UPDATE 1-Valero moves back Port Arthur overhaul -- sources

* Work delayed in part due to crane arrival

* Second overhaul rescheduled by Valero (Adds details on units to be shut down; length of shutdown)

HOUSTON Jan 18 (Reuters) - Valero Energy Corp (VLO.N) has moved back the start of a planned vacuum distillation unit and coking unit overhaul at its 287,000 barrel-per-day (bpd) Port Arthur, Texas, refinery, according to sources familiar with refinery operations.

A Valero spokesman declined to discuss the refinery's plans and said the company will update its turnaround schedule on Jan. 26 during an earnings conference call.

The overhaul was due to begin in early January, but has been delayed in part by the late arrival of a giant crane needed to lift out coking unit drums during the overhaul, according to the sources. The crane is expected to be ready in early February, which is the earliest the work could begin.

Valero has moved back the start of an overhaul at its 170,000 bpd McKee refinery in Sunray, Texas, from March to April.

The vacuum distillation unit, which is the larger of two that do the initial refining of crude oil at the refinery, will be shut along with the coking unit, sulfur recovery units and the gulfing unit, a hydrogen desulfurization unit.

The Port Arthur work is expected to run 55 days.

The gasoline-producing fluidic catalytic cracking unit at the refinery will remain in operation during the overhaul. (Reporting by Erwin Seba; editing by Andre Grenon)