The Senate voted 64 to 32 yesterday to override the recommendation of its Foreign Relations Committee and grant Turkey $50 million in military aid instead of loaning the same amount as a credit.

In practice the distinction was modest, but both opponents and proponents of the idea-including the Carter administration which pushed it said the symbolism was important.

The question produced a rare example of intensity argued Senate debate in which friends of Greece and austerity-conscious conservatives opposed the grant to Turkey while a bipartisan coalition of senators defended it as a necessary symbol of concern for a troubled NATO ally.

Senators often cited the same evidence for contrary positions. For example, several opponents of the proposal said Turkey should not be rewarded just days after announcing that it would have to check with Moscow before approving U2 flights over Turkey to monitor the strategic arms limitation treaty (SALT). Several proponents said Turkey's importance to the monitoring of SALT II was a reason to support the grant.

The principal proponent of the pro-Turkish gesture was Majority Leader Robert C. Byrd (D-W. Va.). Byrd spent most of last week organizing lunches, meetings and briefings for colleagues and pressing the cases for Turkey.

Carter administration lobbyists who worked with Byrd were not sure as late as Monday night that they had the votes to beat the Foreign Relations Committee, the pro-Greek lobby and others who opposed the outright grant to Turkey. But the majority leader showed his strength today, carrying the vote 2 to 1.

Some Senate sources speculated that Byrd made an especially strong effort in part to demonstrate that the vote on Rhodesian sanctions last week was not a true measure of his influence in the Senate. The Senate voted 75 to 19 on May 15 to recommend the lifting of sanctions against Rhodesia despite Byrd's preference for another proposal.

Yesterday's debate provided another occasion for senators to display the chronic split over U.S. policy in the Eastern Mediterranean issue that has persisted for years-to the detriment of U.S. diplomacy, according to the State Department and the last two administrations.

The Foreign Relations Committee had sought to find a compromise path this year that would avoid another eruption of Greek-Turkish animosities on the Senate floor. The committee endorsed the Carter administration's total package of economic and military aid for Turkey, which totals $451 million, making Turkey the world's third-largest recipient of U.S. aid, after Israel and Egypt.

But the committee made one change, shifting a proposed $50 million in military assistance from a grant to a long-term loan on extremely favorable terms, including a 10-year grace period before the first payment.

The administration sought to restore the $50 million grant as part of its campaign to improve relations with Turkey. The Turkish government is struggling with hugh external debts, a stagnant economy and anarchic conditions at home that have provoked the government to impose martial law in many areas.

In comments typical of the opponents of the grant, Sen. Edward M. Kennedy (D-Mass.), said the United States should not be doing the Turks special favors, because Turkey has blocked reintergration of Greece into NATO, refused to relinquish occupied territory on Cyprus and withheld agreement for the use of its territory for SALT verification.

In a typical response, Sen. Henry Bellmon (R-Okla.), said the United States too easily gets "bogged down" in petty disputes between neighboring countries (i.e., Turkey, Greece and Cyprus) and loses sight of "the big picture." Bellmon said support for Turkey was crucial for the future of NATO and American interests generally.

The foreign aid authorization bill, approved by the Senate last night, 69 to 21, has a total potential value of $4.4 billion, but calls for appropriations this year of only $2.8 billion.

The House has yet to act on the Turkish aid question.

President Carter met yesterday with Archbishop Chrysostomos of Cyprus to discuss the dispute over the island nation.

According to one participant at the meeting, the Archbishop told Carter of "the disappointment of the people of Cyprus that nothing has happened" in the five years since Turkey invaded Cyprus.

The source said Carter promised to do his best to see that Turkish troops are removed from the island. There was no immediate comment from the White House.