valve seal repair question

[jick.cejoco]

being not familiar with your engine, i will make these assumptions:
1-that the engine has hemispherical combustion chamber- the spark plug are installed in the center of the combustion chambers;
2-that your engine is of "I" head design ( both valves in the cylinder head).
3-that it is of overhead camshaft design,
4-that the valves are operated directly of the camshaft without the need of rocker arms.
5-that the spark plugs are seated deep into the spark plug tubes and that the spark plugs have a 5/8 inch hex drive.
there are two ways to do the job without having to remove the cylinder head;
1- with a reliable adequate sized air compressor, you can (a) place the particular cylinder in top dead center on power stroke, (b) remove the spark plug, (c) with compressed air applying pressure to the combustion chamber( the compressed air will hold the valve in place by air pressure, e.g., if the air pressure is 120 psig and the valve is about 1 1/2 square inch- there will be approximately 180 pounds of force holding the valve up in place), (d) compress the valve spring to remove the valve keeper, (e) the valve seal is accessible for replacement, (f) reassemble in reverse order as the removal procedure.
2-without an air compressor, (a) remove spark plugs, (b) place the specific cylinder close to top dead center on compression stroke, (c) using a shoe lace like the ones used for combat boots, introduce into the combustion chamber through the spark plug hole leaving one end out for easy extraction, (d) adjust the length of volume of the shoelace just enough for the piston to attain top dead center, (e) compress the valve spring to free the valve keepers up leaving the valve stem seal accessible for replacement.

*don't forget to lubricate the stem seal. preferrably chrome-molybdenum-graphite engine assembly lubricant to prolong the life of your new valve stem seals.