An investor group led by a New...

An investor group led by a New York-based investment banking firm said it is offering $695 million to buy Quaker State Corp., the motor oil refining company. Ardshiel Inc. said it is offering $26.50 a share for the Oil City, Pa.-based company, which refines and sells Quaker State motor oil, owns Quaker State Minit-Lube Inc. drive-in automobile lubrication centers, and manufactures truck lighting systems and automobile brake lights. Ardshiel said it currently owns about a 3.3% interest in the company. It did not disclose the identities of other investors. Quaker State spokesman Ben Faulkner said the company had no comment on the offer.