SonexBuilders.net

http://jabiru.net.au/images/JSB031-2_En ... _Bolts.pdf

This just came up on the Jabiru board. Seems we might be facing some serious downtime and expense.

I did the JSB031-1 SB two years ago and I think I'm covered until overhaul, but looks like if you didn't, you need to do the entire through bolt replacement, which means a complete tear down.

Just got done reading the AD. Sounds like a serious repair if people decide to go through with it. They sure seem to emphasize the need to have a "professional" Jabiru mechanic perform the work, which I guess is best. They also call for a lot of inspection of the cylinder areas. Have there been issues there as well?

The cylinder inspection is due to interference by the shoulder of the nuts on the flanges of the cylinder barrels. Some of the barrels were not machined to clear the shoulder of the nuts so it put stress on that area. If you have cylinders that do this, you need to grind off the shoulder of the nuts to clear the interference.
When I replaced my nuts with the 12 point ones, I didn't have this issue.
Since I replaced my nuts before the latest SB, I'm clear of to keep running "legally". I think I'll order the through bolts and have them on hand in the event I ever have to pull a head. Then I might just replace the through bolts at that time and not worry about the studs. It seems the only reason to split the case is to replace the studs.

I'm just formulating how to inform my hangar mate. He recently finished his annual with the original nuts on his plane. This SB will require him to do the tear down. It will probably make him sell the plane.

I just done a major overhaul on my 2200 jab I bought full set of though bolts then decided to only replace the long bolts buy when I was removing the cylinders I could see oil on the casing join not enough long bolts to hold the casing. I had no choise had to split the casing I am not a lame just a mechanic you can do it yourself but it is a bit tricky.