wyk
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Everything posted by wyk
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Mitch is here to help: [ame=http://www.youtube.com/watch?v=29FiGmDQkaM]How to tune a chainsaw - YouTube[/ame]
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In order for the two stroke oil to not ignite at all, the chamber temperatures and pressures would have to be so low as to not completely burn the petrol as well. The pressure alone from the petrol igniting would ignite most oils, let alone the fact there is fire and spark and heat in there beforehand. The amount of unburnt fuel and oil pouring out of the exhaust at that point would simply be ridiculous. Revisiting the 32:1 statement I made earlier. As I mentioned before regarding those mixtures - remember that many of the old school saws that asked for 32:1 or 25:1 had factory compressions in the 180-200psi range as well. I had an old McCulloch 7-10 that you could hold up by the starter handle and it would never unspool it. That thing had a ridiculous amount of torque. With a 20" bar on that 7-10, it was nearly impossible to stall it in the cut with a sharp chain.
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You can get good semi synthetic 2 stroke oil suited specifically for chainsaw use. I use a semi synth at 40:1 in my ported saws here, and at 43:1 in the US(easier to mix it by the US Gallon with the little jugs ya get). I get a good burn, few deposits, and easy to tune and mix. And it's also very affordable. Bear in mind that many hobbyist and builders running their saws at 32:1 have much higher than usual stock compression, some advance the ignition, and all should have mirror polishes on their exhaust ports. I found this article interesting reading: How 2 cycle aircraft engine oil works, what makes a good 2 stroke oil, two stroke air cooled engine oil, two stroke liquid cooled engine oil.
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BTW, just so we're clear. If you run your saw at 32:1 with synthetic - you will cake up your exhaust eventually. The manufacturers actually know what they are doing. Most, if not all synthetics, are meant to be run at 50:1 in an air cooled two stroke. The detergents, agents, and ash formulations are set up for a specific application. I would not go using random oils at random ratios for a specific task; chainsaws, in this case. A chainsaw is stopped and started and lashed about often, and all day long. Using an oil designed for race bikes, to be used at a constant high RPM with oil cooling or water for extended run times won't necessarily work well in a chainsaw that stops and starts and heat cycles like mad.
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Never apologise! If yer not getting dirty, yer not a man. Or, er, sumfin.
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In order for this to be true, the combustion chamber temperature in a modern two stroke would have to be below that required to ignite some of the petrol being used. Lets face it - the oil burns. It combusts. It ignites - as it would. It's basically a different form of petrol. It's not sludge in there, folks - it's two stroke oil. I have seen 'stock appearing' class race saws keep increasing their cutting times up to 32:1 ratios with fully synthetic oil without leaning. Some of the oil burns, some of it stays in the pan, some of it sticks to the rings and helps lubricate and increase compression.
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Those glasses are dirtier than that clip
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MS 241 C-M - Compact professional chain saw with M-Tronic
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Some cylinder kits come with the adapter.
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McCulloch made good saws up untl the EPA and some management issues killed them in the 90's(when they basically rebadged other makes saws to try an comply). My 800 easily pulled a 32" bar in softwoods.
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Oil has more BTU than petrol. The exhaust is blue because the oil combusted. Even 4 stroke engine oil would combust in the heat of a 2 stroke chamber, let alone 2 stroke oil. How clean it burns is another debate altogether. But it does burn. This is what attracted the attention of the EPA, afterall. As for rich or lean - you tune your saw for the fuel that is in it. The ratio is moot if you know how to tune the saw.
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I think he smokes.
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For all we know, that may be what he's trying to prevent with the pull cord.
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Maybe. But it does mean he's forgotten more about how to use and repair a chainsaw than any of us ever knew. Unlike my first response, this one isn't a joke. The guy knows his stuff, and he's not messing around.
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He put the 'saw' in chainsaw?
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He has a reason for it on one of his vids. I dunno bout questioning the saw 'king' - he's been repairing saws and porting and making race saws since 1960 or so... he might smite you.
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[ame=http://www.youtube.com/watch?v=KfWbXkIyOMo]The chainsaw guy shop talk Stihl 090 G Chainsaw Vintage - YouTube[/ame]
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Run your saw very rich, regardless of mixture, on a nice cold day and watch all the blue smoke that comes out of it - some of that oil does make it to the combustion chamber.
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hrc54 is harder than the drive links on chainsaw chains.
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Hah! In other words, it may well be 6160 steel. Good luck with that.
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Almost forgot to add - D2 tool steel is usually HRC61-62 or so... It also is a high speed steel - so it retains that hardness well above 400*C, which is about the temp a grinder may get out of it. It has a buttload of carbon in it - 1.5% - roughly 10X more than 1109 steel. So, if you use a d2 drill bit, it will eventually heat up that 1109 to where it will definitely be lower hardness than the D2... assuming your equipment likes that sorta heat... er...
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1109 is an odd one, but can be hardened to 60HRC if I read this data sheet right. It is basically considered an industrial steel for bars and tubes, structural stuff as well. It doesn't have enough carbon to hold an edge well for knives. But it has enough to harden well. It would be widely available to any manufacturer, and dirt cheap. Most chainsaw bars are made from Molybdenum steel - it has all the properties you need in a bar, is very strong for it's weight, and is used extensively in the auto industry = widely available, cheap and easy to make. I have heard from a mechanical engineer that Stihl's bars are likely made of 6100 series steel. Lorrie sprigns are made of 6160 steel. So this would also be widely available and affordable in large stock. The added vanadium in 6160 vs 5160 allows it to harden a bit more than 5160 and adds even more shock resistance. I am told it is a great steel for swords.
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How 'bout? - OREGON® Hand Held Chain Saw Replacement Parts (BTW, tried to order stuff the other day and it just would hang at check out when I tried to use paypal)
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Forgot to add, I thought all the new dollies were basically d009 and k095 mounts.
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Cheers! It's 7mm thick at the guard, but is very light and quick in the hand. Bowie knives were basically derived from old Sheffield butcher's knives.
