Stihl 066 Build (Split+Crank Bearings or Top End only?)

[Martinm210]

Howdy,

Starting on my first saw build project. I've done a few dirt bike top ends and full rebuilds and such so I do have a little experience with 2 strokes in general. I did buy an 066 repair manual and IPL on ebay, so I feel pretty good about knowing what's missing and how to go about taking things apart.

I have an MS290 I've been using to cut about 4 cords a year with over the past 5 years and had an itch to get something a little bigger. I almost bought a new MS460, but I wanted to spend less and decided on used. Stumbled across this parts saw I picked up for $200 on ebay and starting my journey. My hopes is to have a nicely well rebuilt saw for around $500 and gain some experience building while I'm at it.

My initial plan and thought was to split the case and replace the crank bearings and seals, but now that I've torn it down pretty well and washed out the case with WD-40 really well, the crank and bearings feel pretty good.

Here are a few pictures:

This is what I bought for parts to start with:
Took a bit of a gamble buying on ebay, but the price was right and I was looking for a project anyhow.

Pretty dirty, but it didn't look as used/worn as some others I had be looking at, so I thought it would be a good case.

Handle notes is a regular 066 model, not sure what else the numbers tell me here. Only thing I know is that is has a poly type flywheel which I think is the newer 066 model as opposed to the aluminum flywheel types which is one of the other case parts.

After tearing down what I could, this is the case. It cleaned up pretty nicely and by the looks of the paint, seems to be a pretty good shape.

And a better look at my question at hand:

I don't know for sure what the history of the saw was, but it appears the case was never split. The piston was scored pretty bad and the cylinder is missing.

I'm currently watching for some of my missing parts, but planned on buying many from Bailey's like the BB piston/Cylinder kit, Max-flow air filter, carb rebuild kit, clutch/drum, misc...etc. I did however also order the crank bearings and a few other parts from my Stihl dealer today. Little did I know the two bearings would cost $45 for one and $27 for the other:jawdrop: , over $120 worth of stihl parts. So I've got most of the parts on the way, but I would need to buy a flywheel puller and small HF press and make a few case splitting tools.

• Would you recommend splitting the case and replacing the crank bearings?
• Or should I just put a new top end BB kit in there (looking at one of Baileys BB kits)?
• How often do the needlecage in the cranks fail? It seems like if you split the case and replace the crank bearings you might as well replace the crank at the same time right?
• Any general tips for what to look for when making this decision?

Anyhow, having funopcorn: , just not sure it's necessary to split the case on this one . Any suggestions?

Thanks!
Martin

 

[nilzlofgren]

You probably should go with the BB kit. Why go through all that hassle of tearing it down, if there is nothing wrong. By the way, welcome to the site.

 

[Martinm210]

Thanks!

That's what I was leaning towards. I guess I just assumed worse case and that the crank/bearings/seals would be shot too.

I washed out the case really good with WD-40 and the bearings sound pretty smooth and no play that I can feel. The Crank/connecting rod needle bearings appear to be working smoothly and no flat spots that I can see.

I guess I'll make the bailey's order for the remaining top end parts and save these crank bearings for later. I do have another what appears to be good crank in the other parts saw I have here too.

Of coarse I'll have to look over that BB kit and consider a little mild port work, at least cleaning things up if nothing else..:greenchainsaw:

 

[Jacob J.]

Martin- a couple things on the big bore kit. You may need to notch the case a little bit to fit the piston, and the stock teflon-covered aluminum gasket won't work. You'll need to make a paper gasket or buy the 1mm paper gasket from a dealer and trim it. None of the factory gaskets are big enough to clear the BB piston.

If the main bearings feel tight and roll smooth, you may not need to replace them. Make sure your seals are good. The rod bearing rarely fails with correct fuel/oil mix and normal use, and your crank looks pretty good. I'd trust it.

