Originally posted by Motorman
on the NS 12's break it in and hammer down, takes about a gallon before they really loosen up though.
Today I've been ending the break-in of mine RR12 and.... whew! love it. Doing the break-in of the engine is a bitch (the piston is tough to beat), needed almost 2 litres of fuel but at the end of the afternoon hammered it and was simply incredible.
Everything changed it (gearing, shifting points, clutch spring) but love how the engine pulls and launches the car from the hairpins and from still.
P.S: To all with one NSR or RR12, don't change the 'small' (9 fins) cooling head by the big (11 fins). Those engines with the new piston needs and holds much better higher temperatures, those engines are happy at 145 - 150ºC.