Westinghouse Electric Corp. earnings increased 16.9 percent in the second quarter of 1978 over the comparable period a year ago, Chairman Robert E. Kirby reported yesterday.

Net income in the three months ended June 30 amounted to $74.81 million, or 86 cents a share, compared with $64.02 million, or 73 cents a share, in the same period of 1977.

Sales in this year's second quarter were $1.68 billion, up 9.4 percent over $1.53 billion in the 1977 quarter.

In the first six months of 1978, Westinghouse's net income was $141.05 million, or $1.62 a share, compared with $117.22 million, or $1.34 a share, last year.

After reclassifying the settlement of a uranium-contract lawsuit as an extraordinary loss, the six-month 1977 earnings before that item were $121 million, or $1.39 a share.

Sales in the first half of 1978 totaled $3.22 billion, compared with $2.96 billion in the same period last year.

Kaiser Aluminum & Chemical Corp. yesterday reported second quarter 1978 net earnings of $52.8 million or $2.61 a common share, a record for any quarter and well above the previous high of $40.3 million or $2.01 a share earned in the second quarter last year.

A gain of $2.7 million or $.14 a share due to the translation of long-term foreign currency exposures is included in results for the 1978 quarter, and compares with a loss of $1 million or $.05 a share in the same period last year.

Sales for the second quarter totaled $678.8 million, compared with sales of $634.2 million in the 1977 quarter.

for the first half of 1978, the corporation's earnings were $77.3 million or $3.81 a share, compared with earnings of $64.2 million or $3.19 a share earned in the first six months of 1977.

The translation of long-term foreign currency exposures resulted in a loss of $3.4 million or $.17 a share in the first half, compared with a loss of $.5 million or $.02 a share in the same period last year.

First half sales totaled $1,277.0 million, up from sales of $1,156.8 million in the first half of 1977.

The company's return on average invested capital in the first half of 1978, on an annualized basis, was 10.2 percent.

Teleyne Inc. said yesterday that net income for the second quarter ended Junde 30 was $65.8 million, compared to $27.6 million in the same period last year.

Earnings per share were $5.04 compared to $2.09 in the second quarter of last year, the diversified company said, while sales were $621.4 million versus $524.6 million.

Teleyne has interests in industrial products, aviation and electronics, specialty metals, consumer products and insurance and finance.

Teledyne credited the huge earnings gain primarily to improved operations by its Argonaut Insurance Co. subsidiary. Argonaut experienced large losses on reinsurance business in last year's second quarter, a company spokesman said, but is now operating profitably.

Results at another subsidiary, United Insurance Co. of America, also ran well ahead of last year's second quarter, Teledyne said.

Walt Disney Productions yesterday reported record revenues and net income for the third quarter and nine months ended June 30.

Net income for the quarter was $47.2 million, up 17 percent from $38.9 million in the same period a year ago, Disney said. Earnings per share were 76 cents, a 21 percent increase from the 63 cents reported last year.

Net income for the nine-month period was $60.9 million compared to $49.9 million last year, Disney said, while earnings per share were $1.88 versus $1.54.

Allied Chemical Corp., which has interests in energy, fibers and fabricated products and chemicals, yesterday reported a substantial decline in net earnings for the second quarter.

Net earnings for the three months ended June 30 were $35.9 million, or $1.27 a share, down from $62.5 million, or $2.23 a share last year, the company said.

An Allied Chemical spokeswoman said the earnings figure for last year included a non-recurring after tax gain of $19 million from the sales of its dye business and a coke plant.

For the quarter, sales gained 26 percent to $813.2 million from $785.5 million last year.

For the first half of the year, net earnings totaled $65.8 million or $2.33 a share, a drop from $76.1 million or $2.72 a share for the same period a year ago. Sales for the first half amounted to $1.59 billion, up from $1.47 billion last year, the company said.

The Rochester-based Gannett Co. Inc. reported a net earning increase of 20 percent for the second quarter. It marked the 43rd consecutive quarter of increased comparative earnings.

The firm also reported a 21 percent net earnings gain for the first half of 1978, aided in large part by an 8.2 percent gain in advertising lineage.

The newspaper group said net income for the second quarter was $22.53 million compared with $18.73 million in 1977. For the first half, net income was $37.7 million compared with $31.2 million.

Gannett publishes 77 daily newspapers in 20 states and two U.S. territorites. The company recently announced an agreement in principle to merge with combined Communications Corp. of Phoenix, a diversified media company.

PPG Industries Inc., one of the nation's largest producers of glass for the construction and automotive industries, yesterday reported first half and second quarter sales and earnings.

Second quarter earnings amounted to $50.3 million, or $1.60 a share, on sales of $706 million, compared with a profit of $43 million, or $1.38 a share, on revenue of $640 million a year ago.

PPG's previous high earnings mark was in the second quarter of 1977. Sales reached a quarterly peak in the first quarter this year at $648 million.

Year-to-date earnings amounted to $85.9 million, or $2.74 a share, on sales of $1.35 billion, compared with a profit of $78.2 million, or $2.51 per share, on revenues of $1.22 billion a year ago.

Colgate-Palmolive reported a 6 percent gain from a year ago in second quarter profit to $47.7 million or 60 cents a share from $45.21 million or 56 cents a share.

Sales rose to $1.046 billion from $956 million.

First half net was $83 million or $1.04 a share on sales of $2.066 billion against $77.88 million or 97 cents a share a year ago when first half sales were $1.889 billion.

Chairman David Foster said sales grew faster than earnings because of heavy expenditures on new product introductions and higher interest expense.