Parking Authority to the recipe for a good mojito," said Gene Giordano, also of P & F Giordano Produce.

"He makes a mean guacamole too," Esposito said, with a laugh. *