Dartin for Divorce
The sheet metal, or "wood" screws you are trying to use are expanding the hole and basically exploding the metal around them. The screws supplied with the valve covers, when new, often look almost like a tap. The first few threads are tapered (and often split), so that they actually cut threads into the metal. These are called "thread forming (or cutting) screws for soft metal". The hole size is real important... too small or too big, and they don't work. I've also seen little solid rivets with a real fast thread on them, that you hammer in. Sometimes they crack the mounting bosses too. Sorry to say I don't know what size thread forming/cutting screw you need, but a place like McMaster-Carr has every diameter and length that's made if you can't find them locally.
The sheet metal, or "wood" screws you are trying to use are expanding the hole and basically exploding the metal around them. The screws supplied with the valve covers, when new, often look almost like a tap. The first few threads are tapered (and often split), so that they actually cut threads into the metal. These are called "thread forming (or cutting) screws for soft metal". The hole size is real important... too small or too big, and they don't work. I've also seen little solid rivets with a real fast thread on them, that you hammer in. Sometimes they crack the mounting bosses too. Sorry to say I don't know what size thread forming/cutting screw you need, but a place like McMaster-Carr has every diameter and length that's made if you can't find them locally.