Engine Mount to Engine Bolt Torque Specification

[Brett H]

I realize that I am joining this discussion late.

When I attached my engine mount to my 912 ULS two years ago the KAI directed one to the Rotax Heavy Maintenance manual for the torque specification. Which was 40 Nm and no Loctite.

The updated Rotax Heavy Maintenance manual (second edition, revision 0, dated September 2022 71-00-00 page 20) now states that the torque specification is 60 Nm AND Loctite 243 is to be applied.

A dramatic change. Does anyone know why this change was made? This seems to have been little formal notification of this change.

To implement this change on a flying plane, I’m assuming that the best way to make this change is to remove one bolt at a time, take care not to let any shims fall out, reuse the bolt if it looks fine, apply the Loctite 243 and install to the 60 Nm torque specification. Finally, adding the “Inspection Paint Stripe” on the head of the bolts addresses the ongoing inspection requirement.

Agreed? Thoughts?

Thanks.

Brett
Columbus, IN

[Bob Y]

I shared this in the earlier post on this subject. I’ll just repeat what was told to me on the Rotax Owner Forum by the Rotax dealer in British Columbia:

“The correct torque specification is 60 NM, and it should be accompanied by the use of Loctite 243.”

[thiggins]

FYI…

Having just mounted my engine (yay!) I actually just spoke with an expert at a certain Rotax place in the “Sunshine” state that recommended not doing 44 ft/lbs with Loctite. He was more comfortable with around 30 ft/lbs sans Loctite. That’s what I did.
Stripped threads was the main concern.

[jrtens]

Originally Posted by Brett H

To implement this change on a flying plane, I’m assuming that the best way to make this change is to remove one bolt at a time, take care not to let any shims fall out, reuse the bolt if it looks fine ...

Columbus, IN

If you are convinced that you need to do this, perhaps new bolts is a better idea?

[JBPILOT]

Due to wife's health, I have not been on here for months, but thought I would add a note. I ordered my kit day one in 2008. I went thru all the original problems of loose engine mounting bolts. On my own, I torqued my bolts to 30#, and used Blue Loctite, and paint marked the bolts. I believe I recall correctly that I have 1,495 hours on mine. Never a problem again. Hope this helps.

[N8DAV8R]

Originally Posted by Brett H

Finally, adding the “Inspection Paint Stripe” on the head of the bolts addresses the ongoing inspection requirement.

Not exactly. If the bolt breaks your paint stripe lies.

[Brett H]

The callout to use Loctite 243 seems to come from Rotax SI-912-033.

This SI speaks of a potential casting issue that may cause a leak / weep at the tapped holes for the engine mount bolts. The Loctite 243 is to address this.

Brett H
Columbus, IN

[Bob Y]

Looks like for engines within the past two years.

[thiggins]

https://rotax.my.salesforce-sites.co...AB?asPdf=false