066 Rebuild, Port Job etc

[Deets066]

I use citrus degreaser, works better than anything I've used yet

 

[Brewz]

Will give it a try.

Any ideas on the carbon buildup on the bottom of the piston?

 

[Moparmyway]

Will give it a try.

Any ideas on the carbon buildup on the bottom of the piston?

Heat

I believe that heat from the crown area is dissipated to the underside, and some of the fuel/oil mix gets burned by it. If someone were to look at all things .......... I believe they would see a pattern of the buildup being in the hottest spots, not necessarily transferr inversion

It could be transferr inversion, but at speeds over 10,000 rpm while cutting, I believe the inertia of the incoming charge would win the battle, .......................... my opinion and $0.50 wont get you a cup of coffee

 

[jmssaws]

I'm still trying to understand transfer back flow,I've had a 1000 saws apart and have never seen carbon built up in the transfers, obviously it can happen but in my mind something has to be wrong for it to happen.

 

[Definitive Dave]

Inspect the red light wire harness closely for any weak, worn or kinked spots. Intermittent short/fault conditions destroyed many of the red light coils and they are long nla.
066 is a thing of brauty

 

[jmssaws]

I'm still trying to understand transfer back flow,I've had a 1000 saws apart and have never seen carbon built up in the transfers, obviously it can happen but in my mind something has to be wrong for it to happen.

Wrong thread. Lol

 

[Moparmyway]

Wrong thread. Lol

Actually, it goes right along with how/where this thread blossomed

 

[Brewz]

Inspect the red light wire harness closely for any weak, worn or kinked spots. Intermittent short/fault conditions destroyed many of the red light coils and they are long nla.
066 is a thing of brauty

How exactly is the red light supposed to operate?
When I ran the saw up, I let it warm up and then gave a few short piss revs with bar and chain attached.

The red light kind of flickered randomly at WOT

I really want to preserve this thing so I shut it down and will leave it till it has been checked over.

How should the red light behave if working correctly ?

 

[jmssaws]

It's working properly. It will only come on at wfo

 

[huskihl]

I think it comes on when max rpm is achieved

 

[Definitive Dave]

According to what an old dude told me
you turn the high side pig rich and rev to WOT then lean till the light blinks steadily, stop leaning it is now perfectly in tune
Take that with a grain of salt I have never seen it in print in Stihl literature and believe me I have looked, lots of references to "assisting in obtaining proper tuning easily" but no step by step
Dave

 

[jmssaws]

Mine works properly at 13000 but I switched the coil out for the unlimited one

 

[Definitive Dave]

supposedly it can somehow gauge mix vs. revs vs. air flow or some such marketing mumbo jumbo
The idea was to make it easy for PNW loggers who work at vastly varying elevations without hearing protection to easily tune the saw a couple of times a day.
Of course crusty old logger types don't want no stinkin blinkin light tellin em what to do so they replaced them with standard coils and then you take the wiring issues that burned up a bunch of the red light coils that were a little fragile to start with and that is why not many survived
Dave

 

[Definitive Dave]

066 red light specified at by Stihl at 32:1 remember

 

[Brewz]

Haha, fragile electronics in a chainsaw that broke a lot....... Glad they haven't gone down that road again!

I got a few hours in the garage this afternoon to start getting an 066 built.

Cleaned everything......... boring

Warmed up the bearings and slid them onto the crank shafts
Tapped the alignment pins into the flywheel half of the case so they were just poking out a bit.
Heated up the flywheel half of the case and slid it onto the bearing.
I applied a very thin layer of motoseal 2 to the crank gasket surface and sat the gasket in place. I then applied another thin layer of motoseal 2 to the top of the gasket.
Heated up the other half of the case and slid it down over the bearing until it hit the alignment pins. This left me with a 3mm gap.
I assembled it this way because when pulling the 2 halves together with screws, it is pushing against the locating bearing on the flywheel side, which then sets the clutch side bearing to the correct position when the 2 halves are pulled down tight.
Tapped in the oil seals with sockets that pushed the outer edge of the seal. Pre oiled all seals, seal surfaces and bearings.
After the clutch side was clamped down tight, It took a tap on the flywheel side shaft with a nylon hammer to center the crank and relieve all the pressure off the bearings.
It then spun smoothly and freely, with the entire assembly happening without having to hit it with a hammer.

Bashing it together with a hammer just damages the bearings. It leaves little tiny dint's that are like a small hole in the road. The more it gets run over, the bigger it gets and you end up with premature bearing failure.
I cleaned up the OEM piston and removed all the little casting lips in the port windows, smoothing them out.
Fitted the piston up with a new small end bearing on the original Stihl wrist pin which is much lighter than the after market one.
Fitted a new Hyway gasket and bolted down the jug, checked squish at 4 points and got 0.019 to 0.021 so I will run it at that.
Fitted new Caber rings.
Thin smear of Motoseal 2 on the case flange, then bolted down the jug.

Cracked a cold beer to celibate.

From here on it it's just a jigsaw puzzle.
Fitted new oil line and pump seal ring.
New impulse line.
New clutch and sprocket
All new AV rubbers
New spark plug.

I got it to this stage, just about ready to fire up, but had to go out to dinner with the wife and some friends.
Should get it finished off tomorrow morning



It is starting to look like a saw again.
It was upsetting looking at 2 of them as a filthy jigsaw puzzle all over the bench.

Only problem I hit is that the thread is stripped in one of the top cover holes.
I am thinking of filling the hole with JB Weld and re drilling and tapping it.

 

[Deets066]

I use time serts to fix any striped holes on my saws. You have to buy the kit to do one hole, but at least you have it for future use then

 

[Brewz]

Yeah I thought about something like that but I dont have a need to fix many stripped holes. I only work on my own saws and I know how to tension a screw.

It is only holding down a plastic cover so some JB Weld or Devcon will do the trick.
I might actually run a 6mm tap through the hole first to get a good hold for the putty.

But that can wait till after I fire it up and smoke up my garage

 

[Brewz]

Did the 066 red lights come with a decomp at any stage?

 

[Definitive Dave]

I am pretty darn sure they did not but we can check the tech bulletins to see when the new ignition and decomp were introduced

Edit: looks like the decomp valve was introduced about a year after switch away from red light

 

[Brewz]

Ah ok
There are a couple red lights that have come up for sale but they have decomp jugs and plastics