These days an impact wrench can save the bother of locking the crankshaft, gearbox or whatever is being worked on.
Traditional method of locking an engine is to remove the starter motor and lock the flywheel ring gear with a suitable lever, though sometimes a certain amount of ingenuity is needed to get the job done and it is well worth having an armoury of strap and/or chain wrenches to grip a pulley, various blocks of wood for jamming in the crankshaft after removing the oil pan or on top of the piston after removing the cylinder head and temporarily refitting it.
Filling the cylinder with grease or heavy oil can provide enough hydraulic resistance to release a bolt (if the valves are closed).
Beware of left hand threaded nuts and bolts and also fixings that have had adhesive applied; in the latter case warming the fixing before removal helps...
Answers & Comments
There should be two parallel flat spots for a wrench, adjacent to the clutch bolt/washer. 12" pump pliers will work.
These days an impact wrench can save the bother of locking the crankshaft, gearbox or whatever is being worked on.
Traditional method of locking an engine is to remove the starter motor and lock the flywheel ring gear with a suitable lever, though sometimes a certain amount of ingenuity is needed to get the job done and it is well worth having an armoury of strap and/or chain wrenches to grip a pulley, various blocks of wood for jamming in the crankshaft after removing the oil pan or on top of the piston after removing the cylinder head and temporarily refitting it.
Filling the cylinder with grease or heavy oil can provide enough hydraulic resistance to release a bolt (if the valves are closed).
Beware of left hand threaded nuts and bolts and also fixings that have had adhesive applied; in the latter case warming the fixing before removal helps...