Luca Marmorini has lashed out at Ferrari after being ousted as the fabled team's engine boss.
Also well-known for his position at Toyota, the Italian's F1 career dates back more than two decades to Maranello.
But he was ousted by new team boss Marco Mattiacci a few weeks ago, amid the general feeling that he was to blame for Ferrari's underpowered turbo V6 'power unit'.
Marmorini told Italian F1 insider Leo Turrini that he had no intention of getting involved in any "needless controversy" in the wake of his departure.
"Unfortunately there are people in Maranello who should be silent who like to blame," he said. "So I open my mouth in response to a series of provocations."
Ferrari runs the risk of damaging the bedrock on which the many past successes were built.
Marmorini hit out the hardest against the notion that "all the woes of the F14 T are the fault of the power unit.
"As if a company with the history of Ferrari has forgotten how to make engines!
"I mean, I accept any criticism, but do not tell me that there are people at Maranello who do not know the business of turbos, hybrids.
"Let's set the record straight - with my colleagues I made a smaller size (engine) than Mercedes and Renault because that is what Mr (Nikolas) Tombazis, the project manager of the car, asked for.
"He said he wanted a very compact PU, with small radiators, because the reduced power would be compensated by aerodynamic solutions that give us an advantage over the Mercedes and Renault cars.
"It was exactly like that, except that when we found the competition, we had less power but the compensation from the aerodynamics was not there."
Marmorini said he was dismissed by Mattiacci, even though "in three months we saw each other twice - first for a greeting, the second when he gave me a letter that confirmed my departure from the company".
"Look, I don't want to accuse anyone," he added. "Really. But Ferrari is entrusting its racing department to inexperienced people who are putting blind faith in certain people who so far have shown nothing."
Marmorini said he is referring to Britons Pat Fry and James Allison.
"Ferrari also runs the risk of damaging the bedrock on which the many past successes were built," he added. "I don't speak for me as I'm already gone.
"But I'm sorry for the good engineers who are still there and demoralised."
Marmorini also responded to reports his future lies at Renault, another marque that has struggled at the start of F1's all-new 'power unit' era.
"It's not true that I have signed already with Renault," he insisted.
"Indeed, at the moment in a Formula One that imposes an engine freeze, I like it very little. But I'm honest - Grands Prix have their charm and maybe in a month I will change my mind," said Marmorini.