50:1 vs 40:1

[Slamm]

There is some point where more oil isn't doing the saw anygood as far as lubrication. Provided there is enough oil sloshing around the crank and rings and bearings and such, more isn't going to save an improperly tuned saw. I know that Amsoil Saber at 50:1 provides a coating of blue oil all over the piston and crank to the point that no experienced human could think that more is needed, as it is everywhere and it is thick.

I'm pretty sure it can be easily argued with facts and shear volume of high hour saws and their users and manufactures that spec out 50:1 will provided plenty of lube for the saw to last a good long time. After that its just up to variables in how the operator abuses the saw.

That leaves the argument of more oil producing more power through better ring seal. Those "Studies" do show increased power a lower ratios 20:1 and 12:1, so forth, but are those minor power increases even felt in a typical work saw??????

I don't know, have never checked it out, but I seriously doubt it. I would say more benefits would come from better tuning to the weather, than specific oil ratios when trying to increase power.

Thats why these oil threads are so dumb, the differences between crap oil and the finest synthetic are nill. The differences in power and protection between 50:1 and 20:1 are nill.

My take on it,

Sam

 

[Team FAST]

The point of the RC engine testing article - which is applicable to chainsaws - is that harder working/higher ouput/high performance engines turning high RPMS require a richer oil mixture.

On kart racing engines, we found more horsepower as the amount of oil was increased...to a point. On the dyno, we found that increasing oil reduced motoring friction, and also improved ring sealing. It also allowed the main rod bearing to run cooler, enabling high sustained power output at higher rpms.

I run 32:1 or even richer. 4 to 4.5 oz/gallon I use Redline synthetic two stroke racing oil. Or Maxima 927 Castor.

Yes, more smoke. Its a two stroke!

Tastes great! Less Filling!

 

[edisto]

You can think what ever the hell you want, I could careless what you think. You seem to not want to except facts. You are doing a good deed by keeping parts people and mechanics employed I'm guessing or do you dispute their knowledge and training too?

You are right...I don't like to except facts. I do accept them though. I also do keep some parts people busy...no mechanics though.

Well old knowledge isn't current for most things now, so the relevance of 30 year old knowledge doesn't really hold water with today's innovations.

Oils certainly have gotten better...that's why you can run 50:1 or 40:1 in an old saw.

Give him a copy of the study if you are so confident.

See that? I can respond to 3 messages with 1. Keeps things neater. Unlike, say, responding to the same one 3 times. Next time collect your thoughts, and then post.

The information is available. Just a matter of looking.

Here's a clue though, Timberwolf kept track of exhaust and cylinder temps while varying mix ratios. No noticeable power increase, but here are regression lines I generated for the data he posted:

 

[aussie2]

I'm sorry, but doesn't sound like you have a grasp of lean/rich vs extra oil in the mix. A lean saw will certainly toast a saw. But a saw piston is cooled by the intake charge entering the cylinder: 50:1 oil provides plenty of lubrication.

not over here mate one hot day and too less of oil and you willl be looking for your warranty pappers,fair enough you can run 50:1 but that depends on what cutting your doing and the conditions.
if your cutting firewood cuters here normally cut around 30 tone per day per saw, i couldnt see a saw cutting that on 50:1 and lasting ??? it just doesnt happen they are running that hot the fuel is vapourizing.
if the saws are not working hard it may not matter .

 

[Andyshine77]

Amsoil Saber is a very thick concentrated oil and I'm sure it works great at 50:1, but most oils are thinned out with solvents. Fact is a saturation point where more oil does more harm than good does exist.

All I'm going to say in this thread, is pretty much what I've said many times before. I've been in engines with mix ratios from 100:1 to 32:1 and I will continue to run my saws at 32:1.

 

[Johny Utah]

The point of the RC engine testing article - which is applicable to chainsaws - is that harder working/higher ouput/high performance engines turning high RPMS require a richer oil mixture.

On kart racing engines, we found more horsepower as the amount of oil was increased...to a point. On the dyno, we found that increasing oil reduced motoring friction, and also improved ring sealing. It also allowed the main rod bearing to run cooler, enabling high sustained power output at higher rpms.

I run 32:1 or even richer. 4 to 4.5 oz/gallon I use Redline synthetic two stroke racing oil. Or Maxima 927 Castor.

Yes, more smoke. Its a two stroke!

Tastes great! Less Filling!

That is some good info, I was not aware of that. The oil didn't seal the rings for to long I would think before it burned off? Did you guys do any compression testing on cold and hot engines using the different oil ratios?

 

[Johny Utah]

You are right...I don't like to except facts. I do accept them though. I also do keep some parts people busy...no mechanics though.



Oils certainly have gotten better...that's why you can run 50:1 or 40:1 in an old saw.



See that? I can respond to 3 messages with 1. Keeps things neater. Unlike, say, responding to the same one 3 times. Next time collect your thoughts, and then post.

