Lycoming SB 634 Cylinder Head Cracks

[tgmillso]

Hi All,

This Mandatory SB affects parallel valve engines shipped in 2013-2015 (specific dates in the document), which I suspect would be many people on the forum that purchased their engines direct from Van's/Lycoming. Cracks are known to occur in the cylinder head, requiring scrapping of the cylinder. Lycoming outlines briefly the situation in the document below.
https://www.lycoming.com/sites/defau...Retirement.pdf
The details were a little light on, so I did a bit more digging and it appears that the CAA in New Zealand published a document with more detail covering the issue back in April 2018.
https://www.caa.govt.nz/assets/legac...CAN-85-009.pdf
With 14 hours on my engine I've already had to replace the mechanical fuel pump due to another SB, the supplied Sky-Tec starter motor relay has failed and now this. To say I am mildly crushed would be an understatement, and this is yet another issue that pushes me in the direction of making the next RV all electric.
If anyone has details that they can add to this, especially around mitigation and root cause, it would be greatly appreciated.
Regards,
Tom
RV-7
YIO360-M1B