I'm just over the hill from you near Grants Pass. In fact- I was just down in Keno the other day buying some vintage saws. I bought a couple antique saws from a guy there in K-falls earlier this year too over on Landers ave.- Fun stuff.

 

[bigbadbob]

I have a couple of 066 carcasses and thought to build a saw with them only to discover the clutch side bearing on both had slogged out the case.
So be sure and check for play between the case and bearing.

 

[Tzed250]

Thanks!

That's what I was leaning towards. I guess I just assumed worse case and that the crank/bearings/seals would be shot too.

I washed out the case really good with WD-40 and the bearings sound pretty smooth and no play that I can feel. The Crank/connecting rod needle bearings appear to be working smoothly and no flat spots that I can see.

I guess I'll make the bailey's order for the remaining top end parts and save these crank bearings for later. I do have another what appears to be good crank in the other parts saw I have here too.

Of coarse I'll have to look over that BB kit and consider a little mild port work, at least cleaning things up if nothing else..:greenchainsaw:

You need to be careful...if you washed out the cases with the seals in place then dirt may have washed between the bearings and the seals. This may cause bearing failure down the road.

 

[Martinm210]

Martin- a couple things on the big bore kit. You may need to notch the case a little bit to fit the piston, and the stock teflon-covered aluminum gasket won't work. You'll need to make a paper gasket or buy the 1mm paper gasket from a dealer and trim it. None of the factory gaskets are big enough to clear the BB piston.

If the main bearings feel tight and roll smooth, you may not need to replace them. Make sure your seals are good. The rod bearing rarely fails with correct fuel/oil mix and normal use, and your crank looks pretty good. I'd trust it.

I'm just over the hill from you near Grants Pass. In fact- I was just down in Keno the other day buying some vintage saws. I bought a couple antique saws from a guy there in K-falls earlier this year too over on Landers ave.- Fun stuff.

Thanks!
I'll plan on that and pick up some 1mm gasket material. I figured there would be a little work getting the aftermarket jug just right. I'm not planning to do any cutting for a few months, so I've got time to make things right.

I've got some new bearings on order, so if worst case they make more noise than expected running, I can always tear it down the rest of the way.

I have a couple of 066 carcasses and thought to build a saw with them only to discover the clutch side bearing on both had slogged out the case.
So be sure and check for play between the case and bearing.

Good to know, I'll watch for that. I really only intended to build one saw with the three I bought, but I see one of them has a really loose crank on one side that appears may be exactly what you've pointed out. I can't really tell if it's the bearing or case, but I may use them to practice tearing down on and investigate..

You need to be careful...if you washed out the cases with the seals in place then dirt may have washed between the bearings and the seals. This may cause bearing failure down the road.

I did hold the case up vertically while washing so the dirt and cleaner would flow out of the case, but I'll spend some time giving it a several more good cleanings, maybe mix up a heavy oil gas brew to wash it out with. I've still got some dirt bike gas to use up, should work great for cleaning.

Thanks for all the tips, time to order some new parts..:greenchainsaw:

 

[Lakeside53]

you'll need 0.5mm gasket material... 1mm is too thick -Jacob was saying it is all you can get from stihl. Surely your BB source has the right gasket, surely...

 

[Martinm210]

you'll need 0.5mm gasket material... 1mm is too thick -Jacob was saying it is all you can get from stihl. Surely your BB source has the right gasket, surely...

Thanks!,
I was looking to buy this woodsman pro BB kit:
http://www.baileysonline.com/itemdetail.asp?item=BBN+066&catID=385
There are a couple of other types on ebay, is there any particular favorite BB kit brands out there people like better?


The item description recommends their 066 kit, but no mention of the thickness:
http://www.baileysonline.com/itemdetail.asp?item=CRS+066&catID=104

I'll need the muffler and heat sheild out of the gasket set anyhow, so I'll order it and measure the thickness when it gets here.

My stihl IPL manual has two gaskets listed: A .5mm thickness part #1122 029 2306, and a 1mm thickness part #1122 029 2306. It just notes te 1mm thickness is for low compression.

