DEMO - 1956 Ford Car Shop Manual - FordManuals.com

18 Chapter 1 General Engine Overhaul, Inspection, and RepairRunout,GaugeVn"MINIMUMMAXIMUM VALVEFACE RUNOUT0.002REFER TO SPECIFICATIONSFOR CORRECT DIAMETERZ LCHECK FOR BENT STEMFig. 17Critical Valve Tolerances Typical6480Tool-for Removing andInstalling Pilot6603Fig. 15Valve Seat Runout Check Typicalprecision valve grinder. Follow the instructions of theequipment manufacturer. Grind off onlyenough stockto remove pits and grooves. If the edge of the valvehead is less than y32 inch thick after grinding, replacethe valve. If the runout still exceeds specifications aftergrinding, check the equipment used in the grindingoperation.Grind all grooves or score marks from the end of thevalve stem. Do not remove more than 0.010 inch fromthe stem.The critical tolerances of the valve are illustrated infig. 17.(b) Refacing Valve Seats. Grind the valve seat(fig. 18) to a true 45 angle. Remove only enough stockto clean up pits or grooves. If the valve seat widthexceeds specifications, remove just enough stock fromthe top and/or bottom edge of the seat to reduce theAfter refacing valves and seats, it is good practice tolightly lap in the valves with a medium grade lappingcompound to match the seats.(c)Select Fitting Valves. Oversize valves with astem diameter of 0.003, 0.015, and 0.030 inch are available. Occasionally the 0.003 inch oversize valve is usedin production in one or more positions.If the valve to guide stem clearance is excessive andthe diameter of the valve stem is on the lower limit (asdetermined by measuring the valve stem with a micrometer), select a new valve with a stem diameter on theupper limit. If in the use of standard valves the clearance cannot be reduced to a satisfactory limit, reamthe valve guide (fig. 20) for the next oversize valvestem.d. Valve Lash Adjustment.Reference is made in the procedures for a preliminary(cold)valve lash adjustment to placing number 1piston ontop dead center(T.D.C.)at the end of thecompression stroke. Number 1 piston is on T.D.C. atwidth to specifications. Use a 30 angle wheel to remove stock from the bottom of the seat and a 60 anglewheel to remove stock from the top (fig. 19). Keepthe seat as near to the center of the valve face aspossible. Place Prussian Blue on the valve seat andinstall the valve to check the point of contact.Seat Width Scale30ANGLE WHEELFOR BOTTOM OF SEAT60ANGLE WHEELFOR TOP OF SEAT66046605Fig.16Measuring Valve Seat Width TypicalFig. 18Refacing Valve Seat Typical