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Hole in top of 039 piston

Started by hms11, December 04, 2019, 07:42:12 PM

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hms11

Hey everyone,
Just in the process of putting a fresh plug, air filter and doing a muffler mod on my 039 and I was looking at the piston top and noticed a small hole near the center. It almost looks.... drilled? I realize it isn't a drill holes, but what's everyone's thoughts? Saw ran fine when I decided to give it a tune up. 


 

sawguy21

Poor oil/overly heavy mix is my guess. The spark plug is igniting the built up carbon.
old age and treachery will always overcome youth and enthusiasm

donbj

sawguy21, I appreciate your posts on here. Lots of good knowledge
I may be skinny but I'm a Husky guy

Woodmizer LT40HDG24. John Deere 5300 4WD with Loader/Forks. Husky 262xp. Jonsered 2065, Husky 65, Husky 44, Husky 181XP, Husky 2100CD, Husky 185CD

sawguy21

old age and treachery will always overcome youth and enthusiasm

hms11

Sawguy21, thanks for the info, you've been super helpful on both my posts so far.

In your opinion..... should I be putting a new piston in? Saw ran fine, I've personally only ever used Stihl oil in it and usually mix at roughly 40:1 because 50:1 always seems so....... sketchy to me. Maybe I've caused my own problem running too oil-rich but I see lots of guys saying they run 32:1 in here? Is this destruction waiting to happen or could this saw run for years like that? Or is this more of a coin toss type of situation where I *might* be good for years, or it might grenade tomorrow?

Thanks!

sawguy21

You definitely need a new piston. Something is wrong here. It should not be carboned up like that at 40:1 with Stihl oil. The crown should be at most a dark brown with a thin coating of carbon. Are you in the habit of cutting at low rpm's?
old age and treachery will always overcome youth and enthusiasm

Air Lad

Is the correct plug being used ?
Was given a Stihl fs44 whipper snipper that had carbon buildup like that
The guy used 2 year old go kart racing fuel that had a lot of castor oil in it
It cleaned up ok but needed a strip down

donbj

Quote from: sawguy21 on December 05, 2019, 12:14:45 AM
Are we neighbors?
I'm in the Kaslo area along Kootenay Lake, little ways away
I may be skinny but I'm a Husky guy

Woodmizer LT40HDG24. John Deere 5300 4WD with Loader/Forks. Husky 262xp. Jonsered 2065, Husky 65, Husky 44, Husky 181XP, Husky 2100CD, Husky 185CD

Al_Smith

That thing looks like it had been ran with well head crude oil as mix oil .It almost looks like it somehow had sucked bar oil into the crankcase .It's a wonder it ran at all .It's a clam shell design and I'm not exactly certain about the location of the oil tank  or if it even could leak into the crankcase but I have the parts list .I'll take a look see .

Al_Smith

Looked at the IPL and evidently the oil tank is in the framework like most Stihls .I don't see any gaskets shown so I might assume they used sealant which they do list .It's only a guess weather it could leak that way or possibly via the crankcase seal under the oil pump or for that matter if it's leaking at all . 
I never paid much attention to Stihl clam shells but I do have box full of parts from 029 /039  in one of my sheds I rob parts from from time to time .It's buried under a bunch of junk and might take me a couple of hours to find it .

hms11

It's possible this is "old" damage that has somehow not catastrophically failed.

I inherited this saw from my grandfather, a long time time logger/forester who sometimes had some..... outdated notions when it came to fuel/oil choices and mixes. He definitely knew his stuff when it came to logging, felling, anything at all involving turning a tree into tree products, but his machine knowledge was sometimes suspect. Since I've owned it it has only seen Stihl oil and ~40:1 mixes, what it was running on before I owned it is completely unknown.

The crazy part is that I've been running this saw for YEARS. I never thought it was a powerhouse, but all my reading on 039's was that they weren't a super powerful saw for their size so I figured it was just the nature of the beast. It was also the reason I was muffler modding it while giving it a tune-up. I had never really looked at the piston before when changing plugs so I have no idea how long it has been like this. 

