A federal prosecutor asked jurors Monday to convict three executives of Teledyne Electronics, describing them as men who chose words carefully in taped telephone conversations but who knew surely of a company consultant's scheme to bribe a senior Navy engineer.

"They knew what was getting done," Assistant U.S. Attorney Jack Hanly said in closing arguments at the trio's criminal trial. "They didn't know all of the details, but they knew more than what they wanted to admit they knew."Lawyer Mark Tuohey, arguing for the defense at the first trial in the massive Pentagon corruption scandal, countered by depicting the executives as entirely in the dark about the scheme that already has led to guilty pleas by industry consultant William Parkin and three others.

"The prosecutor said this is a case about bribery, cheating and lying. Ladies and gentlemen, this was," Tuohey said, accenting the past tense, "a case about bribery, cheating and lying . . . This was a case that was, rather than a case that is."

The three suspended executives of the company in Newbury Park, Calif., a subsidiary of Teledyne Industries Inc.- Vice President George Kaub, former Comptroller Eugene Sullivan and current Comptroller Dale Schniitjer - each is charged with conspiracy, bribery and fraud for allegedly scheming to rig the 1987 award of a Navy electronics contract worth as much as $24 million.

Kaub also is charged with making false statments to the government and denying that the company paid an illegal contingency fee to anyone in connection with the contract.

Prosecutors played three hours of tapes of wiretapped conversations for the jury and called government witnesses.