|
Matronics Email Lists Web Forum Interface to the Matronics Email Lists
|
View previous topic :: View next topic |
Author |
Message |
WhiskeyVictor36(at)aol.co Guest
|
Posted: Thu Apr 03, 2008 5:43 pm Post subject: 2 strokes |
|
|
In a message dated 4/3/2008 5:14:44 P.M. Eastern Daylight Time, donghe(at)one-eleven.net writes:
Quote: | With the saw and carb properly adjusted on the recommended 50:1 ratio fuel mix (remember adjustable jet carbs?) we would run the saw at full RPMS and let the CHT stabilize...then shut it off, dump the fuel and fill it from the next can...at 40: 1 and repeat...this run showed a higher CHT...then we would repeat and do it again with the 25:1..which showed even higher CHT. I can remember some of those old timers accusing us of trying to trick them...but after this demonstration most of them finally got it.
Generally we would then spend a half a day trying to explain the reasons this happens, which I wont go into here, but rest assured...MORE oil in the mix is NOT better.
Don G,
You probably know better than I, but my thinking is that the reason that more oil is not better, is because it makes the air/fuel mixture leaner. More oily yes. But more oil means there is less gas being mixed with the incoming air, thus a leaner mixture occurs, which can lead to higher EGT and the dreaded seizure.
By the way, I used to ride a Zundapp 2-stroke motorcycle back in the 1950's which called for a 20:1 ratio. And Yamaha TD-1 road racers of that same era used a 16:1 ratio. I guess better metals and oils are the reason for allowing 50:1 ratios nowadays.
Bill Varnes
Original Kolb FireStar
Audubon NJ
|
Planning your summer road trip? Check out AOL Travel Guides.
[quote][b]
| - The Matronics Kolb-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kolb-List |
|
|
|
Back to top |
|
|
Don G
Joined: 10 Jan 2006 Posts: 156 Location: Central Illinois
|
Posted: Thu Apr 03, 2008 6:13 pm Post subject: Re: 2 strokes |
|
|
Dana, yes sir, you understand it...and you bring another valid point. Entirely correct. another of many reasons.
And Bill You have it to...more is not better for several reasons.
And as previously mentioned... it make carbon because oil burns at with a much slower flame front..so it does not get all burned in one rev..leaving oil on the hot piston that continually builds up and just cooks.
So, in order of sequence the first thing bad that is the engine runs at a hotter temp than normal...
.then the carbon builds up on the piston and in the progresses to the ring grooves...
then the oil starts burning a varnish like brown on the sides of the piston, there by displacing the space for that ever important oil film....and pretty soon....seizure.... from too much oil in the fuel mix.
And just so you guys and gals get the perspective, back in those days I was working for the chainsaw company..(late 80's)..the component that had highest need for lubrication on those engines was the ball bearings on the crank...then the next was the wrist pin roller bearings....they needed much more lubrication than the piston skirt....we experimented back then with sealed bearings on the crank and ran very successfully on 150: 1 fuel oil mix and that was all the piston skirt needed.
When we changed to 50:1 it was because our bearing vendor brought us new bearings that needed less lubrication.
Coincidently....the same design technology era of the Rotax 2 cycle engines we fly behind....or in front of..... today
| - The Matronics Kolb-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kolb-List |
|
_________________ Don G.
Central Illinois
Kitfox IV Speedster
Luscombe 8A
RV9A |
|
Back to top |
|
|
knowvne(at)aol.com Guest
|
|
Back to top |
|
|
GeoR38
Joined: 25 Jan 2006 Posts: 60 Location: The Villages, fl
|
Posted: Fri Apr 04, 2008 7:39 pm Post subject: 2 strokes |
|
|
In a message dated 4/3/2008 5:14:44 P.M. Eastern Daylight Time, donghe(at)one-eleven.net writes:
Quote: | Generally we would then spend a half a day trying to explain the reasons this happens, which I wont go into here, but rest assured...MORE oil in the mix is NOT better.
If you want to split hairs, Since all manufacturers calculate a safety margin for recommended mix...a little less is actually safer then a little more...but stick with recommendations from the manufacturer.
We engineers that work for engine companies dont calculate these ratios haphazardly believe me, because for us, its a matter of dollars spent on warranty claims...and the reputation of our products.
--------
Don G.
Central Illinois
Kitfox IV Speedster
Luscombe 8A |
D
Planning your summer road trip? Check out AOL Travel Guides.
[quote][b]
| - The Matronics Kolb-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kolb-List |
|
_________________ George Randolph
Firestar driver, The Villages, fl |
|
Back to top |
|
|
GeoR38
Joined: 25 Jan 2006 Posts: 60 Location: The Villages, fl
|
Posted: Fri Apr 04, 2008 7:42 pm Post subject: 2 strokes |
|
|
In a message dated 4/3/2008 5:14:44 P.M. Eastern Daylight Time, donghe(at)one-eleven.net writes:
Quote: | Generally we would then spend a half a day trying to explain the reasons this happens, which I wont go into here, but rest assured...MORE oil in the mix is NOT better.
If you want to split hairs, Since all manufacturers calculate a safety margin for recommended mix...a little less is actually safer then a little more...but stick with recommendations from the manufacturer.
We engineers that work for engine companies dont calculate these ratios haphazardly believe me, because for us, its a matter of dollars spent on warranty claims...and the reputation of our products.
--------
Don G.
Central Illinois
Kitfox IV Speedster
Luscombe 8A |
Don, aren't you the Honda engineer that used to keep us on our toes about 2 cycles....what happened to you and I don't see any Kolbness in your signoff?.....eh, wha?? Oh, I think I remember you sold your Kolb as you built your Kitfox...
I always appreciated your well informed threads.
George Randolph
Firestar driver from the Villages, Fl
Planning your summer road trip? Check out AOL Travel Guides.
[quote][b]
| - The Matronics Kolb-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kolb-List |
|
_________________ George Randolph
Firestar driver, The Villages, fl |
|
Back to top |
|
|
Don G
Joined: 10 Jan 2006 Posts: 156 Location: Central Illinois
|
Posted: Fri Apr 04, 2008 8:33 pm Post subject: Re: 2 strokes |
|
|
HI George....Guilty as charged I guess,,,on both counts..No Kolb in the hanger anymore. Ive been spending the winter in my aircraft manufacturing facility (the pole-shed) trying to figure out how to give the KitFox the Visibility I miss so much from a Kolb!!!
| - The Matronics Kolb-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kolb-List |
|
_________________ Don G.
Central Illinois
Kitfox IV Speedster
Luscombe 8A
RV9A |
|
Back to top |
|
|
GeoR38
Joined: 25 Jan 2006 Posts: 60 Location: The Villages, fl
|
Posted: Fri Apr 04, 2008 8:59 pm Post subject: 2 strokes |
|
|
In a message dated 4/5/2008 12:36:14 A.M. Eastern Daylight Time, donghe(at)one-eleven.net writes:
Quote: | HI George....Guilty as charged I guess,,,on both counts..No Kolb in the hanger anymore. Ive been spending the winter in my aircraft manufacturing facility (the pole-shed) trying to figure out how to give the KitFox the Visibility I miss so much from a Kolb!!!
--------
Don G.
Central Illinois
Kitfox IV Speedster
Luscombe 8A
|
Planning your summer road trip? Check out AOL Travel Guides.
[quote][b]
| - The Matronics Kolb-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kolb-List |
|
_________________ George Randolph
Firestar driver, The Villages, fl |
|
Back to top |
|
|
knowvne(at)aol.com Guest
|
|
Back to top |
|
|
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|