Profanity & nylon caged bearings...

[CR888]

I'd try a KOYO (Japan) metal cage replacement. Interesting the comments above about the issues with the 545 & 555 are not seen compared to the 550xp & 562xp. I have a theory the crank stuffers either through heat absorption or oil prevention have something to do with it.

 

[1990Husky262]

ive wondered if it could have some thing to do with the rev boost

 

[wcorey]

Wonder if he ran it with brake engaged or crazy dull chain repeatedly?

You made me go dig it out, still apart in a box from about 4 years ago. Was cleaned up, bearing pressed out, ready to reassemble, just never got around to it. Someday... Too many saws, too little time...
Anyway, clutch, brake band, cheesy plastic oil pump etc. show no sign of overheat or slippage. No clue on dull chain abuse but if so you'd think either the top end would be scorched or the already mentioned parts would tell the tale...

 

[Bob95065]

I rebuilt a MS290 that had lean seizure. When I took it apart there was black sludge in the crankcase. That's when I found that the bearing cage was missing on the PTO side. The bearing was off center and it leaned out. First time I saw that happen before this thread.

I found bearings with nets, cages but I don't remember where. I sold that saw a few years ago.

 

[afleetcommand]

Regardless, you now have a cool project saw....at what point do we run out of room?? (For project saws....) 20-40-100? My closet is it....its to the point if one goes in, one has to leave...

 

[Spike60]

On 562's I have an opinion, not fact; on what and how to help. I think it is heat. They intentionally (same as a lot of later designs) trap exhaust heat for efficiency purposes. The way those transfers wrap around the exhaust & the way the mufflers baffles deflect the exhaust down to the bottom of the muffler. To the rather uneducated eye..it looks like a design trend. SO on the 562's I've done a couple of things to get rid of heat as a priority vs. power....first open the hole in the baffle directly in front of the exhaust port, leave the baffle in, and open up or add an exit. Also on the older ones, cut the top cover similar to the new ones to let more heat out the clutch side. SO far the non contact thermometer says there is a difference....enough to notice, not enough for me to post as absolute fact. Also have always run a heavier oil mix hoping the more lubrication offsets the slightly higher combustion temp. One of the posters here mentioned the stuffers....I also have noticed I've yet to see a 555 or 545 with an issue. Does that lower primary compression along with large case volume flushes & carries oil around to the bearings better?? Maybe cools better? I don't know...but it might. I still want a steel option! AND I notice Stihl has used nylon for years with no issues AND the new OEM replacement cases from Husqvarna come with nylon. I used them on a 372xpw two years ago..its doing fine. Also for completeness of thought acknowledge the fact that there are many 562's & 550's doing just fine and nylon doesn't guarantee failure. Since they all are..nylon, thats all I'm going to see!

Lordy, the engineer's mind is up and running.

A key point is where you say, "yet to see". The 545 and 555 point could be explained by the fact that they sell in FAR less numbers than the 550 and 562. So, I haven't seen them fail either. And since we don't see the thousands of saws that don't fail, they are not factored into conclusions that we may draw from what we do see. Guys just bring us the broken ones. But we see the same failure a couple times and get to wondering...........it's a natural reaction.

I tend to feel the steel cages are better myself. But I have seen both fail, and like some guys said, if a steel cage goes, the top end almost always gets torn up. But if nylon was a real serious weak point, these companies would go back to the steel cages pretty quick rather than pay a lot of warranty claims. If I can get the right guy down at tec service it would be interesting to hear his version of this debate. I will look into that.

 

[Spike60]

I'd try a KOYO (Japan) metal cage replacement. Interesting the comments above about the issues with the 545 & 555 are not seen compared to the 550xp & 562xp. I have a theory the crank stuffers either through heat absorption or oil prevention have something to do with it.

Let's think before advancing this stuffer theory. Stuffers were never a problem on 357's.

 

[Tor R]

Let's think before advancing this stuffer theory. Stuffers were never a problem on 357's.

agree, but.......5xx serie saws is far more compact.
If we take 346 and 550 as example Husky managed to shave of the crank and they managed to get space for stuffers, impressive by itself, but it may reduse the chance to get rid of heat a tad, that is how I think.

Here is a few crank sizes for those who is interested:
254: 147 mm
357: 144 mm
346: 133 mm
550: 122 mm
242: 127 mm

 

[5000+]

Also never saw or heard of nylon cage problems on low/mid hour Stihls. Are Husq nylon bearing lower spec, or is design/straro a factor.

 

[Jughead]

I'm thinking oil and ethanol has a lot to do with the magical evaporative bearing cage syndrome.

 

[Warped5]

I'm thinking oil and ethanol has a lot to do with the magical evaporative bearing cage syndrome.

+1

.... and nylon is, after all, plastic. Plastic, exposed to temperature changes and stress over time, will fail. Just a question of when.

