* Overhaul delayed due to problems in building new coker
* Work was scheduled to begin in early Oct. (Adds BP no comment)
HOUSTON, Sept 27 (Reuters) - A planned overhaul of a 100,000barrel per day (bpd) crude distillation unit at BP Plc's 405,000 bpd Whiting, Indiana, refinery has been moved fromOctober to November, according to two sources familiar withoperations at the refinery.
Problems with construction of a coking unit as part of a$4-billion revamp of the refinery was the reason forrescheduling the overhaul, expected to last at least a month,said the sources who are not authorized to discuss the matterpublicly.
The sources also said the overhaul's start could be pushedback into 2014 depending on the progress to completeconstruction of new units at the refinery, which is due tofinish by the end of the 2013.
A BP spokesman declined on Friday to discuss the Whitingrefinery's maintenance plans.
The 102,000 bpd delayed coking unit is the last underconstruction at the refinery as part of a revamp to run cheapercrude from Canada's tar sands oil fields in Alberta.
"They keep finding all kinds of problems," said one of thesources about the construction project.
BP repeatedly rescheduled the start-up of a rebuilt 260,000bpd crude distillation unit to ensure it's initial operationwould be successful. That unit began operation in July.
Work on the 100,000 bpd Pipestill 11A was scheduled tobegin in early October and expected to last four to six weeks,the sources said.
A crude distillation unit or pipestill does the initialrefining of crude oil coming into a refinery and providesfeedstocks for all other units. (Reporting by Erwin Seba; Editing by Gerald E. McCormick)