My friends DA 85 was purchased two years ago. He has a Ziroli he built over 10 years ago with a Brison 5.8 in it. No problems and great performance. I have a Robart with a Brison 5.8, no problems. I think that DA tried to pare the weight down in the 85 since it is a pretty light engine for it's size. Back in the olden days
Webra and Hirtenberger did the same thing with their pattern 60s. I still have a Webra Speed 60 that runs like stink and you have to check all the bolts after each flight because of vibration! My friend sold his DA 85 after it shook apart a Robart 47 and caused it to crash. He built another one and installed a BME 106? at an angle after seeing the same thing done by Evan Quiros at War Birds Over the Rockies. The engine center line is slightly lower in the cowl but if you install the fake motor correctly it is hardly noticeable. The performance and sound is awesome!
Larry