Total engine failure. Piston bearings
Henrik Holm Kristensen
Please be careful with the amount of play in the piston bearings.
We had a very bad damage to out engine of total hours of only 83.
The engine had the software update to lower the load on the piston rod bearings at approx 43 hours.
This software update should make the possibility of a bearing damage at the the upper piston pin lower.
Unfortunately the damage must have been started in the fist 43 hours of operation, and finally led to the
total breakdown of the bearing.
The bearing is of the needle type. And all the needles of the bearing was introduced at the breakdown of the bearing to the rest of the internal parts of the cylinder, and caused severe damage to the piston and cylinder.
We have noticed after the rebuild of the engine, that the play is now so small, that when trying to turn the engine by pulling in the tip of the propeller, no play what so ever is to be noticed.
Before the damage, a very noticeable play could be observed by turning the engine by the tip of the propeller by hand. And a small "knock" "knock" noise could be heard from the engine, when turning the engine fort and backwards.
We have now made the procedure to take out a sparkplug at the 25 hour service interval, and check the play in the upper piston bearings.
Best regards
Henrik Holm Kristensen
Arcus no 58.
b.aronsson
Hi Henrik,
Sorry to hear about your engine damage, but very interesting for others as us to know about.
How did you measure the bearing play? And did you get any limits from Solo?
I just measured ours according to the Rotax procedure ( https://legacy.rotaxowner.com/si_tb_info/serviceb/sb-505-01r1.pdf )
Our engine has 88 h and got the new mapping according to TN 4600-6 at 70 h
Forward cylinder: 0,020 mm
Rear cylinder: 0,030 mm
