Fixing a 15 year old 066 Magnum/need advice

[Funky sawman]

You gots yerself a great saw to build there. No better model that a 660 066 to learn the in's and outs of saws

 

[Jungleman]

The big end bearing of the crank isn’t replaceable, right. Still hard to say for sure based on that vid above. Does the shaft have any vertical play if you lift it away from the lobes? There’s a needle bearing in there that needs to be inspected.

Cant really feel any vertical play, no. Only movement is I can slide it to the side a tiny bit as shown in these two pics. One of them you can see the bearing on the right side, then I slide it over and you can see the bearing on the left side. That normal?

 

[Wonkydonkey]

about the clanking noise... you need to work out where the piston is when it clanks ie top, bottom or middle of the cylinder.
I can see a gasket in the pics so doubt it’s the top
I'm guessing friction on the exhaust side is tilting the piston and the bottom of the piston it’s contacting the crank
And in this pic you posted, this bit don’t look right.
Was there any wear on this side of the wrist pin and piston. does the Bearing have much play..on the wrist pin ?.
I'll dig out a thread and post the link below.

This is the thread I think is worth you reading.. the vid in post 37
http://opeforum.com/threads/064-crankrod-knock.18871/page-2#post-979824

Btw, what’s the two saws you got under your bench ? 1 looks like a 261

 

[Jungleman]

Btw, what’s the two saws you got under your bench ? 1 looks like a 261

Lol something about human nature that makes us curious eh? It's a 290, a 391 right of that, over to the right is a itty bitty 170 and then the big ole heavy sumgun 880 way to the right.

 

[huskihl]

I’d get the cylinder cleaned up and get a new piston in it before I felt for anything more. It’s hard to tell what you’re dealing with when you have a scored up piston like that.

 

[BuckthornBonnie]

Cant really feel any vertical play, no. Only movement is I can slide it to the side a tiny bit as shown in these two pics. One of them you can see the bearing on the right side, then I slide it over and you can see the bearing on the left side. That normal?

It’s normal to be able to move the rod right/left within spec, yes. Excessive movement or play is bad, though.
Does the crank have any play when wiggled by hand? Both FW and pto side.

 

[Jungleman]

@Wonkydonkey no play on the wrist pin. I saw what you meant on that piston, a slight bit of damage.

@BuckthornBonnie the crank felt solid and no play at all When I pull on the rod.

@huskihl i think that’s the conclusion I have also come to. I’m gonna order a new piston and gaskets.

I’m gonna clean the saw parts and clean that jug out, by hand. Also gonna order a new decompression valve as it is permanently pressed in and doesn’t pop out anymore.

I’ll report back in a few weeks!

 

[Wonkydonkey]

I think the decomp, is ment to pop close as the compression increases and if it fires, if you’ve get very little compression then it’s not going to close..

But if your buying stuff, it’s one thing less to worry about,, just remember chicom style valves had a tendency for the plastic to fall off and the rod dropped into the cylinder

 

[Jungleman]

What’s a good off brand decomp valve you would recommend? I’m gonna call my stihl dealer tomorrow and ask him how much a real oem one is. A small essential part like this I usually get the real deal.

 

[Tugg]

[QUOTE=" I’m gonna call my stihl dealer tomorrow and ask him how much a real oem one is. A small essential part like this I usually get the real deal.[/QUOTE]
That is the same attitude I walk into every saw shop with, $3 a screw generally straightens me right out. If it matters on a saw go OEM or used OEM unless it is not available. Good luck with your saw.

 

[Jungleman]

Hehe I ordered a 3 dollar plug this morning on ebay. That’s just temporary while I work on it

 

[Wonkydonkey]

I think you will be using the the decomp your already got,, once you get your new cylinder fitted.
They rarely go wrong, they may leak I little, sometimes a little valve seating paste cleans them up.

 

[drf256]

Crank and bearings look good. Personally I’d cap the impulse barb, fill the case with mineral spirits or mix, and rotate it a bunch of times to wash it out. Repeat the step a few times and dump after each one. Look for metal flecks as you rotate it.

Mineral spirits or mix won’t hurt the seals at all. Rotate a few times, look at the large end bearing a few times on each side. See is it’s cracked. All looks good. You’ll have to do a vac check when you’re assembled.

like Kev said, get a meteor piston and clean that jug up, it still looks good.

 

[Jungleman]

You may be correct wonky, I took it off and it seems to work fine when I push it.

Thanks for the tip Richard. I will definitely plan on cleaning it out with mineral spirits. On that note I had a question. I noticed a little dent around the crank(no idea what that's called but it's where the base of the cylinder is attached) where the rod may possibly have hit it and thought maybe that's what caused the problem? Take a look and tell me what you think.

 

[Wonkydonkey]

If I think what your referring to,, it’s not a problem

Edit add pic for reference

 

[Jungleman]

If I think what your referring to,, it’s not a problem

Edit add pic for reference
View attachment 217341

Yep that's what I was talking about. Just looked like the rod was resting right in that spot where the edge looks broken. Thanks.

Still cleaning the cylinder. I can only work on this project one night a week for a few hours so it's taking a while.

 

[Skinnyminnie]

When you took the piston off, did the wrist pin and bearing look ok?

 

[Mastermind]

Nice project.

 

[Jungleman]

When you took the piston off, did the wrist pin and bearing look ok?

Again, I've never done any work on pistons or cylinders or bearings so keep that in mind. When I pulled up or down on the rod there is zero play. It doesnt move at all. When i turned it left to right it had a little give but I'm talking 2 mm(I didnt measure i just eyeballing it). I think that's because it can slide left or right on the bearing. So to me it feels solid.

I only removed one of the piston clips and popped out the bar holding it in place. It was very snug and looks like I can re use it to be honest. I was thinking of maybe even re using it on the meteor piston I have coming since it's original OEM stihl part. It looks brand new.

I dont know all the proper terms for parts. I'm just simple farmer from the jungle

 

[Jungleman]

Nice project.

Thank you Sir! This saw was my first ever that I bought brand spanking new so it has sentimental value for me. I only used it for a year myself but it ran perfect and I loved it with my 36"bar.