Back to the repairs, where do you guys in Canada buy your saw internal parts? Right from a Stihl dealer? I've never rebuilt a 2 stroke before, but I've been inside plenty of 4 strokes so I can't imagine this is beyond me if I just pay attention and take my time. Also, do you think I should just order a piston and ring set or should I consider just buying one of those complete aftermarket engines (farmertech?). I don't see any marks on the bore from what i can see through the exhaust port or sparkplug hole so I think the cylinder survived no issue.


ZeroJunk

The clam shell motor is physically separate from the bar oil tank.

Al_Smith

Quote from: ZeroJunk on December 06, 2019, 08:05:42 AM
The clam shell motor is physically separate from the bar oil tank.
Seeings that then if,repeat if it's ingesting bar oil the logical place would be a faulty crankcase seal under the oil pump .Now I've never personally seen an oil burner Stihl  but I have on other saws .Again it's only a stab in the dark .Geeze I'll bet that thing smokes like it's burning soft coal or pine knots . ;D

hms11

It's really odd, because the saw doesn't smoke at all really.

I agree with everyone here, but oddly enough this thing defies all odds. 

It has a bit of smoke when its still warming up and you throttle it up but nothing worse than any other small 2 stroke I've ever owned. 

It's a serious head scratcher, thats for sure. 

hms11

One more question,

As I wait for the guru's here to point me in a direction for where to find parts, I did some googling. 

I found SawParts.ca, the only Canadian saw parts supplier I've found online so far. They seem to have a cheap and expensive cylinder kit and I wasn't sure if the upgrade was worth it (not saying I'm buying from here, just noting the differences in products available). 

The "upgraded" version is from Cross Performance and has a Nikasil coating. I'm pretty sure this is the coating used in lots of snowmobile engines, so I'm somewhat familiar with its usage in 2 stroke engines but I wasn't sure if there was a real advantage to it in a saw that made the upgrade worthwhile. 

Full disclosure: Seeing as this is a saw I inherited from my now passed grandfather it has sentimental value to me. I realize the 039 is a "consumer" or homeowner grade saw and really likely isn't worth much, and as such should probably get the cheapest possible repair. However, if the Cross Performance kit offers genuine value over the base kit, it will be worth it for me. I have no problem spending more money on this saw than it is worth in order to continue to be able to use and enjoy my grandfathers saw with a bit more performance, or reliability/longevity.

I really wish I had his 026 that he had as well. 

sawguy21

If you are going to that much work imho it's worth doing right the first time. The cylinder will have a nikasil or chrome lining depending who makes it, I have had problems with chrome peeling so don't suggest that route. If you want genuine Stihl parts then you need to go to a dealer, they are not allowed to sell online. Aftermarket you are on your own, some are apparently good but many are a waste of money. I have only used oem so can't make any suggestions.
old age and treachery will always overcome youth and enthusiasm

Mad Professor

Whats inside of your muffler look like?

That beast is running way too rich.

I'd pull it down and de-grease the top end.  Retune the carb.

Mad Professor

Avoid those made of "Chinesium" cylinder kits.  You'll spend a day or two fixing what is wrong and getting it to fit right.

OEM is the best.  Only other piston I'd use is Meteor (Italian).

hms11

Quote from: Mad Professor on December 06, 2019, 11:45:46 AM
Whats inside of your muffler look like?

That beast is running way too rich.

