Hi I have about 50 flights on my DA50 with a 23 x 8 bolly, Run in on mineral and now on synthetic opti 2, 80 to 1. I have had no probs with this engine but today I started the motor with a strange noise, almost like the spinner was loose. The motor runs fine but with this metalic rumble most niticable at idle.

After inspection all seems tight. Bearings feel fine. The noise can be replicated when the piston is at top dead centre. The motor is a 2 yrs old and supposed to have the updrated con rod. Could the conrod bearing be damaged?

Does anyone have any idea what could be the cause before I send it off?

Sounds like the wrist pin

Sonicboom,
I think 2 year old engines are not updated. Did you send it back for the updates after you bought it ?
Mine has only 5 flights on it and has a clicking noise when I turn the prop by hand. I did a thread here in RCU, and it turned out to be the ring moving in the piston. According to some people, nothing to be worried about.
Andres

When you rock the prop tips back and forth on compression, you should get about 1 1/6" play back and forth..when the engine is hot you may get about 1/8" but as the engine cools it should go back to about 1 1/16"...

When the wrist pin started going on my first one you could hear a high-pitched metallic ringing in the air and on the ground..my second one hasnt had any problems but it came with all the updated parts.

I know this may sound foolish but after I started flying mine this season I just started it up and flew it thinking all was well as i had 20 hours on the plane last season. It started to sound like the muffler was falling off after the 3rd flight and when i looked it over all seamed ok so i went up a 4th time and did a high speed pass and it gor louder when i landed all 4 prop bolts where busted the spinner was all that was holding the prop. Seems the wood dried up and shrunk over the winter on my prop and things got loose.