An outer body for a rotary engine comprising: two axially spaced apart end walls; a peripheral wall extending between the end walls and defining an internal cavity therewith for receiving a rotor therein; an insert (34;134) received in the peripheral wall, the insert (34;134) having a pilot subchamber (72;172) defined therein and at least one outlet opening defined therein in communication with the subchamber (72;172), the peripheral wall having at least one opening defined therethrough in communication with the at least one outlet opening of the insert (34;134) and with the cavity to provide communication between the subchamber (72;172) and the cavity; and the outer body further having: a pilot injector hole defined therethrough in communication with the subchamber (72;172) and sized to receive a pilot fuel injector, an ignition element hole defined therethrough sized to receive an ignition element in communication with the subchamber (72;172), and a main fuel injector hole defined therethrough in communication with the cavity, spaced apart from the insert (34;134) and sized to receive a main fuel injector, characterised in that: the insert (34;134) is surrounded by the peripheral wall such as to be outwardly offset from the cavity with an inner end of the insert (34;134) outwardly offset from an inner surface of the peripheral wall, and a portion of the peripheral wall extends between the insert (34;134) and the cavity such that the insert body (34;134) is not directly exposed to the cavity, the at least one opening in the peripheral wall being defined in that portion of the peripheral wall. two axially spaced apart end walls; a peripheral wall extending between the end walls and defining an internal cavity therewith for receiving a rotor therein; an insert (34;134) received in the peripheral wall, the insert (34;134) having a pilot subchamber (72;172) defined therein and at least one outlet opening defined therein in communication with the subchamber (72;172), the peripheral wall having at least one opening defined therethrough in communication with the at least one outlet opening of the insert (34;134) and with the cavity to provide communication between the subchamber (72;172) and the cavity; and the outer body further having: a pilot injector hole defined therethrough in communication with the subchamber (72;172) and sized to receive a pilot fuel injector, an ignition element hole defined therethrough sized to receive an ignition element in communication with the subchamber (72;172), and a main fuel injector hole defined therethrough in communication with the cavity, spaced apart from the insert (34;134) and sized to receive a main fuel injector, characterised in that: the insert (34;134) is surrounded by the peripheral wall such as to be outwardly offset from the cavity with an inner end of the insert (34;134) outwardly offset from an inner surface of the peripheral wall, and a portion of the peripheral wall extends between the insert (34;134) and the cavity such that the insert body (34;134) is not directly exposed to the cavity, the at least one opening in the peripheral wall being defined in that portion of the peripheral wall. a pilot injector hole defined therethrough in communication with the subchamber (72;172) and sized to receive a pilot fuel injector, an ignition element hole defined therethrough sized to receive an ignition element in communication with the subchamber (72;172), and a main fuel injector hole defined therethrough in communication with the cavity, spaced apart from the insert (34;134) and sized to receive a main fuel injector, the insert (34;134) is surrounded by the peripheral wall such as to be outwardly offset from the cavity with an inner end of the insert (34;134) outwardly offset from an inner surface of the peripheral wall, and a portion of the peripheral wall extends between the insert (34;134) and the cavity such that the insert body (34;134) is not directly exposed to the cavity, the at least one opening in the peripheral wall being defined in that portion of the peripheral wall.