Danny--

I asked a similar question here on LML several weeks ago and never got an answer. For some reason - probably liability - nobody seems to publish anything to do with prop torque values. I did find McCauley Service Bulletin 227B which lists torque values for their propellers. Not knowing the proper torque for my particular engine, after changing the front crankshaft oil seal on my Lycoming O-290-D2, I torqued the 7/16" prop extension bolts to 40 ft. lbs. which seemed "really tight" to me - I didn't want to pull the threads out of the lugs. A standard socket wouldn't fit in there, so I used a crow-foot extension and calculated the adjusted value. Also, I lubricated the threads with anti-seize which, apparently, is another issue in itself. According to the link above, whether or not you should lube the threads is "engine specific". Lycoming (according to the link above, again) recommends installing the bolts dry, but I thought that was asking for trouble when it comes time to change props. So if a couple years from now you read about my prop departing the aircraft, please forward this comment and photo to the NTSB. /sarc

P.S. My A&E said the prop flange bolts should be safety-wired with .041 safety wire, the larger size.




On 1/13/2014 6:00 AM, Lancair Mailing List wrote: