066 - rebuild?

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johnnychap

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Gday from Adelaide South Australia champions. Disclaimer - genuine newbie to chainsaw repairs but really keen to learn.

I’ve just purchased an 066 that was sold very cheap as ‘lost compression, needs rebuild’. Although I literally know nothing or how to really start, it was absolutely cheap enough to buy and give it a shot! I’ve started it, and it fires up as you’d expect but blows a fair bit of smoke so I’m assuming new rings as a minimum? I’ve checked for scoring on the piston just through the exhaust - no visible signs of damage.
I’m thinking I may have ended up with an ok buy here but wondering where to from here to really work out what I need to do..

thanks in advance!
 
Gday from Adelaide South Australia champions. Disclaimer - genuine newbie to chainsaw repairs but really keen to learn.

I’ve just purchased an 066 that was sold very cheap as ‘lost compression, needs rebuild’. Although I literally know nothing or how to really start, it was absolutely cheap enough to buy and give it a shot! I’ve started it, and it fires up as you’d expect but blows a fair bit of smoke so I’m assuming new rings as a minimum? I’ve checked for scoring on the piston just through the exhaust - no visible signs of damage.
I’m thinking I may have ended up with an ok buy here but wondering where to from here to really work out what I need to do..

thanks in advance!
If the P/C looks fine you shouldn't have to spend too much on it. Genuine Stihl in AU is about $900 for just those 2 parts (I was quoted for a 660).

Others will likely suggest vac test which is a good start, as well as a compression test. Starting is not a good test of compression for these big saws, I started my 660 and the piston was scored.

Pics will help, including of the piston / intake side of the cylinder with the piston lowered. Carb kit/new carb is probably a good idea unless it has been recently done.
 
If the P/C looks fine you shouldn't have to spend too much on it. Genuine Stihl in AU is about $900 for just those 2 parts (I was quoted for a 660).

Others will likely suggest vac test which is a good start, as well as a compression test. Starting is not a good test of compression for these big saws, I started my 660 and the piston was scored.

Pics will help, including of the piston / intake side of the cylinder with the piston lowered. Carb kit/new carb is probably a good idea unless it has been recently done.
Thanks mate I’ll put up some photos tonight. I can’t really get much info on what was done to the saw from the previous owner to be honest plus I’m not sure how much credence I would put on that anyway. Didn’t realise parts for rebuild were that much…
 
Genuine Stihl parts in AU are stupidly expensive. Users more knowledgeable than myself will be able to guide on what genuine parts you should use based on what the vac/compression test results are.

Plenty of good aftermarket:
P/C: Meteor
Rings: Caber
Carb: Walbro (depending on model of saw)
Plastic covers, AV rubbers: Farmertec have a big range for the 066, some people hate the company (Chinese) but anything A/M you see in AU is likely from them, just with a local supplier (Johno & Johno I have used before). You can also buy directly from them in China, but have to wait for shipping.
 
So to sum up- you live in Aussie- you found a cheap Stihl- you admit to being a novice........ hell in 18 months you will be a bloody expert saw mechanic!
Has happened here before!

You need to get yourself some basic tooling (most of which you likely already have) including a good T27 T handle driver and strip the saw down to remove the cylinder. Then you can see for real what is going on inside and check things like conrod big end bearings and such.
Might just need rings, might need a new top end........ or worse case scenario, new crank and new top end.
You wont really know until you are in there. Then you get to discover the wonderful retail prices of genuine Stihl parts out here in Australasia! Inside the engine, I would stick to and feel the 066 deserves genuine parts- aftermarket if bought in Aussie is likely to be Farmertec plus mark up and the quality just isn't really there when compared to genuine stuff. Same with the rubber componentry like intake manifolds and oil/fuel lines- aftermarket is cheap for a reason.
You have a nice saw, rebuild it with quality parts and it will be a very good saw for you for a long time yet. Cheap out and you will be posting a lot here asking how to fix each part you cheaped out on.
The copy cat stuff is fine for exterior plastics, clutch covers, mufflers, handles and stuff that does not control fuel mix, fuel air delivery, or the explosive burning of that mixture.
 
So to sum up- you live in Aussie- you found a cheap Stihl- you admit to being a novice........ hell in 18 months you will be a bloody expert saw mechanic!
Has happened here before!

You need to get yourself some basic tooling (most of which you likely already have) including a good T27 T handle driver and strip the saw down to remove the cylinder. Then you can see for real what is going on inside and check things like conrod big end bearings and such.
Might just need rings, might need a new top end........ or worse case scenario, new crank and new top end.
You wont really know until you are in there. Then you get to discover the wonderful retail prices of genuine Stihl parts out here in Australasia! Inside the engine, I would stick to and feel the 066 deserves genuine parts- aftermarket if bought in Aussie is likely to be Farmertec plus mark up and the quality just isn't really there when compared to genuine stuff. Same with the rubber componentry like intake manifolds and oil/fuel lines- aftermarket is cheap for a reason.
You have a nice saw, rebuild it with quality parts and it will be a very good saw for you for a long time yet. Cheap out and you will be posting a lot here asking how to fix each part you cheaped out on.
The copy cat stuff is fine for exterior plastics, clutch covers, mufflers, handles and stuff that does not control fuel mix, fuel air delivery, or the explosive burning of that mixture.
As I said, those more knowledgeable than me :D

Bob hits the nail on the head. Remember that in a 2 stroke at 14,000rpm, :chainsaw: the piston stops and reverses direction ~460 times per second. As he said, the internals you will want quality parts. Unless you are using it professionally, the 066 will last a lifetime.
 
Post pictures and look over saw with covers off to determine if it's OEM Stihl parts.

A Mityvac 8500 will let you do pres/vac testing. They are about $70-80 USD here. Try to do that before pulling cylinder. Those vacs come in handy for other things too, can bleed auto break lines, test auto engine componets......

Take off flywheel and clutch before pulling cylinder. Clutch is left hand thread, you should get a puller for flywheel. That will let you get at seals which you should change, and see them when doing pres/vac tests. A piece of rope in spark plug hole will work as a piston stop. Stihl gasket set comes with seals.

There were changes as they made the 066 which became the 660. Pictures will help us determine the vintage as would ser # located on case flat near where bar mounts. They changed the ignitions/flywheels, carbs, and crank/cases.

I attached a IPL and a 660 shop manual. The 660 manual will get you through most 066 stuff

I should get a 066 shop manual for myself. If anybody's got one handy?
 

Attachments

  • Stihl 066 IPL new.pdf
    2.3 MB · Views: 6
  • stihl 660 shop manual.pdf
    4.7 MB · Views: 6
Post pictures and look over saw with covers off to determine if it's OEM Stihl parts.

A Mityvac 8500 will let you do pres/vac testing. They are about $70-80 USD here. Try to do that before pulling cylinder. Those vacs come in handy for other things too, can bleed auto break lines, test auto engine componets......

Take off flywheel and clutch before pulling cylinder. Clutch is left hand thread, you should get a puller for flywheel. That will let you get at seals which you should change, and see them when doing pres/vac tests. A piece of rope in spark plug hole will work as a piston stop. Stihl gasket set comes with seals.

There were changes as they made the 066 which became the 660. Pictures will help us determine the vintage as would ser # located on case flat near where bar mounts. They changed the ignitions/flywheels, carbs, and crank/cases.

I attached a IPL and a 660 shop manual. The 660 manual will get you through most 066 stuff

I should get a 066 shop manual for myself. If anybody's got one handy?

Agree 100%, seals and gaskets are a bare minimum with any secondhand new to you saw- fairly cheap and fairly easily replaced.
With the 066, just remember to place the case to cylinder gasket over the conrod before fitting the piston- or at the very least before fitting the piston rings. If you try to force the metallic gasket over the piston with the rings in place- you CAN break a ring...... ask me how I know!

The 8500 Mityvac is likely to set him back about $200 of his Australian dollars- just like Stihl parts- genuine Mityvacs are kind of expensive over here!
 
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