Defense Secretary Caspar W. Weinberger appointed a career Pentagon official to the new post of "procurement czar" yesterday, giving him responsibility over the beleaguered process of buying the nation's weapons.

In naming James P. Wade Jr. as the first assistant secretary for acquisition and logistics, Weinberger chose an official who has detailed knowledge of the procurement system and the loyalty to the administration to contain the embarrassing procurement scandals that have become public in recent months.

Wade has handled procurement matters for most of his 18 years in the Pentagon. For the past seven months he has been acting undersecretary for research and engineering of weapons systems.

His appointment triggers a controversial reorganization plan unveiled by Weinberger in January, which will consolidate the tasks of buying and maintaining weapons and spare parts and managing the logistics system and facilities.

Opponents have criticized the reorganization as a public relations stunt by Weinberger to avoid more serious revisions in the Pentagon's procurement process, which has allowed such contractor abuses as charging $659 apiece for aircraft ashtrays.

Administration supporters believe the procurement scandals have undercut the president's political consensus for a strong defense, and given congressional doves ammunition in their fight for deep cuts in military spending.

A Pentagon statement yesterday said the reorganization will "strengthen controls, clarify responsibilities and provide increased emphasis on the management of acquisition and logistics programs."

Wade, 54, whose appointment had to be approved by the White House, brings years of weapons management experience to the new position. Since 1981, he has served as principal deputy undersecretary of defense for research and engineering and as assistant secretary for weapons development and support.

Despite his background, Wade reportedly was not Weinberger's first choice.

According to administration officials, the secretary initially recommended Pentagon Inspector General Joseph H. Sherick for the post, apparently hoping to draw on his image as an aggressive investigator of contractor abuse.

Officials said key members of Congress blocked the appointment of Sherick, whose office is investigating criminal allegations against nine of the nation's top 10 defense contractors.