Considering how expensive genuin stihl parts are, I think I'll wait until I measure the kit gasket, if it's too thick I'll order the .5mm or make one.

Thanks for all the help!
Martin

 

[Lakeside53]

The gasket kit is going to come with the rubber coated steel gasket - 0.5mm... which will not work with a BB.

 

[Martinm210]

The gasket kit is going to come with the rubber coated steel gasket - 0.5mm... which will not work with a BB.

Ok, thanks!

I'll make sure to get some .5mm paper gasket material too then.

 

[Lakeside53]

No need - your BB should come with a gasket - if not, tell them to send one...

 

[Martinm210]

No need - your BB should come with a gasket - if not, tell them to send one...

Even better..

Itching to go make that big bailey's order now..

 

[OilHead]

If you want to make that saw really come around check the squish with the thin gasket which is like .020 thick. Idealy we want a squish of .025 Machine off base as needed to correct. One note make sure your right to the edge of the piston .050 dia solder works fine. Put it in 2 different places & compair the readings. A dab of grease holds it in place. If by chance something was to happen during the sergery your ace in the hole is the fact that the paper gasket comes in at .045 . The next step it to set the pop off pressure of the carb at 19-20 psi. 13,400 rpm on final set after its broken in seems to be good on the one I did. Watch closely though as it brakes in it will want more fuel . & dont use synthetic oil to break it in .

 

[Martinm210]

If you want to make that saw really come around check the squish with the thin gasket which is like .020 thick. Idealy we want a squish of .025 Machine off base as needed to correct. One note make sure your right to the edge of the piston .050 dia solder works fine. Put it in 2 different places & compair the readings. A dab of grease holds it in place. If by chance something was to happen during the sergery your ace in the hole is the fact that the paper gasket comes in at .045 . The next step it to set the pop off pressure of the carb at 19-20 psi. 13,400 rpm on final set after its broken in seems to be good on the one I did. Watch closely though as it brakes in it will want more fuel . & dont use synthetic oil to break it in .

Awesome tips!, I will do that. I just happen to have a small mill/lathe combo in the garage that'll work just fine for that.

Any suggestions for porting on the BB jug? I was just thinking I would check the matches between intake/exhaust and clean up any casting flaws and maybe polish the exhaust port. Not sure about changing the actual ports though.

I also plan to take the new muffler I bought and dual port it nicely.

I only use stihl oil for my small engines, it's always served me well. Might need to look at picking up a tach for tuning too.

 

[OilHead]

Heres the mod to the carb. It should be pretty close I only cut off like 1/2 to 1 turn on the 066 . 19-20 psi is good . - - http://www.aerocorsair.com/id28.htm I highly recommend the factory DP cover as it has the screen & can be opened up quite a bit.

 

[Lakeside53]

I've never found the need to alter the pop-off on a stihl saw yet

 

[Martinm210]

Heres the mod to the carb. It should be pretty close I only cut off like 1/2 to 1 turn on the 066 . 19-20 psi is good . - - http://www.aerocorsair.com/id28.htm I highly recommend the factory DP cover as it has the screen & can be opened up quite a bit.

Thanks!

I'll check that too. I have a nice digital manometer that's good out to 25psi that'll work good for that.

I made a big order last night for most of my remaining parts, so more building will soon come..

I've mostly just been tearing down and clean parts so far...it's amazing how much oil and dirt can accumulate in a saw....must have lost 5 lbs on the saw already...lol!

 

[OilHead]

I've never found the need to alter the pop-off on a stihl saw yet

I highly recommend you try it. Combined with the increased compression of droping the jug you'll never settle for the lack luster performance of the stock configuration again.

 

[Ben Barnhart]

Sorry to hijack an extremely old thread but do you by chance still have the aluminum flywheel cases? Came to a dead end on my project due to cracked cases. Thank you