Here's a question for those of you that have removed the harmonic balancer and the timing gear cover on a 2F engine to reinstall a new crankshaft seal in the front of the timing cover - can anyone tell me what the round metal "insert" is that is behind the rubber seal in the timing cover? The "insert" appears to be very coarse threaded along the inside opening but the end of the crankshaft (which is smooth) fits through the hole so nothing is threaded into the "insert". So what purpose does this thing serve? A mystery that needs an answer ..... Only thing I can think of is it simply a "backstop" for the seal -- to keep it in place when the harmonic balancer is tightened down? If so, why is the thing threaded?