Stihl 066 wise me up

[Cut4fun]

I have just read about B cylinder for a 066 and etc and wonder what the deal is with different pistons and cylinders for the 066 and weather they can be mismatched without squish problems etc.

(just read this in a auction)
you are looking at a used Stihl 066 , this a B jug.

I have almost every stihl IPL manual and service manual and dont see anything on this.

 

[THALL10326]

I have just read about B cylinder for a 066 and etc and wonder what the deal is with different pistons and cylinders for the 066 and weather they can be mismatched without squish problems etc.

(just read this in a auction)
you are looking at a used Stihl 066 , this a B jug.

I have almost every stihl IPL manual and service manual and dont see anything on this.

Interesting. The only two I see listed are the 1209's and the 1211's. I think the later had a different type or amount of coating on the cylinder walls. Don't see anything about a B cylinder..

 

[Cut4fun]

I have searched the net and have read about mixing the 066 p+c's and creating head slapper in the 066's. Just trying to figure it out and learn from it. before it happens to me in the future.
Here is the auction where B cyl is mentioned http://cgi.ebay.com/Stihl-066-cylin...ryZ85915QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[ShoerFast]

Just .02 cents worth from the hip?

But could the term "B" be used to categorize pistons and cylinder sets that are lighter to match a run of cranks that needed a lot more weight reduction to true up?

Weight matching is used a lot in manufacturing, and the reason the info may not have been distributed everywhere, as just a few markets or zones would have received "B" balanced components?

 

[Cut4fun]

I was reading where a cly and mixed matched piston created a head slap and then another cylinder and piston was used on the same saw and the squish was perfect. So i havent a clue, but am trying to figure it out.
Also read where a aftermarket cyl was used with a stihl piston and got a head slapper. So something is up, but i bet 04 knows something on this and maybe the Lake.


Dean you know anything on this?

 

[Trigger-Time]

The "B"

Could this be the "B" cylinder........off late 2000 066

Sorry I was wrong.....Its off a 1999 066

 

[ShoerFast]

I was reading where a cly and mixed matched piston created a head slap and then another cylinder and piston was used on the same saw and the squish was perfect. So i havent a clue, but am trying to figure it out.
Also read where a aftermarket cyl was used with a stihl piston and got a head slapper. So something is up, but i bet 04 knows something on this and maybe the Lake.

Installing an AIP Pistion bought me a little better squish over the stock pistion that came out. Brought it from .024 - .020 , not a lot, but I'm good with that.

 

[Cut4fun]

I just figured if there is something to this, that it would be better to figure it out now then to find out the hard way. Thanks for all the input and shots from the hip.

 

[scottr]

Kevin , I remember reading about A and B cylinders in the Chainsaw Service Manual . Years ago I saw precision parts with A tolerances and B tolerances . I believe that some manufacturers use different methods of not scrapping a precision part because it is slightly out of tolerance . Maybe that was the birth of the chrome plated PP cylinder .

 

[Trigger-Time]

I just put a new crank in the 1999 066. I was not sure how it would
turn out so I used the cylinder off the 2000 066 and piston from
the 1999 066. Out side of cylinder, at base dose look different.
I turned it over by hand, it did'nt hit top of cylinder. Reason
for putting the 2000 cylinder on, is it has very, very slight scoring.....
if I was going to mess something up it mite as well be my worst
cylinder.

I hope I'm not about to find out something the..........Hard Way!

All the IPL's I have show the same piston part number....I do know
that they beefed up the cylinder base, went to 6mm X 25mm bolts
from the 5mm X 20mm bolts

 

[Cut4fun]

Kevin , I remember reading about A and B cylinders in the Chainsaw Service Manual .

Scott in this one? If so, I will try and find it too.
http://rds.yahoo.com/_ylt=A9iby4BFN...//www.cutterschoice.com/enewsletter/10034.jpg

 

[scottr]

Yes , that's the same service manual .

 

[Trigger-Time]

Pic of the cylinder bases....right is cylinder with the "B" 1999,
left is off 2000 model........could have been changed before
I bought the saws.............Go put the muffler back on now

 

[Cut4fun]

Pic of the cylinder bases....right is cylinder with the "B" 1999,
left is off 2000 model........could have been changed before
I bought the saws.............Go put the muffler back on now

Is the distance from the bottom of the cly to the top where the piston squish measured the same distance on both the cyl's pictured?

 

[Trigger-Time]

Is the distance from the bottom of the cly to the top where the piston squish measured the same distance on both the cyl's pictured?

I don't know............I did'nt think about any of this until I seen
this thread.........just thought they would interchange......I'm
keeping my fingers crossed

 

[Lakeside53]

Too much guessing going on... Don't worry about your squish.

It just the bore size as are result of QA. Tooling wears so there is no one "prefect" size. Stihl has A and B cylinders. Piston are also graded as such. All replacement pistons are AB - can be use in A or B cylinders... Look on the top of the Stihl pro pistons.

 

[Cut4fun]

so Lake what would create the head slapper with a 066 running a aftermarket cyl and a stihl piston, then put on a used stihl cyl and another switched to another stihl piston and it worked? So there is know differences in pin locations etc.

Now what if a 460BB aftermarket piston got slipped into a aftermarket 066 cyl? I read where they are both 52mm but the pin location is different.

I am just trying to learn what to get so i dont end up with a mixed matched set that will not work in the long run.

 

[Lakeside53]

Hard to say.. Maybe your after market cylinder is just not made to the same specs or QC as Stihl. Send it back and ask for another. The squish zone is affected by the machining of the cylinder height relative to the base etc etc. The factory squish has plenty of tolerance for piston crown <> pin location machining variations (tiny).

Slapping on one edge of the piston can also be due to excessive wear on the piston skirt. Are we talking new or used pistons?.

Did you use an OEM gasket (rubber coated steel, 0.5mm) or did you use the after market paper gasket? The 066 has tight squish, so you wouldn't want to loose any in the compressed gasket.

Can't answer your question about the 046BB piston...

You won't find an OEM cylinder/piston combination that won't work on an 066, but you do need to be careful if you are buying NOS pistons. After market - you should always check squish and piston fit.

 

[Cut4fun]

, but you do need to be careful if you are buying NOS pistons.
Aftermarket - you should always check swish and piston fit.

Lake I have just been reading this stuff on different homeowner forums as a lurker only, So I am just picking up bits of info and only can pass on and question what i have read. But thanks for the experienced answers.

Also why do I have to worry about NOS pistons, I thought that meant New Old Stock?

 

[Lakeside53]

Some NOS pistons are from cylinder/pistons sets sold as a set. They may be marked A or B, not AB. I can't remember which is smaller (piston)... but I think it's the B.


And of course, swish is always great, but SQUISH is to be checked