The SUNRED Engineering SEAT Leons of Tiago Monteiro and Andrea Barlesi will switch to turbocharged petrol engines of the team's own preparation for this weekend's World Touring Car Championship round at Valencia.
Both Monteiro and Barlesi used 2-litre TDI units at the Monza season opener, and are still planning to switch to the new 2012-spec 1600cc powerplants developed and homologated by SEAT Sport at a later point in the season.
Currently though, a shortage of parts for the new engines means that there are not enough complete units to go around. Only the SEAT-backed cars of Gabriele Tarquini and Aleksei Dudukalo, Pepe Oriola's SUNRED machine and Darryl O'Young's Special Tuning Racing Leon will run the latest engines at Valencia.
Because Monteiro, Barlesi and Fernando Monje - who is making his WTCC debut with the team this weekend - are all switching units mid-season, each will be penalised with 20kg of ballast this weekend, bringing the total weight of each car to 1170kg.
SUNRED boss Joan Orus confirmed his desire to utilise SEAT Sport's 2012-spec, Skoda-derived engine later in the season.
"We decided after Monza that it would be better for us to return to the homologation that we have used last year, with the nationally homologated, SUNRED developed engine," he told AUTOSPORT. "For sure, we would have liked to go with the newly homologated SEAT Sport engine, but those units are not ready because they still need to produce more parts.
"But we have all the parts that we need for the 2011 engine; they are all in stock and on the shelf! I can put it in without any problem. I think we will race this engine until the halfway point of the season. Maybe when we go to America and Asia we will be able to change to the SEAT Sport engine. The only change to the cars this weekend is on the engine, everything else is the same.
"To clarify, our engine is completely designed by SUNRED, and all development is by SUNRED. SEAT Sport is using an engine from the group, sourced from, Skoda."
Despite incurring the ballast penalty, Orus was optimistic the revisions would produce a step forward.
"We really think our homologation is better than the diesel engine that we used in Monza, so we decided to change," he said. "I hope we can achieve some very good results with this 1.6T engine. We will do our best."
The decision leaves Special Tuning Racing's Tom Boardman as the sole SEAT 2.0 TDI competitor at Valencia. Boardman was forced to sit out the opening meeting in Italy owing to a shortage of SEAT Sport engine parts.