 

[Jughead]

Just about all stihls I get in to fix gets a complete tear down.95% of the time the cages are cracked.the other 5% are stickin to the roof of the combustion chamber and exhaust port.peanut butter must be the main ingredient for the cage material.lol

 

[Spike60]

Late 2015, they made a change on the bearings and crankshafts on all of these saws, including the 545 and 555. They listed the reason as "improved grip". They also changed the pistons, ("profile and ovality") and needle bearings at this time. So............

A, they're not afraid or unwilling to make improvements.

B, they didn't feel that the plastic cage was an issue, or that would have been part of the correction.

The cage may be "what goes", and that's what we see when we tear the saw down. But the cause could well be something else. When a metal cage fails, we don't blame the metal.

 

[afleetcommand]

LOL To clarify things...I'm a truck & plow driver.. And a farmer...sort of a simple type...

And as usual, spike60 puts things in context, the voice of both experience and reason....While observations are just that, the size of the "sample" sets do matter....if I see 4 550's to repair and all have bearing issues, that means 100 percent of my experience is colored by that experience. And there may be 100 other repair situations out in the world of that series and I got the only 4 bearings failures! Then my sample wouldn't be the majority in fact it would be the exception not the rule.... But on the other hand of those "100" other repair cases, 50 were related to bearings....that would be a trend....I can't know that. Only the warrantee folks would have that data......and as Bob noted, if the "pain" is high, likely they would react, right? The problem for me is when you do repair...ALL you see are the problems! And those are usually a small sampling of the overall set of a given model.

I still want a steel alternative. Again...making "gut" level analysis vs. engineering understanding, but I would like a "Nachi" (for 372's) level option on MY dead saw salvage projects...even if I couldn't prove they are substantially better though my ability to test with the very limited set of saws at my disposal. These are really cool saws and that would be an easy "Modification" to maybe add a little durability..even if its only in my mind. If a more durable bearing was an answer..then the "old" saws needing help wouldn't need a pile of new and expensive upgrade parts.. BTW bearings have performance envelopes too...you usually can get ones in a given size with higher ratings....but when they are proprietary...then the sources therefor options are limited.

 

[Spike60]

LOL To clarify things...I'm a truck & plow driver.. And a farmer...sort of a simple type...

BS, you're one of the smartest people I know. Don't try the farmer defense.

 

[afleetcommand]

agree, but.......5xx serie saws is far more compact.
If we take 346 and 550 as example Husky managed to shave of the crank and they managed to get space for stuffers, impressive by itself, but it may reduse the chance to get rid of heat a tad, that is how I think.

Here is a few crank sizes for those who is interested:
254: 147 mm
357: 144 mm
346: 133 mm
550: 122 mm
242: 127 mm

wow. BTW I love those 254's!! And they have "372" sized 6202's as well! AND there are a lot of them still out there where the bottom ends out lasted the cylinders (wish there were more to build!)......also noted the 242 with a small diameter. Still a lot of those bottom ends out lasted the top ends too.. .Not going to comment on the construction of their bearings. BUT both those saws were awesome and passed the test of time, didn't they, Great saws....where this hobby type is headed for projects in the future..

 

[afleetcommand]

Time for me to shut up now.....

 

[huskihl]

LOL To clarify things...I'm a truck & plow driver.. And a farmer...sort of a simple type...

And as usual, spike60 puts things in context, the voice of both experience and reason....While observations are just that, the size of the "sample" sets do matter....if I see 4 550's to repair and all have bearing issues, that means 100 percent of my experience is colored by that experience. And there may be 100 other repair situations out in the world of that series and I got the only 4 bearings failures! Then my sample wouldn't be the majority in fact it would be the exception not the rule.... But on the other hand of those "100" other repair cases, 50 were related to bearings....that would be a trend....I can't know that. Only the warrantee folks would have that data......and as Bob noted, if the "pain" is high, likely they would react, right? The problem for me is when you do repair...ALL you see are the problems! And those are usually a small sampling of the overall set of a given model.

I still want a steel alternative. Again...making "gut" level analysis vs. engineering understanding, but I would like a "Nachi" (for 372's) level option on MY dead saw salvage projects...even if I couldn't prove they are substantially better though my ability to test with the very limited set of saws at my disposal. These are really cool saws and that would be an easy "Modification" to maybe add a little durability..even if its only in my mind. If a more durable bearing was an answer..then the "old" saws needing help wouldn't need a pile of new and expensive upgrade parts.. BTW bearings have performance envelopes too...you usually can get ones in a given size with higher ratings....but when they are proprietary...then the sources therefor options are limited.

I've always liked your straight forward thinking and (seemingly) never skewed or biased opinions.

 

[Onan18]

BS, you're one of the smartest people I know. Don't try the farmer defense.

Get after him Bob!

 

[Onan18]

Time for me to shut up now.....

Please sir carry on, I always enjoy your insight. As a dealer pretty much all I see in this regard are warranty claims. For some reason (with the loggers around here at least) when these units are out of warranty they never come in for repair. I imagine they get thrown into a "back room" when they fail and a new one gets pressed into service. I would be very interested to know what the common failures are out of warranty.

Joe