Stihl 08s Project Rebuild

[Vintage Engine Repairs]

Hi, another project and hopefully challenges to overcome.

This time a stihl 08s again for the owner of my local Stihl shop.






It’s having a full overhaul as well as some fabrication of a new handle brace pocket (notorious for mag rot and this is no different). More on that later.


I did the tear down today and there are 3 notable mentions so far.


First, removing the clutch side key.


Someone was in this saw before me and had a good go at removing it unsuccessfully, it was well and truly stuck and beaten up.


I initially tried getting a pick inbeteeen the flywheel and key to no avail. Then I tried carefully with a screwdriver with no luck.


Then I tried some penetrant and the above methods with no success.


Then I tried heat and penetrant and the above being very aware not to go above 150c checking with an IRT as it would start to affect the metal temper. Nothing..


Then I decided to drill a 4mm hole in the key and tap the threads and pull it out. Knowing the key is soft I did question if the threads would just rip out. Therefore if that failed my backup was to then tap to a 4mm thread repair. If that failed I’d move up to 5 and so on.


Anyway, drilled, tapped and used two hammers and after a few knocks of the hammers the key eventually came out.

 

[Vintage Engine Repairs]

The key,



No damage to the crank (I stopped drilling as soon as I felt slight resistance / the inability to keep going) and it hardly left even a mark.

 

[Vintage Engine Repairs]

The next notable mention is the piston... once again, someone had used a metal piston stop and damaged the crown of another piston...

The damage, just like on the 045 build I did, went through and cracked the underside. It will be replaced...





I have seen so many good pistons damaged from misuse of rope or metal piston stops...

 

[Vintage Engine Repairs]

The third notable mention was when the previous person working on the saw wasn’t careful with how he had put the wires back under the flywheel. I always double check wires won’t get caught and this is why.. it was on the outside of the stator plate and got abraded away. There wasn’t any spark on this old girl and here is why.





Cracked HT lead would cause grounding too:






Ah yes, and a 3rd reason this wouldn’t make spark.. who needs an air gap anyway?! It’s almost like they tried to purposely avoid getting spark! (Maybe he needed an excuse with the mrs for a new saw?)

 

[Vintage Engine Repairs]

The saw is apart and time to build the AV pocket. The foundation is now set, now to just build it up.

 

[Sagebrush33]

Very nice work sir.

 

[Vintage Engine Repairs]

Very nice work sir.

Thanks Sage much appreciated

 

[Huskyvarnya Saws]

Top notch work with attention to detail as usual! Forgive my ignorance, but what exactly going on in that last set of pics you posted? Did the section of the case where the handle attaches rot out?

On a side note, I sure am glad I didn't buy one of those metal piston stops when I started working on saws. One of the times where going the cheap route with the rope paid off. I'm sure it's just a matter of time before I run across a damaged piston like that.

 

[Vintage Engine Repairs]

Top notch work with attention to detail as usual! Forgive my ignorance, but what exactly going on in that last set of pics you posted? Did the section of the case where the handle attaches rot out?

On a side note, I sure am glad I didn't buy one of those metal piston stops when I started working on saws. One of the times where going the cheap route with the rope paid off. I'm sure it's just a matter of time before I run across a damaged piston like that.

Hey husky, yes correct it’s a pocket that the handle bar brace sits in for rigidity. They are notorious for rotting away, this is the second one I have built back up.

 

[Vintage Engine Repairs]

A small snippet of working the mount

I’m getting closer - using a few different dremel attachments, hand sanding and small files. Quick wash (hence why it’s wet) and pictures taken

 

[Vintage Engine Repairs]

I thinned down this second to last layer with acetone to fill in the air bubbles in the previous layer and applied with a brush before going over and shaping it with a wet finger to cut down on sanding later.

I’ll sand it in the morning, do another final coat if needed and then I’ll spray paint the repair, strip the old powder coat area where the muffler heat has bubbled it as well as paint the shiny mag and missing paint areas to blend it in and call it good.

I’m not sure if many enjoy this sort of resto, but it may be helpful to someone in the future.



Here is a picture of removing discolouration and staining on the powder coat using acetone before adding new paint, this way it will match with much less of an obvious transition, proceed with caution for obvious reasons using acetone on any paint or powder coat - very quick very light rubbing, don’t let any acetone sit and don’t do it for any longer then necessary. A before and after picture as an example.

View attachment 294951

 

[Sagebrush33]

I’m not sure if many enjoy this sort of resto, but it may be helpful to someone in the future.

I do enjoy seeing your resto work and find this valuable info should I ever happen across an 'old iron' saw, considered junk, that someone is getting rid of. I won't be timid of paying a few bucks for a notable saw needing some love.

 

[Huskyvarnya Saws]

Wow, that looks great! I'll be taking note of that acetone tip as well. It really cleaned that discoloration up nicely. What product did you use to build up that pocket with?

 

[Vintage Engine Repairs]

 

[Vintage Engine Repairs]

Scratching my head on the best way to repair this crack...

Drill a small hole at the end, clamp and Jb weld from the underside?

Strip paint, drill hole at the end, v groove it from the top, repair with Jb from above, sand flat and repaint whole thing?

drill a tiny hole, fill it with JB weld and leave?

Replace cover?

 

[Sagebrush33]

I vote for fixing from above and repaint.
You've spent some quality time on this old girl already....