An ignition device with a pre-combustion chamber of an internal combustion engine having a plurality of cylinders each defining a main combustion chamber, the ignition device comprising: a first pre-combustion chamber part configured to at least partially accommodate a spark plug, the first pre-combustion chamber part including a first end flange, and a first annular protrusion extending from the first end flange, the first annular protrusion including a first thread provided on a circumferential surface of the first annular protrusion; and a second pre-combustion chamber part defining at least a portion of the pre-combustion chamber and including at least one orifice configured to be fluidly connected to the main combustion chamber, a second end flange, and a second annular protrusion extending from the second end flange, the second annular protrusion including a second thread provided on a circumferential surface of the second annular protrusion, the first thread being threadably engageable with the second thread; wherein one of the first and second annular protrusions (74, 84) at least partially projects into the other one of the first and second annular protrusions (74, 84), characterized in that the second pre-combustion chamber part is detachably mounted to the first pre-combustion chamber part, such that the first and second pre-combustion chamber parts (70, 80) are axially secured to one another and rotable with respect to one another as, and after the first and second pre-combustion chamber parts (70, 80) are assembled to one another, the first and second threads (76, 86) are out of engagement; and a positioning device provided at an interface between the first and second pre-combustion chamber parts (70, 80), the positioning device inhibiting, when the first and second pre-combustion chamber parts (70, 80) are assembled to one another and are in a pre-determined position to one another, rotational movement of the second pre-combustion chamber part relative to the first pre-combustion chamber part. a first pre-combustion chamber part configured to at least partially accommodate a spark plug, the first pre-combustion chamber part including a first end flange, and a first annular protrusion extending from the first end flange, the first annular protrusion including a first thread provided on a circumferential surface of the first annular protrusion; and a second pre-combustion chamber part defining at least a portion of the pre-combustion chamber and including at least one orifice configured to be fluidly connected to the main combustion chamber, a second end flange, and a second annular protrusion extending from the second end flange, the second annular protrusion including a second thread provided on a circumferential surface of the second annular protrusion, the first thread being threadably engageable with the second thread; wherein one of the first and second annular protrusions (74, 84) at least partially projects into the other one of the first and second annular protrusions (74, 84), characterized in that the second pre-combustion chamber part is detachably mounted to the first pre-combustion chamber part, such that the first and second pre-combustion chamber parts (70, 80) are axially secured to one another and rotable with respect to one another as, and after the first and second pre-combustion chamber parts (70, 80) are assembled to one another, the first and second threads (76, 86) are out of engagement; and a positioning device provided at an interface between the first and second pre-combustion chamber parts (70, 80), the positioning device inhibiting, when the first and second pre-combustion chamber parts (70, 80) are assembled to one another and are in a pre-determined position to one another, rotational movement of the second pre-combustion chamber part relative to the first pre-combustion chamber part.