Did I burn anything else beside the glow plug on OS 50 Hyper?

[dtdc728]

3 weeks ago, I started breaking in my OS 50 Hyper in Trex600 by letting it idle on the ground. Used up 1 tank and back plate was warm to the touch. I started having problems with hydraulic lock due to excessive oil in Align muffler. Today, I wanted to continue with the break-in by hovering. Engine didn't sound rich but there was smoke, not as much as first tank. While in hovering, there was a pop sound and a smell of burned plastic. Engine quite during hover but landed safely. I removed the plug and it was a little loose (did not use any force to unscrew it). The plug's element burned up to hell and looked back. So did I burn the piston in the process? Do I need to remove the engine and its head to diagnose? I was using the os #8 plug with the high speed needle about 1 full open with 2-3 clicks on a warm sunny day. 1st tank was on a cool cloudy day. 2nd tank was on a warm sunny day. My elevation is about 700ft above sea-level. Any help is greatly appreciated.

[TheBum]

Get a flashlight and look in the glow plug hole while the piston is down. You'll be able to see if there's a hole in the piston.

[lionc]

It's seems too lean... For a Breaking in, I have the high speed at 2.5 turns. In the manuel it's said 1,5 turn from the normal position. Normal position is about 1 turn more or less.

If your back plate is warm, it's too lean.

[MXRACERX43]

Check your headbolts, bet they are loose, probably the popping sound you heard. While you are there do it right and disasemble the engine and check for scoring/ signs of a lean run.

[dtdc728]

thanks for the replies guys. I looked through the plug hole and saw what I feared initially. There is a freakin hole In the piston. Looks like an overhaul job. Might as well change to boca bearings while I'm in there. Should I change anything else beside the piston?

[DavidH]

Mixture was too lean, that is what caused the hole to burn in the piston.
Idling an engine with the heli on the ground is not going to break in an engine. Break in of an engine requires that it goes thru heat cycles. Warms up and then cools off. On a new engine it is best to just fly the model with the mixture set just a tad to the rich side. On the OS Hyper 50 from my experience 1 3/4 to 2 turns out from fully closed on the main needle is usually a little rich. Most I have messed with seem to fly just fine at 1.5 turns out from fully closed when using 30% fuel.

Send the motor to Hobby Services if you bought it in North America and have the reciept. They will repair or replace the engine under warranty even thou it was your mistake.

David

[dtdc728]

Thanks for the heads-up DavidH. I'll do just that. In the mean time, I might buy another engine for my 600N so I won't waste the sunshine here in Oregon (not too much sunshine throughout the year). Should I stick with OS or should I get TT Redline or Ys? By the way, I want to thank all of you guys who took the time to donate your advice. Helifreak is awesome.