What exactly happened to Tänak’s broken engine?

Ott Tänak started last weekend's Rally Estonia with a five-minute penalty after an engine change


The process of stripping the engine which cost Ott Tänak and M-Sport the chance of winning last week’s Rally Estonia is underway back at the team’s British headquarters.

Ahead of the Tartu-based event, the Estonian’s Ford Puma Rally1 Hybrid had been fitted with its second of the two engines permitted for each season. The car had gone through its usual pre-event running, with the brand-new engine built to the same specification as its predecessor.

It was only after scrutineering had taken place and the engine sealed that a misfire was detected on the car.

M-Sport technical director Chris Williams has talked DirtFish through timeline which led to the five-minute penalty.


“Everything was done in the same way,” he said. “We have a process which involves running on the dyno for an hour then in the car probably around 40 kilometers, including the shakedown process back in the UK.

“The data from the shakedown looked good, we had no problems, power curves were OK from dyno. We’d done all the usual due diligence and the car was signed off – we’d done everything we do to make sure this sort of thing doesn’t happen.

“We came out to Estonia and the first thing was the car was scrutineered. That was about nine o’clock on Wednesday morning. Everything was fine. Around lunchtime the car had to go to the scales to be weighed. When the boys came back in they said: “It’s got a misfire, we think. It just sounds a little bit off, on idle.”

“OK. We brought it back and started changing some bits and it didn’t make any difference. We were looking at each other and asking: “Are we worried?” There was still nothing on the data. We kept looking. We took the turbo off, we replaced the wiring loom, the spark plugs, the injectors, coils. We changed everything we could except for the hardware.

“We knew immediately after the first run of shakedown that there was something seriously wrong [on Thursday].”


Immediately it became clear the engine wasn’t going to last, so the call was made to change the engine. A change of engine that is permitted between scrutineering and the start of the rally but that brings an immediate five-minute penalty.

This chassis will run with that engine for the rest of the year.

Asked to speculate on what the problem might have been, Williams is almost sure it’s an issue from the build process.

“It was a brand-new engine,” Williams said. “Obviously we don’t know until we look into the engine and find out more, but it looks like there’s something gone wrong with the new build. We didn’t do anything different, we used the same parts and the same process.

“Like I said, we have good, quality procedures in place that would pick issues up. Something has gone wrong.”

After starting with his five-minute penalty, Tänak finished his home round of the championship in eighth place.