CHARLOTTE, N.C. -- Toyota Racing Development will introduce upgraded engine parts and make adjustments in power for Sunday's Sprint Cup race at Pocono Raceway to ensure durability moving forward.
TRD had engine failures in the cars of contending drivers Matt Kenseth and Martin Truex Jr. last weekend at Dover International Speedway. That brought their total for the season to six, two more than the Ford engines and four more than the Chevrolet engines.
TRD senior vice president David Wilson told ESPN.com on Tuesday that four of the failures -- including both at Dover and one the previous week at Charlotte -- were related to the valve train.
"We probably pushed a little too hard and we need to put margin back into our engines," Wilson said by phone from TRD headquarters in Costa Mesa, Calif. "What we're doing and focusing on is durability. I have the entire group at TRD putting performance stuff on the backburner and focusing on nothing but durability."
Wilson is working closely with the three-car teams of Joe Gibbs Racing and Michael Waltrip Racing, the only organizations TRD supplies engines to, to make sure they understand what is happening. He also plans to talk to drivers from those teams to "give them peace of mind that we're doing something."
Wilson insisted this is not a time for panic, noting a year ago that TRD was in line with other top engine builders when it came to failures in races and practice. By his count TRD had 10, Hendrick Motorsports 13, Earnhardt Childress Engines 10 and Roush Yates Engines 11.
"Certainly, six engine failures across the first 13 races is completely unacceptable," Wilson said. "My expectation is we will get this under control. We may have to take half a step back, but clearly we've demonstrated we have plenty of speed and we can probably afford to take a step back."
TRD engines have won five of the 13 races and taken the pole eight times, including the top four spots at Dover. Five of its drivers -- Clint Bowyer (third), Kenseth (fifth), Kyle Busch (ninth), Truex (15th) and Denny Hamlin (26th despite missing four races) -- are Chase contenders.
Wilson doesn't expect the slight reduction in performance to impact those results.
"When we have issues like this it does become a distraction," he said. "That's not a good thing. Guys should be able to have confidence in their equipment. We don't want them to drive any differently than they know how to drive. We don't want them having to baby their engines."
Busch has been the most outspoken about engine failures over the past few years. He's had two this season, the latest two weeks ago at Charlotte that ended a dominant performance.
"We should never put any of our drivers in a position where they have to speak to this," Wilson said. "I certainly acknowledge Kyle is ultra competitive and he hates to lose more than any driver I've ever worked with."
There have been 17 Toyota engine failures this season, but eight of those were built by Triad Racing Technologies, two by Racing Engines Plus and one by Pro Engineering that supply engines to lower-tier Toyota teams. Wilson said while TRD does supply unfinished engine blocks and heads to those builders, that's as far as the relationship goes.
"We have zero control, zero responsibility for those engines," he said. "There is no correlation between our issues and their issues. They may as well be Chevys and Fords. Other than having the same blocks and heads, that's as far as that goes."
Wilson said the valve train issues TRD has had are not unique to problems other engine builders have with other manufacturers. He said the steel springs that NASCAR stipulates teams must use are put through tremendous pressure, particularly on newly surfaced tracks where drivers have more car control and get on the throttle coming out of corners faster.
The next two races, at Pocono and Michigan, are on tracks that have been resurfaced over the past couple of years, so the upgraded parts come at a good time. Wilson said TRD is testing the engines on the Pocono configuration to give information to teams so they know in which direction they're headed.
"We understand with the way the points are distributed that DNFs hurt just as much as a win helps," Wilson said. "We've got to make sure our guys are able to finish the race."