Johnsred cs2166 down

[awful knawful]

My contractor bud brought his 2166 in for a no start condition.
No compression.
Anyway, dealer wants $600 to fix, so I ended up with it.
Already torn down, this is what I found. Used hydrochloric acid, Emery cloth and honing stone. Still feel with my finger, but nail doesn't catch.
Broken skirt, signs of seizure on exhaust side, top of piston shows good fuel not lean.
Experts with insight. Piston and good? Top end kit? Cold seize?

 

[huskihl]

Check the case bearings. See if the crank has any play on either side

 

[Woodslasher]

I'm not sure what caused the piston to begin melting, but here's what the Stihl service book says:

 

[huskihl]

I'm not sure what caused the piston to begin melting, but here's what the Stihl service book says:
View attachment 927215

See? Even Stihl knows their oil sucks

 

[awful knawful]

Only scoring on exhaust side. Crank is smooth.
I don't think lack of lube or air leak.

Just skirt failure? Or as posted above, carbon build up at exhaust?

Thinking of slapping a cross top end on it and let it rip. It probably cuts 10-15 cords a year for firewood and 10-20 trees as part of contracting business.

 

[huskihl]

I’d pop the seals out and have a look at the bearings

 

[awful knawful]

Did some measuring with my vernier caliper.
Piston top 1.957"
Piston bottom 1.949"

Cylinder 1.967 - 1.970"

Skirt thickness exhaust 0.024"
Skirt thickness intake0.043"

Piston has alot of slop in the cylinder. Is it a simple case of a worn out piston? Minimum 0.010" clearance, max 0.021".

What's a acceptable piston to wall clearance?

 

[huskihl]

Did some measuring with my vernier caliper.
Piston top 1.957"
Piston bottom 1.949"

Cylinder 1.967 - 1.970"

Skirt thickness exhaust 0.024"
Skirt thickness intake0.043"

Piston has alot of slop in the cylinder. Is it a simple case of a worn out piston? Minimum 0.010" clearance, max 0.021".

What's a acceptable piston to wall clearance?

.0015” - .004” skirt clearance

 

[awful knawful]

.0015” - .004” skirt clearance

So .010 is huge.......

 

[huskihl]

So .010 is huge.......

Yes

 

[awful knawful]

Yes

Thank you.
Pretty sure I just found the problem.

 

[awful knawful]

Rocks in bore bad.

 

[awful knawful]

It runs!!

 

[awful knawful]

Well I went to tune the saw and it would run out of fuel. Take top off saw runs well. I found I routed the fuel line wrong ( I didn't disassemble saw, dealer did) and it was getting pinched by cover. Routed fuel line properly and it runs.

Tuned saw and cut a 18" spruce that had fallen in the gully behind my house.

Saw is strong. I've got a 268xp and this 2166 is all that.

Gave it back to my bud. Saw him today, they've run 5 tanks through it and it's running very well.

Hopefully it stays that way. Put a CROSS top end on it. I've got $194 into it vs the $600+ the dealership wanted.

Owner is very happy.

 

[Bob Hedgecutter]

Nice work, not sure Cross would have been my first port of call for a new top end- but if it works, it works!
So where did the rest of the piston skits chunks go? Do a loop around the ports?
Hope the crankcase was well flushed out while you had it apart? If the piston has gone up and down enough times to wear that far- the saw is possibly due main bearings and seals anyhow.

 

[awful knawful]

Nice work, not sure Cross would have been my first port of call for a new top end- but if it works, it works!
So where did the rest of the piston skits chunks go? Do a loop around the ports?
Hope the crankcase was well flushed out while you had it apart? If the piston has gone up and down enough times to wear that far- the saw is possibly due main bearings and seals anyhow.

Nothing in bottom end. Bearings are good. Looks to be quite a low hour saw.

 

[Bob Hedgecutter]

Nothing in bottom end. Bearings are good. Looks to be quite a low hour saw.

Okay, will take your word on it, I never pulled it apart to see.
But if it is low hour- what do you reckon cause the skirts to wear so much?

 

[awful knawful]

Okay, will take your word on it, I never pulled it apart to see.
But if it is low hour- what do you reckon cause the skirts to wear so much?

That's what I don't understand. Light on oil? Saw is in super shape. I doubt it had 50 hours on it.

 

[Bob Hedgecutter]

That's what I don't understand. Light on oil? Saw is in super shape. I doubt it had 50 hours on it.

Don't know, I do know I have never seen a piston wear that far in 50 hours and I know my old original from new (model release) 2159 is still pretty tidy looking outside, but has done a gazillion hours and wore a piston similar to the one you removed.
If your buddy bought it new, then you know the history- if he did not buy it new, any monkey could have been in there, fried a piston, cleaned it up a bit, found a well used secondhand piston, threw it in got it going and promptly sold it to your buddy?

 

[RED-85-Z51]

Cross is solid for me. I loaned out my 660 blue clone with a ported cross top end and let him rip on it for his business for a couple weeks with a 36" bar/chain...he put alot of mix thru it and ran it hard...i pulled the muffler off and its spotless

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