Engine Squeak

Resurrecting this thread, I have a new engine (8 hours now) with rather severe gear-dog (face-cam) squeak when hot and turned over by hand. The squeak is a juddery screeching, amplified by an all-carbon lightweight prop and quite alarming. Not present when cold and more or less not present up to the like-for-like oil change at 6 hours.

Oil is Skydrive Aerolube (previously approved by Rotax), 10w40 semi-synthetic API SL, JASO MA2. Its manufacturer confirms around 1000ppm ZDDP (probably up to the API 1200ppm "limit"), to which another 1000+ppm has been added by ZDDP additive, with a small positive effect on the screech, but still worrisome.

For comparison, Shell report 2000ppm ZDDP for AeroSport4.

 Edited to say that gearbox friction torque is 432 in.lbs cold.

Any collective thoughts on this, other than what is above?

Duncan.

Hi Duncan,

The gearbox squeak is fairly common with newer engines and will go away after a while. It's normal and not an issue.

Roger,

Thanks for the reassurance.

It has now been pointed out (by those on the ground) that the squeak is a continuous whistling-howl when in flight (which can't be heard from the cockpit). So I'm still alarmed.

Separately, a Sportcruiser here has a similar effect periodically and the gearbox is currently being stripped/examined for defect; I suspect nothing will be found!

Duncan