The information is available. Just a matter of looking.

Here's a clue though, Timberwolf kept track of exhaust and cylinder temps while varying mix ratios. No noticeable power increase, but here are regression lines I generated for the data he posted:

I'm not very good with graphs but I think what it shows is the more oil the more heat, is that correct?

 

[Team FAST]

That is some good info, I was not aware of that. The oil didn't seal the rings for to long I would think before it burned off? Did you guys do any compression testing on cold and hot engines using the different oil ratios?

No we never did anything silly like that. Compression testing using a pressure gage is something I think only chainsaw guys do

 

[one.man.band]

40:1 vs. 50:1 ......curiously the same thread name from a few months ago back:

http://www.arboristsite.com/chainsaw/182877.htm

 

[Slamm]

No we never did anything silly like that. Compression testing using a pressure gage is something I think only chainsaw guys do

Once it is explained it does seem a little silly.

Sam

 

[edisto]

I'm not very good with graphs but I think what it shows is the more oil the more heat, is that correct?

Not in the exhaust...

 

[Slamm]

Not in the exhaust...

???? Sure looks like that graphs shows everything is getting hotter with the use of more oil in the gas.

That said, I think I remember that he didn't retune the saws for the increased oil ratio's and hence there was less cooling fuel in the mix.

Sam

 

[edisto]

???? Sure looks like that graphs shows everything is getting hotter with the use of more oil in the gas.

That said, I think I remember that he didn't retune the saws for the increased oil ratio's and hence there was less cooling fuel in the mix.

Sam

Those are trend lines...and the slopes for the exhaust change don't differ from zero.

That's not the point though, the point is that the big change seen in the cylinder temperature is not reflected in the exhaust temperature, i.e., it isn't a matter of overall temperature increasing.

 

[one.man.band]

Not in the exhaust...

whole thread here:

http://www.arboristsite.com/chainsaw/6222.htm

(edisto....... i wholeheartedly expected some kind of mathematical equation in your reply).

trend line is ok.......but would a linear regression be more accurate?

just trying to keep you honest.....
--OMB

 

[one.man.band]

The point of the RC engine testing article - which is applicable to chainsaws - is that harder working/higher ouput/high performance engines turning high RPMS require a richer oil mixture.

On kart racing engines, we found more horsepower as the amount of oil was increased...to a point. On the dyno, we found that increasing oil reduced motoring friction, and also improved ring sealing. It also allowed the main rod bearing to run cooler, enabling high sustained power output at higher rpms.

I run 32:1 or even richer. 4 to 4.5 oz/gallon I use Redline synthetic two stroke racing oil. Or Maxima 927 Castor.

Yes, more smoke. Its a two stroke!

Tastes great! Less Filling!

"rc oil torture test was test" ......actually, main point was to determine oil deposits of various oils and wear (if any).

this link below shows effect of oil migration through engine, which is more in agreement with your first sentence.

Tech Tips - Maxima Racing Usa - Overkill

 

[Jonsered2095]

http://www.arboristsite.com/chainsaw/136449.htm


But I'm not biased...:spam:

 

[Team FAST]

"rc oil torture test was test" ......actually, main point was to determine oil deposits of various oils and wear (if any).

this link below shows effect of oil migration through engine, which is more in agreement with your first sentence.

Tech Tips - Maxima Racing Usa - Overkill

I would say their findings makes my point exactly. One thing to keep in mind is that the duty cycle of a high RPM kart engine used on a roadracing course is WAY more than a chainsaw. We would spend about 85% or more of a lap on a ful sized road racing course at WOT.

Here's a clip of me on my CR-250 powered superkart at Mid-Ohio. Listen to the engine Peak RPMS were over 11,000 way more than the motocrosser turns on dirt.

<iframe width="420" height="315" src="http://www.youtube.com/embed/uwtxa_KIS94" frameborder="0" allowfullscreen></iframe>

 

[edisto]

trend line is ok.......but would a linear regression be more accurate?

just trying to keep you honest.....
--OMB

More informative, not more accurate. And redundant. How else do you think you generate trend lines for linear relationships?

 

[Jonsered2095]

I would say their findings makes my point exactly. One thing to keep in mind is that the duty cycle of a high RPM kart engine used on a roadracing course is WAY more than a chainsaw. We would spend about 85% or more of a lap on a ful sized road racing course at WOT.

Disagree with 85%. You have gears...

Great race though!:msp_smile:

 

[edisto]

http://www.arboristsite.com/chainsaw/136449.htm

That's the Jenning's article I was referring too.

Bell found the same thing. His interpretation was not just about improved ring sealing, but improved heat transfer from the piston to the cylinder. More heat into the cylinder, less heat into the charge in the crankcase.

Less heat into the charge in the crankcase, less expansion of the charge, more charge for the same volume.

That is why I found TW's data so interesting. More heat transferred to the cylinder wall would explain the rise in cylinder temp, without a similar increase in exhaust temp.