Tzed250
Addicted to ArboristSite
Count me in as too lazy to take out the plug....
Oops, broke through top of piston on Stihl MS 180 CB-E
- Thread starter phred45
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timberwolf
Addicted to ArboristSite
Actually I think peek cyl pressure is generally well before maximum mechanical advantage, but it becomes a calculus problem in getting the most area under the curve.
Also need to considder the flame speed, It is possible to have the piston actually running away from the expanding charge. From what I have read on it, if part of the fuel (2 stroke gas, not 4 stroke or deisel injection) is not burning by 20 deg ATDC at full operating RPM it really will not get the chance to transfer much energy to the crank. This is in part due to the piston moving away from the expanding charge at an increasing rate.
Gets into some complicated stuff, squish velocity, charge configuration, fuel burn period, flame speed, endgass conbustion, and the interplay between compression and ignition timing. I don't even think the consumer engine softwares really do a good job when it gets to that level.
Get off you're high horse.
Anyway I use an impact as well, no need to remove the flywheel. It does seem like the 170/180's are made out of paper IMHO.
timberwolf
Addicted to ArboristSite
That a 2 stroke spec that could relate to a saw or from automotive?
Wow, this is way more input than I'm able to digest right now. I'm still somewhat of a newbie with chainsaws.
Just ordered the right piston stop from the Stihl dealer. Still have to take the engine apart more to look at the rod, let's hope it's not bent.
The reason for the 25:1 was that I told my wife the wrong gas can and she used the milling gas for her little 180. We usually ran 40:1 because my Poulan runs better on it and we used the same mix for both saws. Would the 50:1 per manufacturer be better?
Somebody mentioned that he runs only synthetic oil in his mix would that be the same as I run in my car? I know they sell specific synthetic for saws but I don't know what the differenceis or if there is one.
Just ordered the right piston stop from the Stihl dealer. Still have to take the engine apart more to look at the rod, let's hope it's not bent.
The reason for the 25:1 was that I told my wife the wrong gas can and she used the milling gas for her little 180. We usually ran 40:1 because my Poulan runs better on it and we used the same mix for both saws. Would the 50:1 per manufacturer be better?
Somebody mentioned that he runs only synthetic oil in his mix would that be the same as I run in my car? I know they sell specific synthetic for saws but I don't know what the differenceis or if there is one.
What is with you? You cop these attitudes out of the blue? You had a problem with it when I didn't go by the book and broke the saw, and now that I'm promoting doing it by the book, you still have a problem with it:bang: All I'm saying is that I won't use any other method than Stihl recommends on these little saws.
People always seem to forget that the oil in 2 cycle mix burns with the fuel. Sure it changes the air fuel ratio, but how much and in what way is over my head, but simply thinking it's linear is incorrect.
With that said 25:1 is too much with good oil. I run 32:1 in every saw I own without any issues.
Tzed250
Addicted to ArboristSite
No attitude whatsoever. You said the piston needed to be near TDC. That is a mistake. I have a problem with misinformation. Do you see me say something to you when your facts are straight???
What leaves the piston closest to TDC, a typical stuffing of rope, or a plastic piston stop may 1/4" thick?
Tzed250
Addicted to ArboristSite
Define "typical stuffing of rope" please.
My OEM Stihl piston stop is much thicker than .25"
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mowoodchopper
Polar Bear
Right there's another reason to only use the right tool. No way to know you have it where it should be.
Tzed250
Addicted to ArboristSite
Agreed.
My use of the impact is not "using the right tool", but my experience with it has shown it to be a viable method for clutch and flywheel removal. I will probably break the next saw I use it on....
Andyshine, do you use the 32:1 also for milling? I have the Stihl 076 and used the 25:1 because it was suggested on the milling forum.
Yes with a good syn oil 32:1 is more than enough oil for milling and the 076. Make sure to tune the saw rich when milling, this goes for any saw with any oil ratio.
Yes with a good syn oil 32:1 is more than enough oil for milling and the 076. Make sure to tune the saw rich when milling, this goes for any saw with any oil ratio.
What synthetic can I use? Do I have to use the oil they sell for saws or can I use the full synthetic for cars? The 076 uses a lot of oil and gas. Wished I could find a cheaper bar oil too.
