this O-235-C1 is new to me. I've overhauled several lycomings over the years and the thru bolts are always tight fitting so I can easily slide the right half of the case on to the other. With this -C1 the thru bolts are loosey goosey and won't stay in place. My concern is how to fit the case halves together and still insure that the 0-rings will not be compromised. Also wondering why the thru bolts have one end threaded at 1 3/4" and the other at 3/4". Nothing in the O/H manual. Any help/direction appreciated for an old Norwegian in SD.