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

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I used a whole quart of 927 in a 395 milling in a couple days. I guess it got hot enough to not cause a mess inside. Seems the milling saws don't have deposits like a firewood saw.
My 250r's always had a black gooey tailpipe with 927 ,but i never had an engine fail with it ,jetting was perfect also so it was not too rich
 
- special thanks to Trx250r180 for providing some H1R.

- Method (cuz someone will ask)...

1. start with 50:1 stihl ultra in tank + bar + used chain.
2. make some cuts to warm up saw
3. take bar off, clean grooves in bar, put new .404 RS chain on.
4. start saw, check tension, retension.
5. clean air filter, top off 50:1 gas, top off oil. start saw
6. do cotton wood test cut, turn off saw, hurriedly grab camera and thermo, take temps
7. restart saw to keep warm. grab camera, thermo, running saw...walk over to other log.
8. do 2nd cut, turn off saw, hurriedly grab camera and thermo take temps.

9. now dump out 50:1 gas completely back into gas can
10. fill up with 40:1 gas
11. do cuts with old chain to get 40:1 gas into the system.
12. shut off saw, clean air filter, top off 40:1 gas, Top off oil.
13. take old chain off, take bar off, clean bar grooves, put on new chain for 40:1 test cut.
14. start saw, check tension, retension, start saw do 40:1 cuts....repeat repeat repeat. Every test was done exactly like the above.








few things...

- not what I expected!

- Both Stihl 50:1 & 40:1, seem to start off cooler (after 1 cut) , but then gets approx 10-15 F hotter than belray 50:1 and 42:1 on the 2nd cuts. While the belray 50:1 and 42:1 seem to get to temp faster but basically it stays at that temp. I like this about belray.

- I'd have to say based on the #s 32:1 just doesn't seem to work as good in a stock saw. Maybe it works better in a ported saw because of the higher compression? But a drop of 3-4 secs vs 42:1 and temps creeping up, that's pretty clear if you ask me. As to Why it worked out this way? I don't know...there is a happy medium of oil and gas in every 2 cycle and for this particular saw, 32:1 H1R isn't it!. Maybe the 661 was designed around 50:1?

- On the 2nd cut with the belray 50:1 I had a good 3 second hang up so that is why I put 32.8. So it appears that belray 50:1 and stihl 50:1 were the fastest. But I'd take the belray (even though I think it smells! lol). Based on what I've read and the specs of H1R vs Stihl ultra, I have little doubt that the Belray wouldn't provide better lube/maintaining the oil film.

- The 40:1 Stihl was clearly slower but ran same temps.

- Based on the results -

I'm thinking Belray H1R 45:1 would be interesting to try out. Maybe Stihl 50:1 vs belray 50:1 vs belray 45:1 with more cuts. Stihl just to compare. I'm sold on the belray. Question for me is the ratio. 45:1 looks like a happy medium and you can split the bottle in 3 equal parts (125ml/4.25oz) and it make 45:1 = 1.5 gal.


Here are the numbers laid out.

98hc34.jpg
 
two questions here: is stihl ultra not all it is hyped up to be? what about just running moto-mix all time? we sell that stuff, it seems, by the pallet load these days. i can get a heck of a deal on the 1 gallon cans. i had always ran ultra at 40:1, maybe motomix is better?
 
two questions here: is stihl ultra not all it is hyped up to be? what about just running moto-mix all time? we sell that stuff, it seems, by the pallet load these days. i can get a heck of a deal on the 1 gallon cans. i had always ran ultra at 40:1, maybe motomix is better?

when in doubt, test it out!
 
never had an issue with ultra @ 40:1. motomix would be nice though, no mixing. i usually run a little through my edger and blowers with i am done with them for the winter. always just run saws dry to store them.
 
Thanks for taking the time to do the testing.

I've always felt that the lighter ratio oil mixes had more "snap." But having a heavier oil content ensures the saws longevity. I'm sticking with 42:1. Never had a failure on most all ported saws yet.
 
Thanks for taking the time to do the testing.

I've always felt that the lighter ratio oil mixes had more "snap." But having a heavier oil content ensures the saws longevity. I'm sticking with 42:1. Never had a failure on most all ported saws yet.


I wouldn't argue with that at all. Ported saw = more compression. After I explained the compression differences between the ported and stock saws...ie. like 170 vs 200+. he said he'd opt for the 42:1 in the stock saw.

It certainly would be interesting to test 32:1 vs 40-42:1 in a ported saw.
 
I put probably 100 tanks of fuel through a 346 i had that was ported at 50:1 and nothin ever went wrong , and the dude i sold it to still uses it quite a bit....if it wasnt for this internet stuff i would've never switched..

Hell the Mexican's i work with just buy the ****** no name 2 stroke oil at the gas station in the morning. I don't even know if they measure anything they just fill the can and pour in the oil and they're off.......never have any problems.
 
Definitely would agree with more snap like pulling over a saw that you just put together with 2 stroke oil, its got extra drag same principle although exaggerated, I would think. I think single rings are snapier too as there is less surface in contact with the walls.
 
Doesn't the richer oil mixture than 2% cause the piston top and the spark plug dark as a coal cellar, and the muffler outlet dripping of oil?
Does the AutoTune/M-Tronic minimizes the carbon build-up, even with oil mixtures at 1:40 & 1:33?
 
Again thanks for taking the time, and putting in the effort. The result are interesting, but by no means definitive. I expected a slight increase in temperature, but not a noticeable difference in power. My question is how quickly or accurately the system adjusted fuel flow?

As we knew going into this they're would be many uncontrolled variables. Nevertheless excellent test!!
 
Since oil molecules are thicker and less volatile than fuel molecules would it be possible that an engine would have more resistance past a certain point of PPM (parts per million) of safe effectiveness of lubrication that the oil actually becomes a hindrance to revolutions per minute (rpm)?

I remember seeing some performance guys finding the sweet spot of oil level within their engines so that the crankshafts, connecting rods and bearings were just in the oil enough so as not to have to spin through any more resistance than necessary. And that usually was at or below the add mark on the dipstick. And yes, they made more power and were faster. Oil past a certain point in volume becomes resistance.

Could it be possible that because a two strokes crankcase volume is so small the extra oil becomes indeed a resistance much quicker than one would suspect? Fuel on the other hand is very combustible and is searching constantly for a way to exit an engine, always drawn to the highest heat or flame. The combustion chamber. Are the molecules of fuel actually the catalyst that carries the oil to be combusted as long as the weight isn't too great? Or PPM too high (oil ratio)?

And one more thought, does an oil, like Belray, that has the greatest ability to adhere to metal produce the most resistance to travel with fuel to combust? If that oil is so effective in lubrication over all the other oils then shouldn't the ratio of the best lubricating oil actually be higher than the lesser oils?

So, in my simple mind too much oil provides superior protection. Too much oil also can drop H.P. And we know what happens when you use not enough oil. I also know that an engine translates it's "sweet spot" to the operator, as least to me, as it will feel sluggish rich and very tight when leaned. The Magic is finding the perfect middle, leaning toward the protection side of the chainsaw or engine for longevity without loosing HP. At least this has worked for me.

Since I am not a Pro by any stretch and cut firewood and goonies for fun I really don't know much as this is a hobby. But I'll tell you what, when I do get to play I sure want things to run as perfect as possible!

Other than being too lean of course, there is no right or wrong answer, just like the question "what is the right chainsaw for me?" It is all about personal preference and what works for you :)
 
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