I'd pull it down and de-grease the top end.  Retune the carb.
It didn't look bad when I was muffler modding it. No build up, no gunk crap or carbon above what you would see normally on a 20+ year old saw that has never been rebuilt. 
I'll snap some pictures when I get home. 
I'm thinking, with how gross the top of that piston looks that I am likely best off ordering a Piston and Cylinder kit as opposed to just a piston. Hate to get it all torn down and see a bunch of wear, scuffs or other damage on the walls.

hms11

Quote from: sawguy21 on December 06, 2019, 11:43:44 AM
If you are going to that much work imho it's worth doing right the first time. The cylinder will have a nikasil or chrome lining depending who makes it, I have had problems with chrome peeling so don't suggest that route. If you want genuine Stihl parts then you need to go to a dealer, they are not allowed to sell online. Aftermarket you are on your own, some are apparently good but many are a waste of money. I have only used oem so can't make any suggestions.
I don't disagree, I know in the automotive world (where I'm most knowledgeable) aftermarket parts range the gamut from not worth even looking at, to better than OE in certain applications. I wasn't sure if the small engine world worked the same. I kept running across these "Cross Performance" kits and wasn't sure if they were a legit option that was equal to OE or if they were just another cheap china knockoff. They say they are Nikasil lining as opposed to chrome so that is a plus. When I googled them the results seem all over the board, with some guys swearing they are a great option and others saying they are no good. 
Looks like I'll price out a Stihl piston and cylinder while I'm at it. The cylinder might be fine, but with the way that piston looks I'm not that confident. 

Mad Professor

Don't put a "Chinesium" cylinder in it. It won't run as well......much lower quality, and fitment issues

Clean up the OEM. It's easy.  Check P/C clearance, it should be ~0.002-0.0025" new. Over 0.004" and it's way worn.  Use a meteor or OEM pistion if needed.  Both will have quality rings. If you just need rings, get Cabers.

A OEM gasket set will come with new crank seals, consider that for an old saw.

Al_Smith

It might be nothing but a goobered up piston .The cylinder  might be fine .You go hanging an OEM piston and cylinder on that thing and in addition to a carb, bearings and seals you'll exceed the value of the saw when it was brand new .Just my opinion on old saws .

If it were say an 064 -066 -084 it might be worth it but not an 039 . 

hms11

Quote from: Mad Professor on December 06, 2019, 12:33:31 PM
Don't put a "Chinesium" cylinder in it. It won't run as well......much lower quality, and fitment issues

Clean up the OEM. It's easy.  Check P/C clearance, it should be ~0.002-0.0025" new. Over 0.004" and it's way worn.  Use a meteor or OEM pistion if needed.  Both will have quality rings. If you just need rings, get Cabers.

A OEM gasket set will come with new crank seals, consider that for an old saw.
Thanks for the info, sounds like a plan of attack!
I was already thinking of putting new crank seals on it while I was in there, they seem relatively cheap to not do while I'm opening it up anyways. 
Is there a clamshell gasket for these saws or just silicone? I don't seem to be able to find a gasket and most of the videos I'm watching guys seem to be just using silicone to seal them back up. 

hms11

Quote from: Al_Smith on December 06, 2019, 12:33:49 PM
It might be nothing but a goobered up piston .The cylinder  might be fine .You go hanging an OEM piston and cylinder on that thing and in addition to a carb, bearings and seals you'll exceed the value of the saw when it was brand new .Just my opinion on old saws .

If it were say an 064 -066 -084 it might be worth it but not an 039 .
If this saw didn't have sentimental value, I would agree with you 100%, it's just an old homeowner grade saw, nothing special, nothing impressive. 
However, it was my late grandfathers saw, and so I know that I'm probably going to spend more than I should on a saw that isn't worth it. 
I'll do a tear down first for cylinder inspection. I was going to do crank seals while I was in there but the carb seems to be fine and I'll see what kind of shape the bearings are in. 
Worst case scenario, I'll be off to my local Stihl dealer for a new saw, while my 039 gets tidied up and put on a shelf for memorabilia reasons. 

Al_Smith

If that's the case I'd say go for it .FWIW I have my dads old McCulloch and my brother has his Roper .Plus I have my great grandfathers toolbox of machinests tools that went through 4 generations with my dads journeymans card in the top drawer .

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