By Marina Malenic

LONDON–The two rival engine manufacturing teams angling for work on the Pentagon’s F-35 Joint Strike Fighter continued their war of words at the world’s largest air show outside London as the issue awaits final resolution in Washington.

United Technologies Corp.‘s [UTX] Pratt & Whitney unit, manufacturer of the primary F135 engine for the effort, is actively lobbying lawmakers to become the sole engine supplier for the largest weapons acquisition program in Pentagon history. However, Pratt & Whitney President David Hess asserted this week that his rival’s lobbying expenditures are much greater.

Hess told reporters during a July 20 briefing at the Farnborough Airshow that General Electric [GE] and Rolls-Royce, the industry team producing the F136 alternate engine for the F-35, is spending “orders of magnitude” more on lobbying than his company has done.

In a separate briefing later that day, Jean Lydon-Rodgers, president of GE Aviation’s military unit, characterized Hess’ estimation as “unfair” and said GE’s massive lobbying encompasses issues beyond the F136.

At stake is over $100 billion of work if the Defense Department and several U.S. allies purchase over 2,000 of the jets as planned.

Alternate engine supporters in Congress have continued funding the F136 for four years despite Pentagon objections. Defense Secretary Robert Gates has repeatedly said that he will recommend that President Barrack Obama veto any defense funding bill that contains money for the second engine. Obama has been largely silent on the issue in recent months, though during his first year in office he singled out the F136 program as a prime example of “government waste.”

GE and Rolls officials said they hope for a final resolution this year.

The House defense appropriations subcommittee is slated to take up the issue during it markup of the FY ’11 defense spending bill next week.

Second engine supporters in Congress have long argued that the precedent of the so-called F-16 “engine wars” of the 1980s helped to drive down costs significantly.

GE and Rolls executives here said their effort conforms to the Obama administration’s calls for competition on weapons acquisition programs.