The truth of this may never be known. I believe that the expert view is to drive off straight away, but to prove the science would take too long and not be wide enough in scope. By the time I've shuffled out of the garage and closed the door, then backed up the drive things are warming up nicely anyway.
My Metro Turbo had a terrible flatspot when cold (manual choke), so I always warmed it up for five minutes before driving off, but at fast idle, not tickover, with no ill effects.
The Coventry Climax portable firepump engines were designed to be started from cold and survive at maximum revs from cold, but had generous clearances in the bores, and used oil.
Last edited by DaveW; 27/11/13 05:26 PM.
