Stihl MS500i cylinder and piston

[Moparmyway]

 

[Moparmyway]

 

[Moparmyway]

 

[Moparmyway]

 

[Moparmyway]

Do you have to reset the saw when adding the bark box, or does it automatically retune ? ..

It automatically tunes itself. There is no choke or cold start lever.

 

[Moparmyway]

Here’s where I’m at with my observations of this saw and the mix that it’s been used with:

1. surprisingly, I see oil in the bottom end and on the piston.

2. the exhaust side of the piston is pure carbon scoring, including the stuck rings.

3. no 4 corner scoring evidence here

4. the intake score on the piston matches up with a witness mark in the chamferr area of the port


I believe that the mixture used is soley responsible for the carbon on the top of the piston and the carbon scoring of the exhaust side of the piston and cylinder. I can say that the intake had something foreign rubbing there at one time, but not now, as there isn’t anything there now that would cause this

The oil lubricates good, but excess carbon is forming in the combustion area and is damaging the machine

 

[Nutball]

Here’s where I’m at with my observations of this saw and the mix that it’s been used with:

1. surprisingly, I see oil in the bottom end and on the piston.

Could be from all the effort put into trying to start it after it broke. That would fog a bottom end real good with oil.

Looks like it got hot to me, but I have little experience with the look of different scoring and its different causes.

Do they stop to sharpen the chain, or just keep at it?

 

[Moparmyway]

I might agree with you, and it’s possible that some extra oil is in the saw from trying to start it, however the bottom end of the saw shows that it’s been getting enough lube and staying cool. I’ve also seen little oil in the mix score more of the piston and discolor the big end bearing of the rod, along with cooking the bottom of the piston, under the crown. Thats definitely not the case here.

 

[Moparmyway]

I’m pretty sure that we are just looking at a new piston & rings, the cylinder should clean up and we’ll see how she spins on the lathe

BUT

Id definitely recommend that a different oil be used. My top 3 are Dominator, Schaffers 7000, & Red Armor

You’d be better off running pump gas while a better oil

 

[TINYHULK]

We ran stihl orange bottles since I’ve been in the company about 8 months at least. The last month we ran stihl grey bottles. After all of this I changed to red armor cause I’m familiar with it from landscaping and I have a local echo dealer that gives me a good price. We always ran 50:1. It was about 3 months ago I learned about running a full chain can cause excess heat in the crank case and began to teach my guys about the dangers of running a dull saw so we stopped that (as much as I could make them). When someone isn’t good with sharpening it seems they would rather force a dull chain then sharpen it and end up being discouraged at their work even more. What would be the danger of running a lower octane gas? Could that be a factor? I’m a hawk for the proper mixture but I think they may have been pumping regular 87 octane in the saw jugs

 

[Maintenance Chief]

I literally saw the pictures in the "muffler mod" thread and thought , oh they're killing saws with dull chains!
Besides mix ratio mishaps dull chains end more chainsaws then probably skidders ( maybe tied according to my shop) .
The super fine particles clinging under every surface is a good indicator of a saw that sees a dull chain daily .
I know getting people to sharpen after a dirt or rock ( foriegn object) event can be difficult, but even if out of an 8 hour day their running dull chains 2 hours it is absolutely going to ruin that saw.
I not only teach this in class I make people cut with their chains , then cut with mine and ask " whose gonna work harder ?"
Hell have 4-6 spare chains for each saw to change out, its a sh¡t load cheaper than 500i's . If the guys or gals aren't afraid of being cut from the chain handling it bare handed it's not sharp.

 

[huskihl]

Take the dogs off the bucking saws and teach them to make chains that cut on their own. When they master that, put the dogs back on.

The first initial smear may have had some thing to do with the switch from orange to gray bottle oil, but most of that is from just not enough lubricant or fuel to cool it down from running dull chains it looks like to me. I’d still be mixing the red armor at 40 to 1 just to be safe

 

[farminkarman]

Best answer material right here:

Take the dogs off the bucking saws and teach them to make chains that cut on their own. When they master that, put the dogs back on.

 

[Moparmyway]

Take the dogs off the bucking saws and teach them to make chains that cut on their own. When they master that, put the dogs back on.

The first initial smear may have had some thing to do with the switch from orange to gray bottle oil, but most of that is from just not enough lubricant or fuel to cool it down from running dull chains it looks like to me. I’d still be mixing the red armor at 40 to 1 just to be safe

I’m not sure that I’m where you’re at right now Kev, the bottom end looks real good. The oil I’m seeing is probably from trying to start it, so even if I wipe off all of the oil, this saw has been running cool enough to keep the bottom end looking nice. Either Homer Simpson ran the last tank or two with a dull chain, or the switch to the different oil is causing the carbon scoring. I’ve seen my 500i banging on the limiter while cutting a stump, went through a bunch of rocks and water, Dominator at 25:1 and she still looks brand new, no matter how dull the chain or operator

One thing is for certain, Red Armor @ 40:1 will help regardless if it’s Homer running dull chains or carbon puking. The other thing that I’d suggest would be that @TINYHULK only run semichisel chain on the saws over 50cc. You can still load a saw and cut with it as the chain dulls


I know guys that run 87 all day long, it’s definitely in need of a little more oil and a little less carbon

 

[Nutball]

I’ve seen my 500i banging on the limiter while cutting a stump, went through a bunch of rocks and water,

Banging the limiter may have helped. The dummies running it dull may have leaned so hard as to heavily load the engine.

Maybe the 500i has better crankcase cooling? A hole in the flywheel area for that purpose? The thingy sticking up under the piston could get cooled by the fresh charge.

I have heard some detonation in a stock 2188 on 87 octane, but it went away and gained a smidge of torque on 93. My personal preference would be to use premium gas in the saws, especially if it gets a compression boost. It makes me feel safer.

 

[Moparmyway]

My personal preference would be to use premium gas in the saws, especially if it gets a compression boost. It makes me feel safer.

Point is that there aren’t any signs of detonation and that this saw can run 87 as equipped from the factory

 

[TINYHULK]

Since these 500i fiascos I have became much more strict about these saws and standards of use. I know one guy I really have to get on about running dull saws and he was the one running it the day before it wouldn’t start for me. He gets so in his feelings he will sit there and fight with the saw versus getting up and putting proper work in on sharpening the chain. Any tips on training newbies on sharpening?

 

[woodfarmer]

So from what I’ve read, Dominator oil is only recommended in high performance racing engines that produce high amounts of heat. The additives won’t fully burn and actually will leave carbon deposits.
Interceptor oil is recommended… at least if your into spending $20 a pint on oil mix.

 

[huskihl]

So from what I’ve read, Dominator oil is only recommended in high performance racing engines that produce high amounts of heat. The additives won’t fully burn and actually will leave carbon deposits.
Interceptor oil is recommended… at least if your into spending $20 a pint on oil mix.

Dominator actually works really well in a saw. I’ve been running it at 32:1 now for a couple years and there’s very little carbon on the piston and none in the exhaust port

 

[Nutball]

So from what I’ve read, Dominator oil is only recommended in high performance racing engines that produce high amounts of heat. The additives won’t fully burn and actually will leave carbon deposits.
Interceptor oil is recommended… at least if your into spending $20 a pint on oil mix.

Chainsaws produce high amounts of heat.