Heat grill to high. In an 11-quart stockpot, combine the potatoes, chorizo, onion, beer, bay leaves, 1 teaspoon salt, and ½ teaspoon pepper.
Add just enough water to cover potatoes. Add the corn, shrimp, and clams in layers. Cover the pot.
Cook on grill until clams open, shrimp are opaque, and potatoes are tender, 20 to 25 minutes. (Or cook on the stove over medium-high heat.)
Transfer to a large platter and serve with the bread and butter.