DLE 170 dead cylinder and piston

[thurmma]

Judging the discoloration of the mating surface between the crankcase and that cylinder, the gasket was moving around and the cylinder bolts were not tight or they loosened up just enough for the gasket to lose its seal,,, the rest is history.

New top end and several cans of carb cleaner to get all that very fine metal bits out of the bearings and you should be fine.

I did notice that the bolts while snug, were nowhere near as tight as the other side so I believe you hit the nail on the head. I have a GP-176EVO coming and will rebuild this one and put it back in my 42% Pilot Edge for a backup/free style plane

Thank you for the input.

 

[thurmma]

Mark I am curious as to what exactly is the cause my self.

I believe @Bill Vargas hit the nail on the head with his analysis of the mating surfaces. I also noticed that the bolts weren't anywhere near as tight on the right jug as they were on the left jug when I took it apart. I have a GP 176EVO coming for the 330LX and will rebuild the DLE for the 42% Pilot Edge as a backup/freestyle plane Nothing like having 2 40%+ size planes in the hanger to make me feel good.

 

[Bill Vargas]

Hey thurmma, I had similar issue, same as yours, happen to me on one of my 3 dub's and caught my eye when I was done for the days worth of flying,,, post flight inspection if you will and saw a base gasket squishing out. So I snapped a few pics and sent them to the "G" man and he called me back with the mod/fix for that issue. I now use a thin coat of YAMABOND 5 sealant on both sides of the gasket along with the "dimple" mod. pics of what a moving gasket looks like and its deformed appearance when removed and compared to new ones.

The indicator to me that something was up,,, a black oily residue appearance between the jug and crankcase.

 

[49dimes]

I believe @Bill Vargas hit the nail on the head with his analysis of the mating surfaces. I also noticed that the bolts weren't anywhere near as tight on the right jug as they were on the left jug when I took it apart. I have a GP 176EVO coming for the 330LX and will rebuild the DLE for the 42% Pilot Edge as a backup/freestyle plane Nothing like having 2 40%+ size planes in the hanger to make me feel good.

Hey thurmma, I had similar issue, same as yours, happen to me on one of my 3 dub's and caught my eye when I was done for the days worth of flying,,, post flight inspection if you will and saw a base gasket squishing out. So I snapped a few pics and sent them to the "G" man and he called me back with the mod/fix for that issue. I now use a thin coat of YAMABOND 5 sealant on both sides of the gasket along with the "dimple" mod. pics of what a moving gasket looks like and its deformed appearance when removed and compared to new ones.

The indicator to me that something was up,,, a black oily residue appearance between the jug and crankcase.

View attachment 49269

So the conclusion is.....Lose cylinder bolts allowed the cylinder to "tilt" causing the piston ring to snag on the exhaust bridge and then pretty much eat itself???

 

[Bill Vargas]

well that depends on the damage that occurred,,, did the piston melt or did something break off and,,, etc.

In this instance, as evident by the grey color of the spark plug, the piston melted due to a lean condition because of the gasket losing its seal.

 

[49dimes]

well that depends on the damage that occurred,,, did the piston melt or did something break off and,,, etc.

In this instance, as evident by the grey color of the spark plug, the piston melted due to a lean condition because of the gasket losing its seal.

And just to be accurate......Same loose bolts / gasket caused the tuning issues prior to his carb change out ? I want to help get my friends DLE 60 sorted out and he has already been advised to get a new carb but it appears it may simply be loose bolts.

 

[thurmma]

Same loose bolts / gasket caused the tuning issues prior to his carb change out ?

We won't know for sure until I get it back together later in the spring but, I am betting that was the issue. If I didn't have another engine on the way already, we would know sooner

 

[thurmma]

The anticipation of the GP 176 EVO is killing me! It is supposed to be sunny and 60+ this Sunday with light winds and I have nothing to fly It sucks that I have been flying in sub 40 weather with 10 - 15mph winds and when the sun comes out and wind dies I have nothing to fly.

 

[Bill Vargas]

>>> Same loose bolts / gasket caused the tuning issues prior to his carb change out ?<<<

Yes, due to the engine's air leak,,, more air-more fuel,,, engine run like KAA-KAA,,, bang-engine dead

New locking nuts and gasket,,, for that piece of mind thing. Occasional cowling removal for preventative maintenance helps too

 

[49dimes]

Well I certainly hope he has been following this thread.