just replaced ignitor, PN 4391996. OEM part had chipped piece on ceramic base at end of mounting slot. Assume may have been from thermal expansion.
New part, also OEM, exact match. Clamping appears to be "vibration" resistant, e.g., not easy to turn.
Just tightened screw so snug (ceramic tight to the mounting bracket).
One cycle & works.
How tight should the screw be? Need to recheck after a few runs?
thanks in advance