The Ligier JS29 was a Formula One car designed by Michel Tétu and Michel Beaujon for the Ligier team for use in the 1987 season. It was originally developed for use with an Alfa Romeo turbo power plant but prior to the start of the season, Ligier lost the use of the engine. The car had to be re-designed around a Megatron Straight 4 turbo engine. Redesignated the JS29B, it scored a single point during the season when driver Rene Arnoux finished 6th in the Belgian Grand Prix. Later in the season, the car was further refined to a JS29C specification.

The JS29 was originally to be powered by a brand new turbocharged Alfa-Romeo 415T 4-cylinder engine. However, during pre-season testing lead driver René Arnoux publicly gave his thoughts on the engine, comparing it to used food which gave Alfa's parent company Fiat the excuse they had been looking for to pull the plug on the project. It was reported at the time that Fiat did not want Alfa Romeo involved in Formula One as a competitor to Ferrari who at that stage they also part-owned.

As a result of losing their engine supply so close to the start of the season, Ligier had to come up with an engine in order to compete. The team managed to get a supply of Megatron Straight 4 turbo engines for the season (the Megatron engine was the old BMW M12 engine formerly used by such teams as Brabham. They had been acquired from BMW by Arrows major sponsor, American insurance company USF&G, and were re-branded Megatron for 1987 and 1988). The updated car with the Megatron engine was now designated the JS29B. Arnoux was retained for the season and he was joined by Italian veteran Piercarlo Ghinzani.

...
Wikipedia