A method is provided for machining the fire deck of an engine block. The method includes providing a grinding wheel having an outer annular grinding element disposed concentrically or the wheel may be provided with an inner annular grinding element disposed concentrically inward of an outer element. The outer element comprises a single layer of relatively coarse diamond abrasive brazed on a metallic substrate, while the inner element comprises a single layer of relatively fine diamond abrasive brazed on a similar substrate. The outer grinding element and the inner element if utilized, is formed as a discrete unit individually fastened to a backing plate to facilitate independent height adjustment of the elements relative the backing plate. The method further comprises orienting the grinding wheel with its axis of rotation at a predetermined oblique angle a relative the fire deck. The wheel is then translated towards the engine block along a tool path parallel to the fire deck wherein the outer ring will engage the block for bulk material removal, followed by the inner ring, if utilized, which removes a smaller amount of material to apply the requisite surface finish to the fire deck.