Cooked two MS660s in two days!

[OneWithWood]

Some days it doesn't pay to get out of bed...

I purchased a new MS660 to use with a Grandberg mini mill to split some large red oak logs for milling.  The log I started on is 38" in diameter and has sat in a yard since April.  I fastened my guide rail to the top and proceeded to rip it down the middle with my MS460 equiped with a 32" bar and ripping chain.  I got halfway throught the log before the saw got hot and quit.  The cylinder was scored.  I assumed I was just asking too much out of the 460.  Well the new 660 with the same bar and chain lasted about 10 minutes before it suffered a similar fate.  The new saw still had the fuel and synthetic oil from the dealer in it so I know it was not fuel related.  I took it back to the dealer who determined it must have had a bad seal from the factory and ordered another saw under the warranty.
I got a little further with the replacement.  I put on a 38" bar with RMC chain and cut a number of cookies of an equally large log then put the 32" bar with ripping chain on it and proceeded to finish ripping the first log.  I finished up the first cut, rolled it over, affixed the rail guide and got half way through the length of the log before the saw suddenly heated up and quit.  Yup, scored that piston and cylinder too.   

I took it back to the dealer.  This dealer is a real gem, being very patient and working with me to sort this out.  I explained what I was doing and what happened.  Neither he nor I could come up with a reason for the saw failures.  I wondered if milling full out in a vertical position was somehow causing the saw to lean out.  The dealer said it should not matter.  He is contacting the Stihl rep who I hope will come out with another saw so I can demonstrate what I am doing.  Something is definately not right and I need to get it figured out.   

Any ideas?

[wannabeonetoo]

Maybe the new "Chinese" P&Cs Stihl is using aren't what they're cracked up to be ?

Just kidding............. (I hope!). 
Sounds as though you have a great dealer ! When will the rep. be around ?

Steve

[Buck]

You definitely have an above average dealer.

[ladylake]

 Give those saws more fuel for milling.    Steve

[John Mc]

A lot of saws come set pretty lean from the factory. Did you (or your dealer) richen it up a bit? Ripping is a tough application for a saw. A little richer mixture helps it run a bit cooler. I don't know the 660... maybe it's one of the automatic adjusting mixtures?

Also, I wonder if you should run a few tanks of fuel through the saw in a less demanding application before jumping right in to ripping? Just asking here... one of our resident experts would know better than I.

John Mc

[lumberjack48]

 Trying to pull or push the saw just a little to fast in to a green [ wet] Red Oak. You can tell by the sound of the saw how hard its pulling, and if its pulling to hard to long it can't get rid of the heat fast enough, it will score the piston on the port side every time.

I hope they come out and run the saw it will be interesting, keep us in formed on this matter.

[zopi]

Hadda 660 do the same thing...just sawing....having it fixed now, gonna richen it up a bit....stihl is beginni.g to annoy me.

[Collima]

I run the stihl 880 with a 72" bar for ripping logs. I built my own Alaskan mill. I make a lot of wide live edge slabs.  Used to use ripping chain, but went back to .404 chisel chain cause it's cheaper, easier to sharpen, and cuts good.  Make sure you have an oiler on both ends of the bar!  Crank the oiler all the way up on your saw too.  Mix your fuel nice and rich.  Keep the rpm's up.  If your saw starts bogging down pull 'er back a bit. Other than that your saw should be able to handle it.  Either your doing something wrong or the saws you got were defective. It should be able to do the job!
By the way, I need a dealer like yours!!

[Old Iron nut]

You might try using a heavier 2 cycle oil to gas mix in the saw. I fried a P51 Pioneer saw several years ago using Amsoil's 100 to 2 cycle oil. That stuff does not work in 2 cycle engines running 8500 rpm. Amsoil did not stand behind their product, said there was alcohol in the gas. We did not have alcohol or ethanol in our gas at that time. I finished the remaining 3-4 gals. that I had mixed up in a Lawn Boy mower. That thing never ran better. I am presently using a 16 to one mix in 100 octane av gas in my P41 and P52 Pioneer saws and have not had any trouble. Things run very well, don't have to pull the starter cord 20 or 30 times to get them going. At the time I fried the P51 the weather was very hot. This may have some bearing on your saws failing. I would question using synthetic 2 cycle oil in chainsaws. I am a firm believer in synthetic oil. Use it in everything here, including tractors. Hope you get your problem solved, man can't afford too many incidents like that.  Needless to say, I will never use any Amsoil product again.

[John Mc]

Amsoil is actually a pretty good product... I just wouldn't run it at 100:1 as they advertise. Maybe I'd take a gamble in a weed-whacker, but not in a high-end chainsaw.

[clww]

I've never run a 660, but when I am ripping with my 084 or 090, I mix at 32:1.

[shelbycharger400]

i have done some free hand ripping to break down some large logs in 24in dia.  using 40 to 1, with quaker state 2 cycle  (comes out of the can like syrup)  the older craftsman definately gets hot  at wide open (10-12000 rpm), but usually i back off a bit,  and let it run at idle or a little off idle  to cool down a bit

[quietrangr]

I run Amsoil Professional 100 at 70 to 1 and have had very good luck with it for about four years, cutting about four or five tanks a day. For ripping I'd make sure you're not revving too high, and richen up your oil to gas mixture, maybe try it at 32 to one, and break in a new saw on firewood or something less steady high demand than milling.

[Ironwood]

I just wanna subscribe to the thread.

Ironwood

[Weekend_Sawyer]

 Yea, me too, I was just wondering today if anyone else replied to messages just be able to get notified of updates.

Jon

[lumberjack48]

 The Stihl Dealer told me to never run my Stihl's leaner then 32:1, never run a off brand oil, and absolutely no ethanol.
 He knew how hard i worked a saw, i don't mean beat on them, i took top care of my saws every night, i blew them out, they got the full treatment, because in the morning it was off to the battle again, full throttle, i always set goals, and a battle plan, i couldn't have saws or a man lagging behind.
   

[John Mc]

 Yea, me too, I was just wondering today if anyone else replied to messages just be able to get notified of updates.

All you have to do is click on the "Notify" button near the top right of the thread.

[Weekend_Sawyer]

 True John, but this way I am part of the conversation. 

[Al_Smith]

  Well I'm not going to get into oil mix ratios because everybody wants to argue how much and what kind so run what you want to .

However if you are ripping ,milling whatever keep in mind that aside from stumping this is about a demanding of a task ever placed on a chainsaw .As such you have to run a rich carb setting .Lean fuel mix will run much hotter than rich .Too lean or even with a normal setting for average usage will not work out well on long rip cuts .

Then too in my opinion for the two cents it's worth seems to me that many have the bright idea they must cut lumber as smooth as if were ran through a table saw with a hollow ground cabinet blade so they use rip chain .Rip chains are slow,they pull saw dust instead of chips .To me they put undo stress on the saw where a standard old chisel will cut smooth enough for the purpose .After all if it is finish lumber it will be planed anyway .

[lumberjack48]

Can't say it any better then that AL