Anyone here really know about Stihl chainsaws (larger saws) ???

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Every engine requires back pressure to run correctly

Actually 4 cycle engines needs exhaust velocity to run properly. Too big an opening an you lose scavenging effect for exhaust gases.

 

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Logging was my main occupation for 20 or so years and all of my family were/are loggers. I've used all of the professional saws, Jonsereds, Husky, Stihl, even a Sachs or two. I always used the saw which required the least number of trips to the shop, and that tended to vary year to year. For a while Husky was the saw of choice because we had a very good dealer/mechanic nearby. Then Jonsereds stepped up with some good features and we ran those for a few years. Then a local shop started dealing in Stihl and backed them up with great service and I went with them. I have had great luck with Stihl. In my experience they stand up to long days of wide open throttle better than any of the other brands I have used. With my Husky and Jonsereds I usually ended up doing a top-end job on the engine within a year of purchase, but I never had to do that with any of my Stihl saws. Maybe that is because the power to weight ratio was large enough that I could run a large drive sprocket so I didn't have to lean them out so much to get the cut speed up. Dunno for sure. I still use an 046 and 066 which have many, many hours on them and they still run well. I always use the Stihl bar and chain because they seem to last better for me. This is just my opinion and not necessarily still true as I don't own any new saws. Maybe next year.

One thing that you need to consider is that none of the safety gear like chaps and vests are rated for the big saws. Most safety gear even comes with a "big saw disclaimer". Once you get a chainsaw with nearly 100cc displacement screaming that bit of kevlar won't do much to stop it.

I never had the luck with any smaller cc saws as you describe. They all got used up. The devil is in the details and what constitutes a change in one situation over another are the unspoken details. We leaned our saws out after one day of use no matter what the brand but I'd get 2 years out of the Huskys as well. Everything was shot after that. Also we didn't rebuild anything. We'd take the tired saw in and just get another. Not saying this was the smartest thing to do but we'd just need a running saw that day.
I also had better luck with Sthils chains and bars. I think they use better steel. If they were putting better steel in their engine innards as well, I can see how one might get the benefit of prolonged use. But when you lean an engine out, you make heat and heat is an eventual killer of engines. A hotter engine runs better but it will not last as long.

 

[IgroRockwell]

But when you lean an engine out, you make heat and heat is an eventual killer of engines. A hotter engine runs better but it will not last as long.

Alas, 'tis true, very true. Also, the lube oil is in the fuel and it also is leaned out with a leaner fuel mix. One way to compensate a bit is to increase the oil in the mix. This, in turn makes more smoke. I was always tempted to over-lean my saws in the hot summer months to clean up the exhaust so I wouldn't breathe so much fumes. Of course, this was the very worst time to do so.

 

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Alas, 'tis true, very true. Also, the lube oil is in the fuel and it also is leaned out with a leaner fuel mix. One way to compensate a bit is to increase the oil in the mix. This, in turn makes more smoke. I was always tempted to over-lean my saws in the hot summer months to clean up the exhaust so I wouldn't breathe so much fumes. Of course, this was the very worst time to do so.

I firmly believe IR that there was no greater **** on earth than logging in the summer. To this day I refuse to cut from May through Sept. I say that but I've never layed asphalt in summer. That may be the real Hades.

 

[IgroRockwell]

I firmly believe IR that there was no greater **** on earth than logging in the summer.

I agree. I remember many hot July days, limbing out a big spruce or hemlock, no breeze, the blue fumes hanging thick in the greengrowth, salt sweat running in my eyes, choking on fumes, hurrying to get the tree limbed so I could step away and take a deep breath of clean air.

 

[turnkey4099]

Every engine requires back pressure to run correctly

Every 2cycle does. I dont' think 4cycle needs or even wants any back pressure. As for that loud modded Stihl - it was so loud that If I was within 50 ft doing something I had to put on my headsets. Dunno how it could even run with that much "modding".

Harry K

 

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Every 2cycle does. I dont' think 4cycle needs or even wants any back pressure.
Harry K

You'd be dead on correct with that Harry. Back pressure needed for auto engines is a myth perpetrated by the guy who put 3 " exhausts on his Honda civic and wondered why the car would go no where. He then figured that he was flowing too freely and needed some residual pressure (back pressure) to build up compression as 2 cycles do. Thus the story of all engines needing back pressure resounded throughout the kingdom. Engine exhaust beyond 2 cycles need velocity. The guy in the Civic reduced his velocity thus his scavenging effect and just made no power for his engine rpms. Now if his little motor could rev to over 12,000 rpms, he might have seen a performance gain after 6000 rpm and just keep building power after that. It is why even TF/D dragsters need 2 .75 inch "zoomie headers" rather just dumping exhaust straight from the port as the headers provide velocity of exhaust.

 

[Grumpy Old Man]

You'd be dead on correct with that Harry. Back pressure needed for auto engines is a myth perpetrated by the guy who put 3 " exhausts on his Honda civic and wondered why the car would go no where. He then figured that he was flowing too freely and needed some residual pressure (back pressure) to build up compression as 2 cycles do. Thus the story of all engines needing back pressure resounded throughout the kingdom. Engine exhaust beyond 1 pulse need velocity. The guy in the Civic reduced his velocity thus his scavenging effect and just made no power for his engine rpms. Now if his little motor could rev to over 12,000 rpms, he might have seen a performance gain after 6000 rpm.

Back pressure helps with valve cooling and if you remove back pressure you'll cook the heads , take the stock exhaust off a harley and put straight pipes on it and you have to add torque cones into the exhaust tubes or it won't run worth sh*t , on a car all you need to do is increase fuel your really dealing with velocity and the small amount of reduced pressure when the valve is closed would help clear the exhaust gases when it opens , if you take away some sort of exhaust you lose velocity and thats why your civic didn't get any benefit

 

[IgroRockwell]

Been using chainsaws all of my life and never did any kind of "muffler mod". Occasionally a muffler would loosen or fall off and I would put it back on. When you have to hear a screaming saw hour after hour, day after day you tend not to do anything to make them any louder. At least I didn't, nor do I remember any professional loggers doing so. My advice would be to get a saw of the right size and learn to sharpen it well and maintain the bar. As long as the saw is running well, sharpening the chain properly and keeping the rakers at the proper height is, in my opinion, the most important consideration in saw performance. The difference between avarage chainsaw men and good ones is in bar/chain maintenance skills. My opinion.

 

[Grumpy Old Man]

Been using chainsaws all of my life and never did any kind of "muffler mod". Occasionally a muffler would loosen or fall off and I would put it back on. When you have to hear a screaming saw hour after hour, day after day you tend not to do anything to make them any louder. At least I didn't, nor do I remember any professional loggers doing so. My advice would be to get a saw of the right size and learn to sharpen it well and maintain the bar. As long as the saw is running well, sharpening the chain properly and keeping the rakers at the proper height is, in my opinion, the most important consideration in saw performance. The difference between avarage chainsaw men and good ones is in bar/chain maintenance skills. My opinion.

I never had the need to chop up a good running saw .