Tenneco Inc., a diversified industrial manufacturer and petroleum producer, reported record second-quarter earnings of $118.3 million ($1.09 a share) Tuesday from improved performances in five of its eight major businesses.

The gain represented an 11 percent increase from earnings of $106.5 million ($1.03) last year. Revenues in the three-month period totaled $2.2 billion compared with $1.9 billion a year ago.

Tenneco Chairman James Ketelsen attributed part of the record figure to a greater contribution to earnings from Philadelphia Life Insurance Co., which became a wholly owned Tenneco subsidiary March 1.

He said integrated gains came from oil operations, natural gas pipelines, construction equipment and farm machinery, chemicals and automotive parts.

For the first six months of the year. Tenneco reported net income of $228.4 million ($2.13) compared with $211.7 million ($2.05) last year. Revenue increased from $3.7 billion to $4.2 billion.

LTV Corp., a steel producer and aerospace concern, reported sharply higher profits for its second quarter compared with the same period a year ago.

The company said yesterday its profit from operations surged to $33.4 million ($2.24 a share) from $1.6 million (7 cents). Revenues came to $1.33 billion compared with $1.21 billion.

Chairman Paul Thaver said "the strong operating performance in the second quarter of 1978 was primarily the result of a significant improvement in LTV's steel unit, coupled with continued strength in earnings from aerospace operations."

Six-month net income rose to $8.4 million (49 cents) from a $2 million loss during the 1977 first half. Sales inccreased to $2.6 billion from $2.3 billion a year ago.