Show VALVE STEMS AND THEIR EXPANSION An ob obscure curc engine difficulty sometimes sometimes some some- times occurs that Is manifested b by a reduction of or compression when the cylinders cylinders ders are hot although h they may b bo he known to be tight when the parts arc are cold This Is caused b by the expansion of or orthe the valve stems during during- the warming n up process Unless a proper amount of clearance clearance clear clear- ance is flowed allowed between tho the ends of the th stems and the ho tappets this may be enough to prevent the valves val from seatIng seatIng seat- seat In Ing properly |