flyrotary@lancaironline.net Mailing List Archive

Chris,

My recommendation is to get one of the large ¾" (900 + ft – lbs) air wrenches. I got one for $99 and it earned its keep the first time I had to get the big nut off. 2 seconds and it was loose. In fact, had a gent load his rotary in his car and drive 90 mile round trip to my hangar – for the 2 seconds it took to get his loose as well. He had spent three days trying to stabilize the block and using a pipe on a wrench ( as well as many of the methods you attempted) to get it loose, all which failed.

Believe, me you'll love it for that purpose alone – not counting all the other uses. I had a smaller ½" 300 ft-lb air wrench but it just wasn't up to the job.

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.dmack.net/mazda/index.html

For those who wish to use the nut again but have difficulty removing it, heat any flat on the nut with an Acetylene Oxygen medium tip, to pink.

This makes the nut bigger than when it is cold, and will fail the Locktite if any was used. With a long punch, and a light fast moving hammer, drive the nut loose. I have never had this not work since 1980.

To install the nut, place a deep socket between the head of a case bolt and the counterweight to prevent the counterweight from turning. Place a small drop of red Locktite on your finger. Wipe the area where the nut will touch the counterweight with Locktite. A small drop because Locktite on the bearing will glue the bearing to the crank. So, no Loctite on the taper at all. Warm the nut to the point that is uncomfortable to hang on to. Spin the nut on the shaft, slip on the socket and spin up the 1/2" drive impact gun at 120 pounds of air pressure, and hold the trigger down until the nut stops turning, and then a few seconds more. There you go. Over 350 foot pounds of torque. And it tightens up a bit when it cools, and it is Loctited. Never use the soft locking washer. It extrudes over time releasing some of the torque load on the nut. Duh................

I have never had one come loose, even with the shock loads of a dog ring transmission. No tears, no injuries, no failures.

Lynn E. Hanover