912iS Engine Mount Bolt Size

I've just mounted my brand new 912iS engine to my Sling 2 project -- woohoo!!

The Sling Aircraft factory (TAF) supplies four M10 x 130 mm 8.8 bolts to pass through the standard Rotax ring mount, cup washers, distance spacers and rubber cushions and airframe engine mount. The M10 bolts are a very loose fit through the Rotax ring mount and my aeronautical engineer, aircraft designer friend (winner of 2 Lindy Awards), who helped me today, was quite concerned.

Are the M10 bolts ok for the ring mount? That's what's specified in the Sling 2 factory maintenance manual. There are several hundred Slings flying and more than a few for almost a decade with thousands of hours - some over 6000.

I don't want to second guess the design, just kind of looking for a touch of reinforcement.

Thanks.