What do yall think could have caused this?

[pioneerguy600]

I have some cyls that I can take a pic and show you. The piece that's missing is normally just offset from the center of the port coming down from the roof. Similar to the failed piston pic.

Sent from my XT1635-01 using Tapatalk

Possibly the 046 isn't like what I'm talking about. But most older Stihls have this in the roof.

Not on the 046 or MS460. The 038 does.

 

[TLG]

Got it. Thanks Pioneerguy[emoji106][emoji106]

Sent from my XT1635-01 using Tapatalk

 

[pioneerguy600]

I have seen two cases much like the OP`s where ingested metal parts have lain up against the piston until it cut through the piston skirt. The damage was only to the piston and did not affect the cylinder at all, a new piston and rings in both cases put the saw back in working condition. The nut the OP is showing is most certainly what caused the piston damage.

 

[huskihl]

Now that's a better pic. The ring Tucker tear drop is totally gone from the roof of the intake. It looks as if someone has widened the crap out of that intake port Wondering if the tear drop broke off or it was ground out? Either way throw that pos away no matter how good the bore looks.

There’s no teardrop in an 046. Cylinder looks stock to me. Just needs the scuffing removed

 

[TLG]

Jk, Lonestar, Pioneerguy and Huskihl were 100% correct. This is the teardrop/ring Tucker.
044 early D chamber
066
Both do not use the tear drop.
028 and 034 both use the teardrop/ring Tucker.
It is the small piece coming down from the roof. Life is good and I'm STIHL learning. That's why I like this site. Guys aren't afraid to help out. Here are some pics.

 

[pioneerguy600]

Stihl could do away with that drop down ring tucker by moving the ring keeper pins , they staggered them to just outside the intake opening/port, the ring ends always ride against the cylinder walls and don`t cross the port opening or the transfer openings.

 

[Jkstihl]

Possibly the 046 isn't like what I'm talking about. But most older Stihls have this in the roof.

Doesnt look like anything has been broken off. Ill get better pica

 

[Jkstihl]

I have seen two cases much like the OP`s where ingested metal parts have lain up against the piston until it cut through the piston skirt. The damage was only to the piston and did not affect the cylinder at all, a new piston and rings in both cases put the saw back in working condition. The nut the OP is showing is most certainly what caused the piston damage.

Bro thanks for confirming my hunch...ive narrowed down the possibilities but just couldnt believe it.

 

[Jkstihl]

Just some random pics of the 046 throughout the rebuild stage. Thanks for the help fellas this is my first rebuild but i been doing tree work for 13 years

 

[clemsonfor]

Nice black arm. Do you have a blade for it?

Sent from my moto g(7) using Tapatalk

 

[Jkstihl]

Yeh just set that L screw in a little extra and get that chain moving and that’s all you need[/QUOT


Thats actually what exactly happened man...there is evidence of it pinging against the closed throttle plate

 

[Jkstihl]

Nice black arm. Do you have a blade for it?

Sent from my moto g(7) using Tapatalk

 

[LonestarStihl]

Well that’s something

 

[Jkstihl]

Clemsonfor this is before i sanded and flat blacked it

 

[Jo3]

Someone ported the saw in the wrong hole. Too regular for a crack.

 

[Jkstihl]

Someone ported the saw in the wrong hole. Too regular for a crack.

Haha

 

[Jkstihl]

Ordered a chinese carb and this is what all they sent me...gonna use ngk plug tho

 

[farmer steve]

Just in case anyone is interested I had this in my files.

 

[Jkstihl]

Just in case anyone is interested I had this in my files.

Holy ****....thanks man this confirms my theory even more.

 

[farmer steve]

Holy ****....thanks man this confirms my theory even more.

I didn't know if anything in there might pertain to your particular issue. Hope ya get your saw figured it and running soon.