540/8800 Piston/Cylinder History
Dec 17, 2021 10:40:49 GMT -5
onlyhomelites, undee70ss, and 3 more like this
Post by lesorubcheek on Dec 17, 2021 10:40:49 GMT -5
There's been lots of discussions in the past regarding why Homelite changed the 540's thin ring piston and cylinder to the 8800's design. Many people have reports that it was due to overheating, and that's been the accepted answer. A few days ago on a Homelite group on fakebook, an individual shed a whole new light on this topic. I won't name him, since he may not want that, but hopefully he'll come over here and share even more of his knowledge of history on these saws. Heck, he may even be a member here already. I just know that when I read this, it really made sense and wanted to share what he said. And, I believe every word since he was a regional service manager for Homelite. I won't quote his post verbatim but will try to summarize.
Previous field service individuals told stories about how one 540 would be bulletproof and yet the very next serial number unit would blow up. To solve the problem, engineering took the shotgun blast approach by changing to the thick ringed piston and also mods to the cylinder, instead of trying to pinpoint the root cause for 540 failures. Soon after the 8800 design changeover took place, a worker-bee on the assembly line spoke up and said "why did you change all this stuff and not fix the alignment pin issue on the crankcase halves?".
So, I'll be a .... that just makes perfect sense. If the case halves didn't align, the cylinder deck would have a gap and the base gasket was very thin on these. Air leak would develop and there's another bad saw.
Still questions remain though. If the 8800s had the same crankcase alignment problems, how many of them also developed an air leak? Maybe the leak was so insignificant and the thin rings on the 540 just happened to push past the limit. Maybe the pin alignment problem was beyond control of the in-house engineering team since pretty sure Lunt produced the castings, and maybe they just did whatever was available to try to band-aid the problem. The market was very competitive with Husqvarna and stihl coming on strong, so maybe they just reacted in the only way they could to try to hope the saw wouldn't get a bad name. The changeover from the plastic to magnesium rear handle was likely based on another failure or quality incident. It'd be great to learn the details on that one.
Anyways, stills lots of unknowns, but this little tidbit of information makes good sense of at least one aspect of this series of saws.
Dan
Previous field service individuals told stories about how one 540 would be bulletproof and yet the very next serial number unit would blow up. To solve the problem, engineering took the shotgun blast approach by changing to the thick ringed piston and also mods to the cylinder, instead of trying to pinpoint the root cause for 540 failures. Soon after the 8800 design changeover took place, a worker-bee on the assembly line spoke up and said "why did you change all this stuff and not fix the alignment pin issue on the crankcase halves?".
So, I'll be a .... that just makes perfect sense. If the case halves didn't align, the cylinder deck would have a gap and the base gasket was very thin on these. Air leak would develop and there's another bad saw.
Still questions remain though. If the 8800s had the same crankcase alignment problems, how many of them also developed an air leak? Maybe the leak was so insignificant and the thin rings on the 540 just happened to push past the limit. Maybe the pin alignment problem was beyond control of the in-house engineering team since pretty sure Lunt produced the castings, and maybe they just did whatever was available to try to band-aid the problem. The market was very competitive with Husqvarna and stihl coming on strong, so maybe they just reacted in the only way they could to try to hope the saw wouldn't get a bad name. The changeover from the plastic to magnesium rear handle was likely based on another failure or quality incident. It'd be great to learn the details on that one.
Anyways, stills lots of unknowns, but this little tidbit of information makes good sense of at least one aspect of this series of saws.
Dan
