562 bearing failure

[Timbercruiser]

Hi everyone. Seems many pulp cutter loggers in my area are having lots of 562 bottom ends go. Does anybody have the solution for the nylon cage bearings ?

[sawguy21]

@Spike60 might have some insights.

[Spike60]

Well a few insites. And the cages aren't the actual problem. Depends on serial numbers, and are we talking fairly new saws or 4 to 5 year old models. There were some bad seals in Apr 20 to Apr 21. I saw it more on 550M2"s. They've made a lot of changes to the bottom ends. Even dropped the compression with a dished piston since mid 22. Apparently they didn't ruin it like the 262/261 deal. 

Other than the run of bad seals, the lower end issues became fairly infrequent over the last few years. The actual seal issue was a bad lip that could simply drop the spring into the works. It was a vendor problem. The POSSIBLE bad seals covered almost a year, but only a small amount were actually bad. There was just no way to know where they went. The 550's I had a problem with were all built the same week. If they were gonna drop, it will happen quick. Saw them go between 7 and 20 hours. After the first 4, I went and replaced them on the rest before sale, and none of them failed. 

One "advantage" of the nylon cage, and I know I'm going to get hammered and who's going to do the hammering, is if it goes, it melts and ends up in the muffler screen. Very obvious when you see it there. And it doesn't take out the top end. On a serious note, I talked to my contact in Sweden about the nylon vs steel thing and there are real advantages to the nylon cage and why Husky and Stihl are both using them. Lab and field testing consistently show this. They've changed an awful lot of stuff on these bottom ends at great cost. They wouldn't leave the nylon bearings in there if they were the problem.

My friend the professor will no doubt join us with a post twice as boring and 3 times as long as this one to refute what I'm saying here. If he was the professor on Gilligan's Island, they would have swam for it.  :
 

[ehp]

From what I have seen and not just the 562 but most saws that cut pulp is the super high rpms limbing and pretty much never having the engine under a full load much during its hours running is super hard on the crank bearings  then add in the factor that lots of guys run not very good 2 stroke oil and at 50-1 and whatever grade of gas they can find its a wonder the saw could last longer than a day or 2 . Plus lots donot clean the saw , I mean I have had pulp saws sent to me that I could not find a fin on the cylinder or the bolt holes thru the cylinder where the 4 bolts go to hold the cylinder to the crankcase . As far as the 562 being not a good saw I would totally disagree with that statement, I got a 562 sitting here in the shop that I would be hard pressed to find another 562 with as many hours on it and living a hard life cutting fairly big hardwood , plus its ported, not just kind of ported . I mean its about as close to full on race saw that can run on 94 octane fuel that I can make and live , It cuts at 13,000 plus rpms in the wood . The only thing I have had problems with it is it will break the clutch , you get about 10 to 12 months and the clutch would break a weight or arm but I'm asking it to do far more than it ever was design for so what I'm saying is if the 562 had a bearing problem I should of had the crank out on this saw a long time ago.  

[weimedog]

My friend the professor will no doubt join us with a post twice as boring and 3 times as long as this one to refute what I'm saying here. If he was the professor on Gilligan's Island, they would have swam for it.  :

See, he obviously doesn't know, that assumption thing .... no way I'm swimming. They all can go and sail that ship patched with nylon. I'll stay on the island with Ginger

BTW to set the record straight. My premise has always been if the service conditions are within design specs, Nylons are fine. When the service condition are outside the design parameters on things like heat , coking on the bearings , and other things, steels will have a better chance of survival. And in the ten years we have argued, I have seen nothing to dissuade me of that premise, in fact I see more to support the "design parameters" premise. Bad bearings from a supplier are going to fail regardless.