First annual with plane, extremely low compression Lycoming IO-360

alfadog said:
Google oversized helicoil (heli-coil, thread insert). Again, don't know if these are used in aviation but might could save the cylinder. Also, call a cylinder shop for their advice.
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alfadog said:
Google oversized helicoil (heli-coil, thread insert). Again, don't know if these are used in aviation but might could save the cylinder. Also, call a cylinder shop for their advice.
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I've seen some A65 cylinders with some large threaded inserts in them. Presumably someone decided it was legal to install them. That might be an option or welding might be one too but both those fixes are likely outside the scope of the average mechanic. At some point it might be cheaper to look at replacement cylinders...
 
benyflyguy said:
How does that happen??
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I wouldn’t be surprised to discover someone overtorqued the spark plugs. I’ve also seen some Lycoming cylinders that had a crack in the head starting at the spark plug hole and progressing out from there. A crack could cause the helicoil to become loose and start pulling out.
 
I fly in some terrible conditions; even night IFR in the mountains, but I wouldn't fly behind a motor with helicoils holding the plugs in.
 
FORANE said:
I fly in some terrible conditions; even night IFR in the mountains, but I wouldn't fly behind a motor with helicoils holding the plugs in.
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It’s my understanding all motors have it. It adds strength to the aluminum heads
 
Spark plug that came out of that cylinder. Never went back in, we were replacing them.
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The cylinder manufacturers must have it sorted as I haven't heard of spark plugs blowing out. having witnessed spark plug blowout using helicoil in a non aviation application I would be looking to replace the cylinder rather than what oversized helicoil is available.
 
FORANE said:
The cylinder manufacturers must have it sorted as I haven't heard of spark plugs blowing out. having witnessed spark plug blowout using helicoil in a non aviation application I would be looking to replace the cylinder rather than what oversized helicoil is available.
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they known as cylinder savers. a steel insert that are screwed into a milled out spark plug hole.
 
I believe these aluminum cylinder heads all have stock/factory “helicoils”.

I also believe the replacement helicoils need to have serrated teeth on some applications, to prevent said fear of blowouts.

Signed,
Not an IA or A&P
 
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