066 meltdown and rebuild

Hey guys, not exactly the way I wanted to introduce myself to the site but here it goes...

Long time stalker, first time talker. Traded my cream-puff 038 (I know) last week for an 066. Saw had good compression, new clutch (more on that later) and overall checked out okay. Guy I traded with admitted that he hadn't had any time to look the saw over, but lent it to me to check out in a gesture of good faith.

Me being the ADD type, I forgot to pull the clutch cover for inspection, I only looked at the new clutch and said "sweet". Saws, bars, chains and cash exchanged hands and I was stoked! Thing ran like hell!

Saw started to get hot, lose power and lost compression all in about 2 minutes. Pulled the muffler, saw the scoring and knew it was done for.

Found this under the clutch cover:


Oiler has seen better days:


Piston scored on exhaust side:


Intake side:


Small nick in the wall... What could have caused this?

Intake side in context with nick:


Exhaust scoring:


Case prior to clean up (anyone else see heat marks?):


Con rod upper end:


After about and hour of cleaning out the sludge that saw packed in tight.


Crank has no play and spins freely. Plan is for a Bailey's BB kit and some very mild porting. But before all that happens, should I split the case and replace the gasket?

Wow, that looks like fun... Always sucks to get something you think is fine, that ends up being messed up...

Mike

Welcome! Were both of the circlips intact? My opinion is since you're this far,why not replace the bearings and crank seals while your at it? Saw looks like it was used hard,so seals and bearings would be cheap insurance,IMO.By the way, this is a good lesson.....NEVER,EVER get rid of an 038.......lol

barton174 said:

Wow, that looks like fun... Always sucks to get something you think is fine, that ends up being messed up...

Mike

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True. Shame on me for not looking into it further...

daddy66 said:

Welcome! Were both of the circlips intact? My opinion is since you're this far,why not replace the bearings and crank seals while your at it? Saw looks like it was used hard,so seals and bearings would be cheap insurance,IMO.By the way, this is a good lesson.....NEVER,EVER get rid of an 038.......lol

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Yes, both clips were intact.

You guys are gonna hate me for selling this:






Made in West Germany, factory stickers, the works. "Grandma only used it to cut alder on Sundays..." That story. Got it on flea bay for a song. Shoulda kept it.

Yep...pretty stupid to rid yourself of an 038 like that....It was an 038 super too. But enough ball busting, it looks like your 066 lost a circlip, or possibly a bearing came loose and it lodged itself in between the transfers. Something hard did that. As for the intake damage??? Bad/no filter?? Not sure there. You got the shaft my friend. And what's up with that oil pump?

wigglesworth said:

Yep...pretty stupid to rid yourself of an 038 like that....It was an 038 super too. But enough ball busting, it looks like your 066 lost a circlip, or possibly a bearing came loose and it lodged itself in between the transfers. Something hard did that. As for the intake damage??? Bad/no filter?? Not sure there.

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Standard Stihl HD filter, a little old, but not in bad shape. Do you think that the ding/nick and the meltdown are related?

I had a serious "DOH!" moment after I signed up here and searched under "038".

Live and learn, I guess.

It's ugly, but not much more so than most of the units I get in from pro users. Give it a good bath in the parts cleaner. Pull the flywheel and crank seals. Flush the bearing from the outside inward. If after doing so the bearings have no play and feel smooth, drop some new seals in and redo the top end.

This unit sucked alot of debris. Thats why I'd flush the lower bearings. Likely the bearings chewed on a bit of it, but also likely they are in good shape if you feel no end play.

Sucks that you have to do the rebuild as your 038 looks like it was a nice unit, but you'll end up about even on the deal. Good used 660 is about $550-600. Good used 038 super ~$300. You'll put $200 or so into that saw and have a nice unit.

In the mean time, keep searching locally for another nice 038

Welcome to the forum first of all!!

That sucks about that trade deal!......That poor old 066 has been eating some dust!......

Phramer Phil said:

Standard Stihl HD filter, a little old, but not in bad shape. Do you think that the ding/nick and the meltdown are related?

I had a serious "DOH!" moment after I signed up here and searched under "038".

Live and learn, I guess.

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It might have a nice HD filter on it now, at some point that filter either wasn't on or wasn't sealed up properly. It ate alot of dirt.

Phramer Phil said:

Standard Stihl HD filter, a little old, but not in bad shape. Do you think that the ding/nick and the meltdown are related?

I had a serious "DOH!" moment after I signed up here and searched under "038".

Live and learn, I guess.

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Id say it ran for a while without that filter in place. If the damage is related, the piston should look destroyed where it aligns with that big old gouge. Something lodged itself between the cylinder wall and the piston...no other way that damage happened.

There is a known problem with the 066 air filter system sometimes not sealing reliably. It is very poorly designed, IMHO. Dunno if that is what happened in your case, but it happened to me. Easy fix, ask me again when you get the saw put back together.

Do you have a pic of what was underneath the air filter before you cleaned that up ? Did it look like dust was leaking by the filter ? If the filter was sealing, that area should be squeaky clean.

Looks like someone installed the clutch hub without engaging the oil pump pawl, forcing the pawl to rub against the pump. Been there, done that.

066 projects are fun, though. I'm always looking for an 066 project saw.

If I were you, I'd hold off on ordering the BB kit until the 2nd generation kits are released.

Thanks for sharing.

For the wrong reasons you have a 066 rebuilt in your hands. Keep us posted with lots of pictures of the progress of your work.

Nice 038 you had there.

Phramer Phil said:

You guys are gonna hate me for selling this:

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No, I dont hate you for selling it.....I hate you for not selling it to ME

Paul001 said:

...This unit sucked alot of debris. Thats why I'd flush the lower bearings. Likely the bearings chewed on a bit of it, but also likely they are in good shape if you feel no end play.

In the mean time, keep searching locally for another nice 038

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I swear on a stack of manuals that I will keep, love and cherish the next 038 that comes into my possession.

jockeydeuce said:

Welcome to the forum first of all!!

That sucks about that trade deal!......That poor old 066 has been eating some dust!......

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Thanks! Indeed it has.

Paul001 said:

It might have a nice HD filter on it now, at some point that filter either wasn't on or wasn't sealed up properly. It ate alot of dirt.

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I agree.

mtngun said:

There is a known problem with the 066 air filter system sometimes not sealing reliably. It is very poorly designed, IMHO. Dunno if that is what happened in your case, but it happened to me. Easy fix, ask me again when you get the saw put back together.

Do you have a pic of what was underneath the air filter before you cleaned that up ? Did it look like dust was leaking by the filter ? If the filter was sealing, that area should be squeaky clean.

Looks like someone installed the clutch hub without engaging the oil pump pawl, forcing the pawl to rub against the pump. Been there, done that.

066 projects are fun, though. I'm always looking for an 066 project saw.

If I were you, I'd hold off on ordering the BB kit until the 2nd generation kits are released.

Thanks for sharing.

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Everything was nice and clean. Few paint chips off of the threaded standoff made make me a little suspicious though.

I'll be getting in touch with you soon, thanks!

caotropheus said:

For the wrong reasons you have a 066 rebuilt in your hands. Keep us posted with lots of pictures of the progress of your work.

Nice 038 you had there.

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daddy66 said:

No, I dont hate you for selling it.....I hate you for not selling it to ME

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I can feel myself slowly becoming "that guy" on the forum.

"hot tanked" a few parts. (I didn't leave all of them in there.) My girlfriend is gonna KILL me if she sees this. Only worse thing in her mind would be putting the cat in the microwave.


Eww.


I'm just gonna go ahead and split the case. Came this far, and you guys made a valid point in the idea of "cheap insurance".

Phramer Phil said:

"hot tanked" a few parts. (I didn't leave all of them in there.) My girlfriend is gonna KILL me if she sees this. Only worse thing in her mind would be putting the cat in the microwave.
.

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Trust me the moment you even thought about putting the saw in there, she already knew. She might not have known exactly what it is you were doing, but the air suddenly became very still...

Phramer Phil said:

I can feel myself slowly becoming "that guy" on the forum.

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LOL.. I wouldnt worry about it too much.......... someone else,me maybe, will do something stupid pretty soon. I'm not even a real stihl head,but I would say an 038 is probably the best saw ever made in that category. A lot of guys feel the same way. If you find another one ,buy it........

daddy66 said:

LOL.. I wouldnt worry about it too much.......... someone else,me maybe, will do something stupid pretty soon. I'm not even a real stihl head,but I would say an 038 is probably the best saw ever made in that category. A lot of guys feel the same way. If you find another one ,buy it........

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Everyone wants one, but the last two 038 Supers I had up for sale took weeks to find a home. 066's, 026's, 200T's...move quickly. 038's, low profit and weak movers.

Double check your big and small end rod bearings to make sure all the needles are there. Some foreign object definately went through that engine. Good luck on the rebuild. What are you doing for a P&C?