The Senate Finance Committee yesterday voted to grant a tax cut to oil refiners and preserve a tax advantage for home builders, two votes that critics on the panel labeled blows to the effort to overhaul the tax code.

But the committee stopped short of approving an amendment to its broad tax-revision bill that would have cost $5 billion in tax revenue over five years. Committee Chairman Bob Packwood (R-Ore.) warned that approval of the amendment, which aided manufacturers, would "break the spillway."

Instead, senators passed a compromise proposal that cost $1.9 billion. Altogether, yesterday's alterations in Packwood's tax-overhaul plan would cost $3 billion in revenue over five years, leaving the package about $14 billion in the hole. Unless taxes are raised elsewhere in the bill, the federal deficit thus would be increased by that amount over the five-year period.

"Today was a continued bleeding of the bill," said Sen. Bill Bradley (D-N.J.). "It makes lower rates for middle-income Americans a tougher thing to achieve."

Packwood, who opposed most of the amendments, said after the committee's session that he expects the panel eventually to approve "a good bill, and it will be revenue-neutral." He and Bradley both said several times during the day that they expect the Finance Committee to "revisit" some of the areas where special exceptions had been granted or where revenue had been lost.

The failed amendment for manufacturers, offered by Sen. Charles E. Grassley (R-Iowa), would have cut back on Packwood's proposals to tie the costs of producing a good more closely with the tax deductions that can be taken for those costs. For goods sold right away, the Packwood proposal would have little effect; for those that sit on the shelf, some deductions would have to be taken in later years than they are now.

Altogether, Packwood's proposals in the area of inventory would raise about $18 billion over five years. Grassley wanted to give back $5 billion of that in a way targeted more toward manufacturers than toward retailing and wholesaling firms. Last week, the committee voted to exempt small retailers and wholesalers from the inventory requirements.

"This is one of those subjects every committee member has been lobbied on," Packwood said in urging members to vote against the Grassley proposal. "If this one passes, we've broken the spillway, broken the dam."

It failed, 10 to 6, with 8 of the panel's 9 Democrats and 2 of its 11 Republicans voting against it. The committee then agreed by a 9-to-7 margin to adopt the Grassley amendment only for equipment and machinery that was in operation as of Sept. 25, 1985, at a revenue cost of $1.9 billion.

Earlier, the panel accepted an amendment proposed by Sen. David L. Boren (D-Okla.) to let owners of refineries write off their costs of construction or acquisition over five years, rather than the 10 years proposed by Packwood. The write-off period now is five years, but the effect of the Boren plan would be to permit more of those deductions to be taken in the early years of the period, an effective tax cut.

The change would cost $900 million over five years in relation to the Packwood proposal. Boren said it was necessary because refineries, like other segments of the oil industry, are in poor financial health.

Worrying that an industry's financial condition should not set a standard for how it is taxed, Packwood said, "I can see the inevitable process if we start to open it up now . . . most of us can point to some major industries in our state that are in trouble."

The Boren amendment passed, 10 to 5.

Senators on the Finance Committee also rejected an amendment to curtail a tax break for home builders, called "builder bonds." It lets them postpone the payment of most taxes if they borrow against mortgages they have offered. And the committee agreed to a proposal by Sen. Steve Symms (R-Idaho) to let farmers with irrigation equipment postpone payment of some taxes if that equipment is sold along with the farm.