ms440 Rebuild

[Carolina Diesel]

I recently purchased several saws to rebuild (440, 441, 290) and I will be rebuilding the 440 first. This is my first rebuild and was hoping to get advice on how to do this. The saw is disassembled and I have attached pictures. The piston is in horrible shape and it appears the cylinder walls has a few chips. Where do I begin? I have never rebuilt anything. I am ready to order parts and would like to do it all at once. I have read on this site that I need an OEM jug, meteor piston, caber rings, and a gasket set? What else do I need to check and consider? Thank you in advance.View attachment 298159View attachment 298160View attachment 298161View attachment 298162View attachment 298163View attachment 298159View attachment 298160View attachment 298161View attachment 298162View attachment 298163

 

[southbound]

Need better pic's of the cylinder to see whats chipped...

Also do You know what caused that damage????

Are the bearings ok???

 

[old-cat]

If you don't have a STIHL service manual and parts manual, you'll need them. I'll give you the link if you desire.

 

[Stihlofadeal64]

By the looks of your piston you had a major failure of sorts. Looks like something "turned loose" (did it brake a ring?). Not knowing what the cylinder looks like (blurry picture) and not knowing what shape the crank bearings are in make quite a few variables for me to answer questions.

 

[Mastermind]

Yep.....an oem jug is a must. oke:



:spam:

 

[Abflyboy]

Yep.....an oem jug is a must. oke:



:spam:

:beat_shot:

 

[Carolina Diesel]

I am not sure what caused the damage. I bought a Stihl lot and I am not sure what caused the damage. I just received the service manual and I am about to read that to dig a little further. I am certain I need a new cylinder and piston. I found this cylinder and piston on sawagain, any opinions? Stihl 044 MS 440 Cylinder and Piston Ring Assembly OEM

I am not sure about the bearings. How should I test this? My crankshaft does not appear to be damaged and it seems to operate properly.

On the picture looking down at the piston and crankshaft, can anyone tell if my case is lined up properly? The opening doesn't form a perfect circle.

 

[Carolina Diesel]

By the looks of your piston you had a major failure of sorts. Looks like something "turned loose" (did it brake a ring?). Not knowing what the cylinder looks like (blurry picture) and not knowing what shape the crank bearings are in make quite a few variables for me to answer questions.

It did not break a ring, but they are not seated properly now.

 

[Carolina Diesel]

Additional photos

View attachment 298230View attachment 298231View attachment 298232View attachment 298233View attachment 298234

 

[LegDeLimber]

Fellers, that cylinder is in the witness protection program.
y'all'll just have to surmise the damage.

kidding aside for a sec,
Carolina, I don't kow about cell phone cameras (too broke to own one)
But if you're shooting with a regular camera here's a thought:
On most cameras if you pick a surface or "false target" (like a table top)
at the same distance from the camera as the the cylinder will be from it
when you take the cyl pic.

could be a box etc, just something big enough to let the camera get
a bounce back from and then find a range to set focus.

Now while pointing the camera at the false target
press the shutter a half press till ya feel the first faint hint of a stop or click
then keep holding the button at half press and re-aim the camera
into the cylinder and while keepin 'er steady press the button all the way
and get the pic.
It may take a bunch of tries or might get lucky on first shot.
...took me a dang bunch of tries to get a pic down a sparkplug hole
at a decent focus .
I had touse something to rest my hand against to stop blurring the pics.

If you already knew all this, my apologies for the long spiel,
was just hoping to help a bit.
Cause as you seem to have already taken notice of, get some pics up and these folks will be all over your project!

 

[Carolina Diesel]

How about these? The pics are showing up clear on my computer, but like I said earlier, I am pretty confident the cylinder has to be replaced.

View attachment 298237View attachment 298238View attachment 298239View attachment 298240View attachment 298241

 

[LegDeLimber]

nice shots.
I expect folks will want to know what the object was that went through the motor.
So I'd say do your best to figure out what it was and if possible ,
why it had the opportunity to get loose and be in there.
Cause you know these guys will want to know.

sorry i'm not one of the "go to guys" just hoping to help get your
prep ready for the main crew.
and I'm gonna shut up for now.

 

[rmh3481]

Since you have no history, I would replace the bearings and the seals. Here is a thread that may help; http://www.arboristsite.com/chainsaw/131284.htm

This would be a good candidate to test a Masterminded top end.

 

[Mastermind]

If you are trying to get it back in service as cheap as possible for your own use that jug will run as long as all those chips and gouges are below the height of the exhaust. In other words, you can get away with places in the bore that the rings don't pass over.

That said........you should replace the cylinder if you want to rebuild that saw and sell it or use it in heavy use.

If it were mine I would completely disassemble it, clean every piece and replace anything that is suspect. Many times the bearings will be fine.....but we use an ultrasonic cleaner and a very close inspection to be sure.

We take trade ins on saws.......and/or sell saws that are rebuilt for a fair price if you decide that you are in over your head.

 

[71dart]

Additional photos

View attachment 298230View attachment 298231View attachment 298232View attachment 298233View attachment 298234

Are both of the piston pin c-clips still in place?

 

[Mastermind]

71 Dart huh?

I had a sweet '69 with a 340......

 

[Carolina Diesel]

Are both of the piston pin c-clips still in place?

No, the c-clips are not in place. The saw was broken doen when I received it, so it may have been removed my the previous owner.

 

[Carolina Diesel]

Since you have no history, I would replace the bearings and the seals. Here is a thread that may help; http://www.arboristsite.com/chainsaw/131284.htm

This would be a good candidate to test a Masterminded top end.

Thank you, I'll check the link out. Considering this is my first rebuild, I am very hesitant to split the case, but I want to learn and I want to do it right, so I am game. Has anyone looked at the very first picture in the set and can tell me if the case is supposed to sit offset like that?

 

[Carolina Diesel]

I do not care about being cheap, I want to do this right. I found a used oem piston and jug on the bay that look to be in good shape with 170 compression, in Leesburg, FL, I can have shipped to my house for $145. I can have everything I need for under $200 (not including tools I need to buy). I am willing to discuss trade-in's with you, I will list what I have below, but I don't want to derail this thread so pm me to discuss further. Stihl: (1) ms440, (2) ms441, (1) ms290, (1) TS400, (5) FS250, (1)FS85, (1)BG85

If you are trying to get it back in service as cheap as possible for your own use that jug will run as long as all those chips and gouges are below the height of the exhaust. In other words, you can get away with places in the bore that the rings don't pass over.

That said........you should replace the cylinder if you want to rebuild that saw and sell it or use it in heavy use.

If it were mine I would completely disassemble it, clean every piece and replace anything that is suspect. Many times the bearings will be fine.....but we use an ultrasonic cleaner and a very close inspection to be sure.

We take trade ins on saws.......and/or sell saws that are rebuilt for a fair price if you decide that you are in over your head.

 

[71dart]

71 Dart huh?

I had a sweet '69 with a 340......

I traded a '70 340 engine for a '76 powerwagon last year. It's a good fire wood hauler but i'm gonna miss that 340...:msp_sad: