The MSR team that had been the class of the field suffered technical drama shortly after the midway point of the race, with the engine cover of the #60 Acura ARX-06 having to be taken off during a FCY due to a suspected gearbox leak.
This dropped Simon Pagenaud down to third when the race went back to green, but the 2016 IndyCar champion made quick work of Pipo Derani in the #31 Action Express Racing Cadillac to move back up to second position.
Pagenaud then began to reel in new race leader Dane Cameron and after running side-by-side with the Porsche driver over the banking, he made the move stick into Turn 1 to retake the lead of the race.
Helio Castroneves took over driving duties from Pagenaud in the 14th hour and set about extending his advantage up front, building a buffer of nearly 40 seconds over the #02 Chip Ganassi Cadillac of Alex Lynn, now in second place after demoting the #6 Porsche of Cameron.
But Castroneves’ good work was undone by a full-course yellow in the 15th hour, deployed when the #64 TF Sport Aston Martin Vantage GT3 stopped on track and became the latest retirement of the race.
Castroneves had to pit twice during the intervention, ostensibly to top up oil, and dropped to sixth and last among the GTP entrants on the lead lap of the race.
Porsche was the biggest beneficiary of MSR’s troubles, with Nick Tandy propelling the #6 963 to the lead at the start of the 15th hour after electing not to make a pitstop.
On old tyres, Tandy did come under pressure from Sebastien Bourdais in the #01 Ganassi Cadillac, but managed to hold on to the lead of the race until the end of the hour.
Lynn made it two cars from CGR Cadillac team inside the top three, while Pipo Derani was running fourth in the similar V-LMDh run by Action Express Racing team until he began to slow down with a gearbox issue.
This promoted the MSR Acura into fourth, with Castroneves having passed the #24 BMW of Philipp Eng after the restart as he continued his recovery drive.
Acura’s troubles were compounded by the Wayne Taylor Racing team having to bring its #10 ARX-06 behind the wall moments after MSR first ran into technical issues after the midway point of the race.
Another unscheduled pitstop during the same full-course yellow period dropped the team three laps down, although it has managed to gain one lap back since then, with Filipe Albuquerque currently at the wheel of the Oreca LMP2-based contender in seventh.
The LMP2 class featured a thrilling battle between Nicklas Nielsen in the #88 AF Corse and Paul Loup-Chatin in the similar #52 PR1/Mathiasen Oreca 07, but it was Ben Hanley in the #04 APR entry that held the lead after 15 hours of racing at Daytona International Speedway.
Josh Pierson sat second in the #35 TDS Racing Oreca, with Matthieu Vaxiviere third in the AF Corse entry after taking over the driving duties from Nielsen.
The LMP3 field was led by Nico Varrone in the #17 AWA Duqueine, six seconds ahead of Nico Pino in the #33 Sean Creech Motorsports Ligier.
In GTD Pro, factory Mercedes driver Dani Juncadella moved the #79 WeatherTech AMG-GT3 into the lead after leapfrogging the #23 Heart of Racing Aston Martin then driven by David Pittard during a pitstop cycle in the 14th hour.
Jack Hawksworth sat second in the #14 Vasser Sullivan Lexus RC F GT3, while Corvette rebounded from earlier issues to move to third in class with Tommy Milner at the wheel of the #3 C8.R.
Roman de Angelis passed the #57 Winward Mercedes of Philipp Ellis after a tight scrap to put the #27 Heart of Racing Aston Martin Vantage GT3 into the GTD lead, with Mike Skeen running third in the Team Korthoff Motorsports AMG GT3.
