Hey guys,

Just had one of my DA-70's making a ticking noise which I thought was odd. Then in flight was doing an inverted flat spin at idle and then the engine shut down. I couldn't hear it that well as another pilot was flying one of his planes. I dead sticked it in and was going to increase my idle and went to go start it but the prop wouldn't spin 360 it would get stuck in a spot. Pulled the mufflers and saw both pistons were all scored up.

My question to you guys is what is the cause of this? I run my engines all redline 40:1.

I am glad I wasn't in a hover a few feet off the ground the previous flight.

Just trying to figure out preventatives.

Thanks

Any number of things,ring could have stuck and broke,but that is hard to believed using redline.The bearings hard surface might have started to flake away and got in between the cylinder and piston.My bet would be the bearings went south due to the clicking you heard.

Send it to DA, let them fix it.

Yeah ok. Yup it's on its way. Hope it's covered under Warranty.

As long as the warranty hasn't expired and not user induce I'm sure it will be.

Yeah I agree. I did everything stated in the manual.

but it was lean and caused a seize

Most of the time you can get away with a lean run with redline.It will just get hot and stop then can be restarted after it cools with out any damage,as long as it isn't repeated.The key factor here is that he had rod knocking noise.Being that china is running this country out of the bearing business it is bound to happen to any engine.

Guys,

Got my engine back. Upper needle bearing let go. So I am breaking in basically a new engine. I noticed on a few flights when in idle doing a flat spin the engine on high idle would drop down all of a sudden like it is going to die and then returns back where it was. It happened after in the flat spin for awhile not entering the maneuver. Then noticed couple times throttling up it paused a second. Adjusted the needles a bit and the last flight of the day seemed the best so I don't know if it is a combination of tune and or break in process. Maybe loading up a bit? It just catches me off guard when the idle is high and out of no where it sounds like the engine just quit but them returns???

Thanks for the follow up,so many have problems but never hear of the fix.You would think the high idle would take care of any carb setting,unless it was way off.

Every engine manufacturer is at the mercy of bearings and other parts that are bought
outside. the next 70 you buy will likely not have this issue. Stuff happens...................

I like a FAT engine tune. Not so fat it burbles WOT, but just enough in the mid range! Makes for happier engines no matter what oil you run.

Originally Posted by funboy

I like a FAT engine tune. Not so fat it burbles WOT, but just enough in the mid range! Makes for happier engines no matter what oil you run.

correct, a proper tune will never seize and engine. we fly where the sun shines all year and temps are always over 75f so a slightly rich tune accommodates our long hovers and harrier moves without over heating or leaning the engine. don't blame the bearing mfg for running lean and mean