Exhaust Delayed Scavenging

[7sleeper]

Dang I sure wish I understood more of what y'all are talking about! It's incredibly interesting anyway, but would be even more so if I could understand the terminology.

I Really Want to Learn, just don't know enough to get everything you are saying. Is there a book, or video that explains more in detail making a saw "Hot"?

Great thread anyway!

Cliff

There are dozens of threads about modding saws. Just look up "blsnelling" or "mastermind" for the beginning.

7

 

[GypsyCliff]

There are dozens of threads about modding saws. Just look up "blsnelling" or "mastermind" for the beginning.

7

OK 7sleeper, I have read other threads about "Snellerizing" but they still were too complicated and advanced for a rank amateur such as myself.

One thread showed, and told step by step about "porting a saw", but you have to speak the language to get it all. And I just don't! As in Speak the Language, OR Understand.

I have run my saw for over 30 years, and know enough to keep it running, sharp, and do minor repairs. But this is nothing like talking about "transfer ports", "welded pop ups", "reduced squish", and etc.

Just really need to a place to start at the start. Thanks for the input.

Cliff

 

[astnmacgto]

@GypsyCliff this book is a good read. It's a little complicated for one who does not understand how a 2 stroke engine works.

Start with the basics by Googling how a 2 stroke works, figure out just exactly what motions it goes through in order to run, then think of obvious ways you can optimize the design. Then you can start a book like the one pictured, it may seem a bit over your head but don't be afraid to read it a couple times. Google words that you don't understand, tear a saw down after reading it and see what everyone is talking about. Take some measurements, read the book again haha. It will all make sense after a while. It took me a little while to wrap my brain around the mechanics of it.

 

[GypsyCliff]

@GypsyCliff this book is a good read. It's a little complicated for one who does not understand how a 2 stroke engine works.

Start with the basics by Googling how a 2 stroke works, figure out just exactly what motions it goes through in order to run, then think of obvious ways you can optimize the design. Then you can start a book like the one pictured, it may seem a bit over your head but don't be afraid to read it a couple times. Google words that you don't understand, tear a saw down after reading it and see what everyone is talking about. Take some measurements, read the book again haha. It will all make sense after a while. It took me a little while to wrap my brain around the mechanics of it.View attachment 562253

Thanks. Steps to take:
1. Learn to read
2. Learn to use Internet
3. Learn to do a googely search
4. Read book several times
5. Build REALLY HOT SAW!

GypsyCliff's idea of lame humor!

Cliff

 

[astnmacgto]

Thanks. Steps to take:
1. Learn to read
2. Learn to use Internet
3. Learn to do a googely search
4. Read book several times
5. Build REALLY HOT SAW!

GypsyCliff's idea of lame humor!

Cliff

Yeah buddy!

 

[Chris-PA]

Dang I sure wish I understood more of what y'all are talking about! It's incredibly interesting anyway, but would be even more so if I could understand the terminology.

I Really Want to Learn, just don't know enough to get everything you are saying. Is there a book, or video that explains more in detail making a saw "Hot"?

Great thread anyway!

Cliff

This particular thread makes things seem more complicated than they are because it started out as an attempt to discuss a rather obscure detail of 2-stroke operation. That didn't go anywhere so I turned it into a build thread, and you don't need to understand that stuff. Like most of engine performance increase it's about making the engine into a better air pump - increasing port size, changing timing so it works at higher rpms, increasing compression ratio, reducing exhaust restriction and using larger carbs.

The first thing to do is to learn the basics of how a piston ported 2-stroke works, and there should be a fair amount of information about that on the Internet, including video animations.

 

[GypsyCliff]

This particular thread makes things seem more complicated than they are because it started out as an attempt to discuss a rather obscure detail of 2-stroke operation. That didn't go anywhere so I turned it into a build thread, and you don't need to understand that stuff. Like most of engine performance increase it's about making the engine into a better air pump - increasing port size, changing timing so it works at higher rpms, increasing compression ratio, reducing exhaust restriction and using larger carbs.

The first thing to do is to learn the basics of how a piston ported 2-stroke works, and there should be a fair amount of information about that on the Internet, including video animations.

