What year did saw performance and quality really start to go downhill ?
- Thread starter bigv
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I would say that saw performance and quality really started to go downhill for Poulan, Jonsered and Partner happened the day that they were bought by Electrolux.
MechanicMatt
Cut Split Stack Burn
I miss mr. Stumpy
Locust Cutter
Sawing for Sanity
Me too.
You don't always have to weld up a popup piston. Diamond and Wiseco used to do runs of 2 cycle pistons and they'd keep the one-off's that didn't make the QC cut. I'd buy those via the same guy I got my Harley and Mopar pistons from.
You get a piston with tall enough compression height to begin with and you can sculpt a dome by turning it down. The biggest thing is getting a slug that has the pin placement you want. You have more options this way, you can induce a crown in center, or you can leave the area around the skirts built up and have a relief in the middle like was done for flame travel ala Hemi style piston.
If you've already got a piston that you can use, there is nothing wrong with welding them. You have to accept the limitations, though- you're changing the grain and structure of that piston. It's important what filler you use- I've used 4047 high silicon for a lot of the little pistons. You kind of take a guess if you've got a junk piston and cut it down the center.
If you have a surface grinder or a large enough and rigid enough mill with accurate work holding you can TRY to adjust squish by machining both halves, but most people I've seen go that route don't consider what that does to flywheel clearance and how the bearings seat into the cases. Granted, you're not removing much in most cases, but it can loosen things up. Loctite 609 can cure it, but if your fixture isn't rigid, nothing cures caddywampus.
You can port anything- porting doesn't just mean knocking the intake and exhaust sides wide open and calling it day. You have to pick and choose your battles as to how you adjust the port timing and how you optimize it. You can have a clam shell that will produce ridiculous high speed RPM's and power right up to the point where the whole thing grenades on you. That was never the point to me. The point was taking what I had at the time and making it more usable and getting more power and experimenting and learning. So yeah, you can open up ports on clamshell and adjust your CH to compensate and you get a more effect air pump over the operating RPM range.
There was an old machinist named Ballew in Blue Ridge GA who showed me how he'd leave a relief in center- he liked weird stuff. He had a Poulan that was built by Dolmar that he did that to, and he had added a dual plug to it- it was just an oddity for fun- it ran well and it was really something to see. He had a forge over around Westminster South Carolina do crazy stuff for him back when they were open. He had a Slant Six that he had a head cast for on spec, and had the block coated- made it into a steam engine. The boiler was in the bed.
He had a couple books that were about 2 Cycle Kart engines from either the 50's or 60's and those was the best written treatise on 2 cycle performance I've ever seen, other than the Porting Threads done here. One book described had tuned rams horns intakes on some of the twin 2 cycle kart engines, and they discussed the theory of the runner length and height for a single runner intake for some of the "big" McCullough kart engines.
You get a piston with tall enough compression height to begin with and you can sculpt a dome by turning it down. The biggest thing is getting a slug that has the pin placement you want. You have more options this way, you can induce a crown in center, or you can leave the area around the skirts built up and have a relief in the middle like was done for flame travel ala Hemi style piston.
If you've already got a piston that you can use, there is nothing wrong with welding them. You have to accept the limitations, though- you're changing the grain and structure of that piston. It's important what filler you use- I've used 4047 high silicon for a lot of the little pistons. You kind of take a guess if you've got a junk piston and cut it down the center.
If you have a surface grinder or a large enough and rigid enough mill with accurate work holding you can TRY to adjust squish by machining both halves, but most people I've seen go that route don't consider what that does to flywheel clearance and how the bearings seat into the cases. Granted, you're not removing much in most cases, but it can loosen things up. Loctite 609 can cure it, but if your fixture isn't rigid, nothing cures caddywampus.
You can port anything- porting doesn't just mean knocking the intake and exhaust sides wide open and calling it day. You have to pick and choose your battles as to how you adjust the port timing and how you optimize it. You can have a clam shell that will produce ridiculous high speed RPM's and power right up to the point where the whole thing grenades on you. That was never the point to me. The point was taking what I had at the time and making it more usable and getting more power and experimenting and learning. So yeah, you can open up ports on clamshell and adjust your CH to compensate and you get a more effect air pump over the operating RPM range.
There was an old machinist named Ballew in Blue Ridge GA who showed me how he'd leave a relief in center- he liked weird stuff. He had a Poulan that was built by Dolmar that he did that to, and he had added a dual plug to it- it was just an oddity for fun- it ran well and it was really something to see. He had a forge over around Westminster South Carolina do crazy stuff for him back when they were open. He had a Slant Six that he had a head cast for on spec, and had the block coated- made it into a steam engine. The boiler was in the bed.
He had a couple books that were about 2 Cycle Kart engines from either the 50's or 60's and those was the best written treatise on 2 cycle performance I've ever seen, other than the Porting Threads done here. One book described had tuned rams horns intakes on some of the twin 2 cycle kart engines, and they discussed the theory of the runner length and height for a single runner intake for some of the "big" McCullough kart engines.
So many knowledgeable people got run off from here over the last 3-4 years. 
And anyone is welcome to call BS on anything I write- I just don't see the point in arguing over the Internet. I could very easily be a bored 80 year old woman from Scranton typing up whatever comes into mind in between the nurses turning on my morphine drip. And the people wanting to argue with me may well be Pomeranians, Great Pyrenees, or German Shepherds.
