On my 638 14 big chief I have #2 cylinder getting oil on the plug. It still have 190 cranking compression but I haven't did a leak down yet. My question is can I block off the second stage to that cylinder to minimize detonation.
A lot of things can cause oil to get into a cylinder, bad valve guide, leaking intake gasket, leaking threads, pinched rings, lifted ring land, cylinder wall damage, collapsed piston shift....etc
If you have the time, it's best to check it out before major damage occurs, if you are looking to make the next round and really don't care if you hurt it worse or not, by all means, put some blanks in that hole and let it eat. but don't forget, If you plug one nozzle, the other 7 will see a little higher pressure at the jet and thus flow a little more, its an easy way to hurt another one.