This year, drivers are limited to using just 8 engines for the entire world championship.
It has emerged in recent days, however, that the FOTA group of carmakers wanted to step up the measure so that only 5 engines per driver may be used in 2010.
According to speculation, the manufacturers Ferrari, Renault, Toyota, BMW and Mercedes wanted the change so that selling customer engine packages for the low price of 5m euros was more cost effective.
However, Cosworth – the only independent engine maker – was apparently less keen on the move to 5 engines.
It is believed Cosworth was concerned about the reliability of its four-year old design, last supplied to Williams in 2006, if subjected to the harsher long-life engine rules.
"We are making a business of doing eight engines per car for a price of five million," Cosworth CEO Tim Routsis is quoted as saying by Germany's Auto Motor und Sport.
"The manufacturers should also be able to do it," he added.
A row between Max Mosley and FOTA over whether Cosworth should be allowed to run without a rev limit next year played a role in the sport's recent political crisis.
Ultimately, FOTA won and Cosworth's customers Manor, USF1 and Campos will all be subject to the 18,000 limit. But Routsis insists the 2010 retune will not result in the engine being uncompetitive.
"Our simulations show that the retuned (Cosworth) version will be competitive," he said. "If it was in one of the winning cars this year, the results would not have been different."
Routsis said the first 2010-spec Cosworth engine will be delivered in November.