Re: Running In???
Without exception the most enduring minor topic of discussion centres on whether the manufacturers are kidding us about running-in....should we not just thrash them from new?...modern engines have tighter tolerances, so they don't need the same nursing as engines of old' and so on, and on, and on.
The 'thrash 'em' brigade always cite the competition guys who claim to 'beat them out of the crate' and the others claim to have little mechanical knowledge and so stick with the handbook instructions - light throttle, don't go above 4000 rpm and don't let the engine slog...oh and keep to this for the first 1000- 2000 miles.
The reason why we run engines in is to smooth the microscopic peaks left by the machining, honing or grinding operations on bearing/mating surfaces between pistons/rings and bores, between journals and shells and between shafts and bushes. Some of these bearing surfaces are subject to varying loads and extremes of temperature (crankshaft journals, pistons/bores and gearbox bearings) and others are under constant loading for a given engine speed (camshaft,valvegear, oilpump etc). However all rely on a film of lubricating oil to keep the surfaces from actually touching and to conduct away heat created by shear loads at the interface (piston to cylinder bore running can be patchy in this regard)
The peaks need to be removed without creating so much extra heat through friction that the materials melt and either tear the bearing surfaces or fuse with the opposing surfaces (seisure or pick-up). This is done over a given period at lower engine speeds and under light loadings. The result is a series of bearing surfaces which will support the lubricant uniformly and therefore carry greater loads for longer before failure, and in the case of the pistons/rings/bores, seal effectively and minimise friction....
Just passing through.......