Updated

Dale Earnhardt Jr. will have to start from the rear of the field in Thursday's first qualifying race for the Daytona 500 due to an engine change.

During Wednesday's practice at Daytona International Speedway, Earnhardt Jr. blew a motor in his No. 88 Hendrick Motorsports Chevrolet. He suffered engine failure halfway through the first of the two practice sessions for the Budweiser Duel (twin-qualifiers). He completed just 11 laps around the 2.5- mile speedway, with his best lap clocked at 191.579 mph.

"We just broke a motor, simple as that," Earnhardt Jr. said. "(The team) will figure out what happened. I'm sure there's some logical explanation for what happened. They'll just put a new (engine) in, and we'll start at the back of the qualifier tomorrow. We'll just try to race up through there."

Earnhardt Jr. finished 11th in last Sunday's time trials for the Daytona 500. It had earned him the sixth starting position for race one in the twin qualifiers.

Early in the first practice session, Carl Edwards and Ryan Newman made contact while running in a five-car draft. Edwards hit the left-rear of Newman's car and spun him around.

"It was unfortunate, but that's why we have practice," Newman said. "I guess my car just got light in the back going into (turn) four."

Newman sustained cosmetic damage to the left side of his No. 39 Stewart-Haas Racing Chevrolet. His team was able to make repairs to the car. Edwards did not suffer any damage to his No. 99 Roush Fenway Racing Ford.

"I was underneath Ryan, and I was going to side draft him a little bit, but all of the sudden, his car just turned sideways," Edwards said. "I don't know if it was a function of the 18 car (Kyle Busch), which was a little bit behind him. This to me is something new with these cars."

This year's Speedweeks at Daytona has marked the competition debut of NASCAR's new Generation-6 race car in the Sprint Cup Series. There has been at least one multi-car crash in each of the Sprint Cup practice sessions since Speedweeks activities began last Friday. Edwards was one of five drivers involved in a crash during practice for the Sprint Unlimited preseason race at Daytona. The event here last Saturday featured a nine-car accident as well.