Originally Posted by BundyMan

Not too sure about the OS engine, Nova engine is something like 4.29mm I think. If the crankpin is worn, your engine may keep eating plugs, like what I had recently. Try turning the flywheel and check the freeplay to TDC. What I normally do is apply some oil on the gap (where the conrod meets the crankpin and see "how much" bubble it creates.