Hi John, Next week, my AP and I will be addressing the motor mount bolt torque issue, the right exhaust-cowl contact and checking each cylinder for valve/valve train problems (when he has time to further explore the etiology of increased engine vibration). He will have 3 different torque wrenches on hand to make sure a torque wrench is not at fault. The engine in my Aircoupe is a C90-16F. The rubber motor mounts we removed were the same as the new ones. With 60 inch pounds of torque, the engine case was in contact with motor mount and the flat washer beneath the nut had completely flattened out the rubber mount.
Thanks, David N95CV --- In [email protected], John Cooper <j...@...> wrote: > > On 8/15/2010 10:52 PM, drdlhammond wrote: > > How can I/we tell if the rubber motor mounts are bad??? > Good question. I guess one answer would be "if you can't get the proper > torque without metal-to-metal contact..." > > If you use the proper hardware, you should be able to go to 60-80 inch > lbs and still have roughly 1/8" clearance between the front of the ear > of engine casing and the front washer as well as between the surface of > the engine mount and the rear of the case ear. > > At the risk of asking a stupid question, are you sure you have the right > mounts? The O-200 style cases will not accept the conical mounts and > there were C90-14F and a few C85-14F engines that require the same > mounts as the O-200. > > If the exhaust touches the cowl, correct that before you spend a lot of > money on other issues. > > Mags, spark plugs, and valve train issues can cause vibration by making > the engine run "rough", e.g. produce less power from one or more cylinders. > > -- > John Cooper > Skyport East > www.skyportservices.net >
