the great oil debate
- Thread starter SIRCHOPALOT
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I never said it was a decrease in gas volume. I merely pointed out the differance in oil content percentage wise. Of course I saw jetted properly will have the same amount of fuel running through the motor regardless of oil ratio. And FWIW a high numeric oil ratio certainly does not cause a HP increase. This was disproved long ago in a SAE paper authored by MAC that concluded more oil made more power up untill the point plug fouling became a issue. As I am sure you are well aware with your background in kart racing that with todays oils a 16:1 ratio isnt a problem.
Are you not listening? A change in oil ratio does not lead to less gas being introduced into the combustion chamber provided the saw is tuned as should be done daily.
bvaught
ArboristSite Operative
When I bought the saw a few months ago I ran what the book said 50:1. Then I found this site and started mixing a little richer 40:1 as a compromise. After reading this weblog I have decided the dumb hillbillies win, from here on out its 32:1 for me.
Blowdown1
ArboristSite Operative
OK VT, I'll make you a deal. Let's settle this once and for all. We are both here in VA so it should be easy. I will bet you a saw (brand new, of your choice) that your numbers are bullsh!t and mine are right. (and let me say that I am simply talking about the amounts pre-combustion, i.e. in the mix). Once the fuel mix gets into the combusion chamber then things are subject to jetting and other variables come into play.
Game? We'll have them corroborated by engineering proffessors so you won't feel a conspiracy is going on when you lose.
And I am not sh!ttin' you. Put your money where your mouth is
Game? We'll have them corroborated by engineering proffessors so you won't feel a conspiracy is going on when you lose.
And I am not sh!ttin' you. Put your money where your mouth is
Al Smith
Addicted to ArboristSite
Not a slam,but a point of observation .I work with young engineers on a daily basis.I've seen good ones,and bad ones,seen them come and go .Most young ones,think they know about everything under the sun,the older ones don't have that attitude.I have to,on occasion,show a select few,where the bear went in the woods,so to speak.Sometimes it takes several lessons .I don't make a habit of slamming people,and am not in this case.I have ,however ,seen tool and die makers that have forgotten more than most mechanical engineers will ever know.As far as electrical,I suppose I may fit into that position myself,on occasion.When you think about it,though,a person should pick up something after 35 yrs,don't you think? 
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Never did I say I know everything about chainsaw engines and never did I say I know all. Actualy I admited to being wrong and making mistakes if you really want to get into it. Bvaught, I am sorry my mistakes have killed my credability, I fully understand your point. Please make sure you clean out your exaust port more often with a 32:1 mix, the extra oil will cause buildup. And Blowdown1, if you would please check the arboristsite rules you will notice there are is at least one you have broken in this thread. I am out of this post and forum, GOOD BYE!!!
SIRCHOPALOT
ArboristSite Operative
bwalker said:
ben- I know that you understand this. and I misstated what you said. what you said and what he was thinking were two different things. I was not trying to correct you, but trying to make a point with the "engineer". sorry about the confusion.
SIRCHOPALOT
ArboristSite Operative
VTMechEng said:
oops- another one bites the dust.
There you go again making more ASSumptions. In almost every case a 32:1 motor will run cleaner than a 50:1 motor. A. Graham Bell went in to detail on why this is the case in his excellant book Two Stroke Tuners Handbook.
I have a 02 cr 500 based dirtbike in my garage thats been run at 32:1 since new and the exhaust port is spotless, as is the exhaust pipe and its on its original spark plug. I also have a 05 snowmobile with over 2k miles on it that runs at 20:1 thats on its original plugs. The exhaust valves where pulled at 2000 miles and they where spotless with the exception of two small spots on either side of the Rave valve. The spots where removed in about two seconds with a plastic putty knife. The exhaust ports themselves where bare metal.
here is a pic of a sled cylinder that had a ton of miles on it ran at 32:1.
Blowdown1
ArboristSite Operative
I guess I was a little heavy-handed. But boy I was really starting to get excited about a saw for a milling rig.
This kind of crap/misinformation needs to be delt with, Blowdown. I dont think you got nasty with him untill he started spouting off the fact that he was a engineer.....
SIRCHOPALOT
ArboristSite Operative
ben- I'm sure you know this, but just for the "engineers" sake. carbon buildup is from heat, or lack of it. if you retard the Ignition curve on a 2-stroke you can end up with very high exh temps, but there won't be any carbon in the exh port. If you have lots of carbon, it is usually because your air/fuel mixture is too rich making the temp too low. If you know how to jet, this is not a problem. I think that the fact that mr "engineer" doesn't understand this is the problem.
Thats true chopalot. Off course I had a motor one time that had a stinger diameter that was two small. In order to help it live during long pulls I ran the main jet way fat. Upon tear down there was no carbon anywhere in the motor.
Typicaly you are right though, in that low exhaust temps lead to deposits. A engine jetted sharp and set up right will run clean at any ratio with good oil.
Typicaly you are right though, in that low exhaust temps lead to deposits. A engine jetted sharp and set up right will run clean at any ratio with good oil.
jimbo1490
ArboristSite Guru
A. Graham Bell went in to detail on why this is the case in his excellant book Two Stroke Tuners Handbook.
A really great book! From its pages you can learn to build your own tuned expansion pipes, among many other things.
Jimbo
A really great book! From its pages you can learn to build your own tuned expansion pipes, among many other things.
Jimbo
SIRCHOPALOT
ArboristSite Operative
bwalker said:
yes, but by being so rich you were just washing everything. there has to be enough heat to actually burn the fuel
that's what we call it when it is very rich "wash"Yes, the piston was totaly washed. The funny thing is most motors would run like poo this rich, but this motor in particular ran really well. I infact took second place with it in the 800 open mod class. Pretty remarkable when you consider that I was running up against full mod 800cc triples with a 800cc twin with a stock pipe!
SIRCHOPALOT
ArboristSite Operative
thats when you can brag about how good you are!
SIRCHOPALOT
ArboristSite Operative
you were probably only rich on the top end. I bet it had some good meat in the bottom and middle of the band didn't it?
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