Some rejected teams say new entrants aiming to enter Formula One next year were told they had to use Cosworth engines to secure a place.
They have privately questioned last month's selection procedure, with one expressing his view in a letter to a senior figure at an existing Formula One team.
Just before entering a meeting with the governing International Automobile Federation in London on June 11 he says he was told if his application to have any chance of success, he would need to report Cosworth as his engine supplier.
He says he had a real possibility of obtaining a Renault, Mercedes or Ferrari engine but it was made clear the "powers that be" wanted Cosworth.
The three new teams selected - Campos Meta, U.S. F1 and Manor Grand Prix -- have all agreed three-year deals to use Cosworth engines.
Others, such as Kuwaiti-financed Prodrive and chassis maker Lola, were rejected.
Cosworth supply none of the current 10 teams but have an impressive pedigree in the sport going back decades.
There is no suggestion Cosworth asked the governing body to favour them or sought any unfair commercial advantage.
