STIHL The Official Stihl Chainsaws Thread

[lehman live edge slab]

Went to a garage sale today bought both saws for 300$, both run great. 046 and 066 round top

 

[lehman live edge slab]

Stihl 042/048 bearing, outer race is turned down.

 

[lehman live edge slab]

German skf bearing

 

[lehman live edge slab]

I’ll use my calipers to show measurements on it tomorrow. Did quick search and didn’t find a match to the number and I have no idea if you can get a bearing and turn the outside race down to match

 

[DND 9000]

Measurements on this bearing are: 20x42x14

 

[lehman live edge slab]

Seems to be running just fine. Guess I assembled the carby correctly.

Very nice 042, I have a couple in about the same shape just need to put the pto bearing and new seals in. Definitely an older one probably early to mid 70’s because of the old symbol. Chain brake or none, also the clutch disconnect style or brake band style if it does.

 

[lehman live edge slab]

Measurements on this bearing are: 20x42x14

Was just going to measure how much the outer race is machined back, wondering if a guy can machine this step down or if it’s too hard of steel in that race

 

[Al Smith]

I had thought perhaps on the 042/048 main it might be possible to grind the race and chamfer the ID with an ID/OD grinder .You'd have to use an ultra-sonic to clean it afterwords if that would work .I think the races are so hard about the only thing that could even make a dent would be ceramic cutters .
Now I've used same to cut down water pump arbor shafts in a lathe that carbide would not even touch .They glow the nicest cherry red .

 

[heimannm]

I have an MS280 from one of the fellows at work, piston still has machining marks looking through the exhaust port, but only 125 PSI compression. It will start and run but will hardly accelerate without dying unless you really toy with the throttle. If you open the throttle too quickly it will die, take three pulls with the throttle wide open to get it going again.

I've done my best to pressure test as it did seem to change idle as I rotated it from side to side. I can get the crankcase to hold pressure depending on where the piston is in the stroke...BDC will hold pressure, TDC will hold pressure, in between it won't hold any pressure...any suggestions on where to go next? I did check the seals with soapy water under pressure and cannot detect any leakage.

Mark

 

[lehman live edge slab]

Isn’t that the saw that had stihls first try at the electronic carb? If it is the one I’m thinking then maybe the carb went lean on it and started to wipe the rings out. I thought about buying one once and was warned against it.

 

[lehman live edge slab]

Any opinions on what I should do with the choked up epa 066 I just bought to get it to cut better. I planned on opening the muffler and pulling the limiters so I can retune it. Is this enough to bring back close to the older 066 power wise or do I need to work the ports since my manual talks about the optimized ports for the new muffler to meet epa standars. Otherwise I do have a non decomp cylinder of an 066 flat top red light that has a bad crank I can put on it. Any opinions and why do you think this is the way to go.

 

[lehman live edge slab]

And what does magnum exactly mean on these saws? No dual port muffler or any other specific things I see. Just a sticker that means nothing anymore? My other thought is to mod this newer 066 and get a crank for my flat top red light. That way I’ll be able to have an 064, 066 red light and this round top 066 mag

 

[heimannm]

This one at least has no electrical connections on the carburetor.

Mark

 

[lehman live edge slab]

Ok just a thought i didn’t know if they made it both ways or not. Must be a ms 280 and an ms 280c

 

[Al Smith]

Only a suggestion on that 280 .If you have a borescope you might be able to analyze weather the cylinder bore is either barrel shaped or otherwise eccentric in the mid stroke position .Highly unlikely but possible .

 

[PogoInTheWoods]

I can get the crankcase to hold pressure depending on where the piston is in the stroke...BDC will hold pressure, TDC will hold pressure, in between it won't hold any pressure...any suggestions on where to go next? I did check the seals with soapy water under pressure and cannot detect any leakage.

Mark

Where are you injecting the pressure? The shop manual says to use the test point on the intake test flange with the piston at T.D.C. If the pressure holds, the case is presumed to be tight and has passed the pressure test. I don't necessarily agree with that simple of a test being conclusive, but that's what's in the shop manual.

They also suggest a vacuum test for the seals but don't specify the piston position. If vacuum holds at 0.6 of a bar or doesn't rise above 0.3 for at least 20 seconds the seals are presumed to be in good condition.

Rather minimal (and forgiving) parameters if you ask me, but that's what's in the MS280 service manual nonetheless.

No reason I can think of that a case would be tight at both T.D.C. and B.D.C. but not in the middle unless the seals were leaking at that point of the crank rotation or something unusual pressure-wise in the combustion chamber was possibly offsetting the seal of a compression release (if present) at that point in the stroke.

 

[lehman live edge slab]

The 066 cleaned up great, only stuff done is removed the limiters and opened up exhaust. The 046 isn’t perfect but still looks decent and runs great.

 

[heimannm]

I blocked the intake and exhaust and connected the pressure through an adapter in the spark plug hole. I do have an "endoscope" attachment for my phone, I will try to have a look down the cylinder and see what I can see.

Evidently to do it the Stihl way you need some special adapter which I don't have at the moment. If anyone has a photo of the adapter it might provide me with some ideas.

Mark

 

[Semotony]

View attachment 192282

How much for the stack for 066 carb inlet. PM me to arrange

 

[PogoInTheWoods]

Evidently to do it the Stihl way you need some special adapter which I don't have at the moment. If anyone has a photo of the adapter it might provide me with some ideas.

This is the common one.

​

This is one I cobbled together that serves the same purpose with considerably less elegance. It covers the impulse port on saws that have the hose routed to the base of the carb mounting bulkhead. I just use a blocking plate for saws with the impulse hose through the carb mounting bulkhead and use the impulse hose itself as my test point on those. I use wrist pins for spacers on the mounting studs.

​

I don't see why a spark plug adapter would behave any differently than an intake based injection point or why the position of the piston should make any difference in the results of a vac/pressure test. Never had anyone explain it to me or seen it in print anywhere. I've never seen any evidence of it in my own testing over the years either. The only thing changing is the immediate "volume" of area being tested relative to the injection point..., if the rings actually created a perfect seal between the top and bottom of the piston which they obviously do not.

The same goes for the throttle having to be wide open for an accurate compression test. Never seen any evidence of that, either. May be easier to pull over with less air obstruction at the intake but isn't going to change how much compression the rings are capable of providing in the combustion chamber.

Regardless of test injection method/location for vac/pressure testing, I generally rotate the crank under both pressure and vac to ensure I end up with the same reading after a couple of revolutions. It will bounce relative to the volume change at the injection point but should return to the original reading if the saw is tight. I use 6~8 lbs of pressure and 12 ~ 15 inHg of vacuum with a MityVac 8500.