661 Oil Test 32:1 vs 40:1 vs 50:1 ?

[Hedgerow]

That's why I insisted that redbull660 remove a cylinder once. Exhaust port doesn't tell the whole story.

That's why I got a pic from under the piston...
It seemed very wet in that crank case.
Wanted everyone else to see what I was lookin at.

 

[cuttinties]

That's why I got a pic from under the piston...
It seemed very wet in that crank case.
Wanted everyone else to see what I was lookin at.

Looks pretty healthy to me.

 

[bwalker]

Then everyone that has a ported saw with a cut squish should be concerned with carbon buildup. Especially if they only have 0.020 clearance left!

The turbulence of the tighter squish doesn't allow carbon to build up that thick.

 

[Andyshine77]

FWIW.. Took Levi's 025 apart last week and got a crappy pic..
History:
Saw has been in use with a fixed jet carb for 2 years doing general limbing and wood cutting duty.
Maybe 50 tanks of fuel since we had it. Not one of the heavy users.
First year stihl ultra, then switched to Lucas this last year.
40:1
Nice pool of oil in bottom of pan, clean and wet bearings, just a tick of carbon on the crown mostly on exhaust side, and ring grooves clear.
Most of the machine marks are still evident on the skirts, 154psi comp.
Running fine, but Levi wanted to make a couple mods to it.

View attachment 427468

Maybe it's just the pic, but it looks like the skirt is polished to death??

 

[Andyshine77]

Sure seems quiet tonight.

 

[KG441c]

Site has been down for most folks

 

[Andyshine77]

Site has been down for most folks

Right around the time made that post, I couldn't log back on. The site has been quite unreliable lately.

 

[Moparmyway]

I agree, but most run way rich from what I can tell.

This might be intentional ............
Take my ported 066, for example
WAAAY rich by most standards, but WOT is 14,000 and studdering its so fat.

So some may limit max WOT rpm by intentionally running rich, which also has a benefit of producing lots of cool running torque, and extra oil for main bearings. Understanding fully that a leaner tune could produce more RPM ................ but choosing to limit RPM and keep cooler temps. I dont have spooge out the mufflers after a good workout, but it will be there if making smaller cuts.

Its not allways cut and dry, stumping aint as tough as milling, but it is definately tougher than cutting firewood.

 

[Moparmyway]

That washing is also washing oil of the cylinder walls. Liquid pre mix is. A terrible lubricant.

While I understand what you are saying, the evidence inside the saw tells me there is oil everywhere and no need for concerns about "washing" of anything

It's funny that you guys will argue for Yeats which 70cc saw is best, then tune so rich that any advantage goes out the window.

I have never argued on this, as its purely an opinionated answer IMHO

 

[bwalker]

While I understand what you are saying, the evidence inside the saw tells me there is oil everywhere and no need for concerns about "washing" O

Of course there is after the fuel evaporates from sitting.

 

[Moparmyway]

Of course there is after the fuel evaporates from sitting.

I have pulled the jug off while hot ............ same coating hot or cold.

If washing the walls were something of a concern, wouldnt there be evidence of it (scratches or galling) eithor on the cylinder walls or on the piston skirt ?

 

[bwalker]

I have pulled the jug off while hot ............ same coating hot or cold.

If washing the walls were something of a concern, wouldnt there be evidence of it (scratches or galling) eithor on the cylinder walls or on the piston skirt ?

Maybe, or maybe slight damage over time. The point being, IMO, running a saw excessively rich is a bad thing for a variety of reasons. In the near future it will be irrelevant as autotune, mtronic and the like take over.

 

[Moparmyway]

maybe slight damage over time.

Well, I will certainly keep my eyes peeled for any signs.

How about everyone else ................... anybody have any pics of too much oil damage from tuning too rich ?

 

[NWCoaster]

Well, I will certainly keep my eyes peeled for any signs.

How about everyone else ................... anybody have any pics of too much oil damage from tuning too rich ?

I agree that having a bit too much oil is better than not quite enough obviously. But at say 40:1 with a clean burning oil that does not inhibit combustion and power and is not running out the muffler, wouldn't that be better? To each his own, ( especially for reliability) , but some of the heavier high flashpoint oils seem a little excessive?

 

[Moparmyway]

I agree that having a bit too much oil is better than not quite enough obviously. But at say 40:1 with a clean burning oil that does not inhibit combustion and power and is not running out the muffler, wouldn't that be better?

For your saw, probably..................
For my ported 066 that got hot at least once, (and blued the big rod end) I will run 24:1 and keep her pig rich 4 stroking WOT 14,000. My main bearings have already been thanking me !

 

[NWCoaster]

For your saw, probably..................
For my ported 066 that got hot at least once, (and blued the big rod end) I will run 24:1 and keep her pig rich 4 stroking WOT 14,000. My main bearings have already been thanking me !

Ok, gotcha. Totally makes sense in that case, thanks for clarifying.

 

[Hedgerow]

Maybe it's just the pic, but it looks like the skirt is polished to death??

Reflection.. Machine marks still there.

Told you it was a crappy picture..

 

[blsnelling]

For my ported 066 that got hot at least once, (and blued the big rod end) I will run 24:1 and keep her pig rich 4 stroking WOT 14,000. My main bearings have already been thanking me !

I can't imagine any saw needing 24:1 and needing tuned rich like that. If so, it's a bandaid for something more serious. Tuning rich leaves all kinds of power on the table.

 

[bwalker]

I can't imagine any saw needing 24:1 and needing tuned rich like that. If so, it's a bandaid for something more serious. Tuning rich leaves all kinds of power on the table.

This.
OTOH I have used excess oil to prevent failure from poorly engineered piston rings on 800 cc Rotax twins. I ran the engine at 20:1 and never had a failure, while 3 friends with the same year and model all did. Anecdotal, but I believe the oil ratio I ran played a significant part.

 

[Mastermind]

Are y'all any closer to finding the perfect oil yet?