455 Rancher Ring Catch

[Bob Hedgecutter]

Husqvarna 455 Rancher- are these things prone to ring catch in the transfers?
This is the second one I have been presented with that died in similar circumstances- almost like the ring became gummed (carbon?) into the intake side, near the locator pin and the other side has been forced out enough to catch a port, breaking the ring, gouging the cylinder and chunking the piston.
No air leak, no bearing failure, no lean condition scoring- just a busted ring and gouged cylinder.

Anybody seen similar?

 

[huskihl]

That is debris from inside the motor or it injested something through the intake

 

[Bob Hedgecutter]

That is debris from inside the motor or it injested something through the intake

Bearings, bottom end and all usual suspects are like new still- cannot find anything missing on the intake tract- so unless somehow something was introduced through the intake tract from an outside source- we might beg to differ on this one.

 

[Bustech17]

I've seen this a couple times in the past, mostly on XP units. Even thought the 455 isn't an XP unit, it has the XP posting just like the old 55's did. One issue was the cylinders made by Mahle had ports that weren't chamfered enough and the ring would catch after about 20 to 35 hours of use. Kind of hard to distinguish from the pictures, but that's about my only guess as the locator pin shouldn't really be that close to the port. I could be wrong. It has been a few years.

 

[Bob Hedgecutter]

I've seen this a couple times in the past, mostly on XP units. Even thought the 455 isn't an XP unit, it has the XP posting just like the old 55's did. One issue was the cylinders made by Mahle had ports that weren't chamfered enough and the ring would catch after about 20 to 35 hours of use. Kind of hard to distinguish from the pictures, but that's about my only guess as the locator pin shouldn't really be that close to the port. I could be wrong. It has been a few years.

Do not know- what I do know is this one stopped and I was the first to open it- no foreign bodies apart from bits of ring- all bearings, cages and shells complete and undamaged, nothing like a plate screw out of place, no other debris in muffler/crankcase or cylinder- no dings on top of piston and no damage to the squish band.

The other one I looked at recently- it was taken to a repair shop, owner told needs new cylinder and piston, owner took it home and tried to get it running again and then I got to see it- so Lord knows, but it was the same in the respect of no other bearing type damage.

 

[huskihl]

Bearings, bottom end and all usual suspects are like new still- cannot find anything missing on the intake tract- so unless somehow something was introduced through the intake tract from an outside source- we might beg to differ on this one.

I originally didn’t see your 1st pic. Still odd that it did it in the transfer rather than the exhaust port which is 2-3x wider

 

[Bob Hedgecutter]

I originally didn’t see your 1st pic. Still odd that it did it in the transfer rather than the exhaust port which is 2-3x wider

Oh I agree- its odd and I do not deal with a lot of 4## saws- but this is the second one in fairly quick succession that died in similar circumstances.
Thats why I asked if anyone else had seen similar and if it was a "common thing" for these.