Chris,

Thank you for your response. Right now I Know Nothing about "how a piston ported 2 stroke works".

I have been able to save a few hundred dollars by fixing my own saws, but that has Nothing to do with making a great running, lasting saw. And as you might have guessed, that's what I'm interested in.

Being a total neophyte makes it hard to wrap my mind around all you are talking about, but still very interesting. Thanks for sharing!

I will do more reading as you suggested.

Cliff

 

[GypsyCliff]

This particular thread makes things seem more complicated than they are because it started out as an attempt to discuss a rather obscure detail of 2-stroke operation. That didn't go anywhere so I turned it into a build thread, and you don't need to understand that stuff. Like most of engine performance increase it's about making the engine into a better air pump - increasing port size, changing timing so it works at higher rpms, increasing compression ratio, reducing exhaust restriction and using larger carbs.

The first thing to do is to learn the basics of how a piston ported 2-stroke works, and there should be a fair amount of information about that on the Internet, including video animations.

Chris,

OK, I looked at a bunch of info, and watched some videos. So here's my question; If you had a Stihl 028 Super that runs well, but NOT what I would call Super, what would be the Very First Thing you would do to it to make it run better?

This is a saw I bought new, and its absolutely my go to saw for most things. I just love this thing, and have always been impressed with how well it was thought out, and the fact that it has lasted and lasted.

I bought it originally because one of my oldest friends had a Still 031 that was inside his tiny wooden house when the house Burned to the Ground! After the remains cooled, my friend searched through the ashes, found the saw, replaced the melted plastic parts, and went right back to using it to cut his firewood! And he continued to use it for more than 20 years with only very minor repairs.

But I didn't wait 20 years of be convinced. As soon as he had that 031 running again, I went straight to the local Stihl dealer and bought me that 028. NEVER BEEN DISAPPOINTED! Not once, not ever.

BUT, it would be great if at times it had just a little bit more torque so that it could cut through hard, dry, big wood when cutting firewood. Cause that's basically all I use it for.

So number 1, I don't want to do Anything that's going to shorten the life of the saw. But number 2, if possible I'd like to soup it up a little bit.

Thanks in advance for any opinions you are willing to offer on this issue, and I look forward to hearing from you!

Cliff

 

[Chris-PA]

Chris,

OK, I looked at a bunch of info, and watched some videos. So here's my question; If you had a Stihl 028 Super that runs well, but NOT what I would call Super, what would be the Very First Thing you would do to it to make it run better?

This is a saw I bought new, and its absolutely my go to saw for most things. I just love this thing, and have always been impressed with how well it was thought out, and the fact that it has lasted and lasted.

I bought it originally because one of my oldest friends had a Still 031 that was inside his tiny wooden house when the house Burned to the Ground! After the remains cooled, my friend searched through the ashes, found the saw, replaced the melted plastic parts, and went right back to using it to cut his firewood! And he continued to use it for more than 20 years with only very minor repairs.

But I didn't wait 20 years of be convinced. As soon as he had that 031 running again, I went straight to the local Stihl dealer and bought me that 028. NEVER BEEN DISAPPOINTED! Not once, not ever.

BUT, it would be great if at times it had just a little bit more torque so that it could cut through hard, dry, big wood when cutting firewood. Cause that's basically all I use it for.

So number 1, I don't want to do Anything that's going to shorten the life of the saw. But number 2, if possible I'd like to soup it up a little bit.

Thanks in advance for any opinions you are willing to offer on this issue, and I look forward to hearing from you!

Cliff

The very first thing is usually a muffler mod, because it is relatively easy and the muffler is a separate part that be replaced. But I am not familiar with that particular saw, so I don't know what gains it will give. Each saw design is a little different, even if they all work on similar principles, so what will work best varies. After that, some benefit from a bit of spark advance, which again can be done without opening the engine. Also, some saws can use a larger carb - my old Mac SE3420 benefited quite a bit from just a larger carb and removal of the spark screen.

 

[GypsyCliff]

The very first thing is usually a muffler mod, because it is relatively easy and the muffler is a separate part that be replaced. But I am not familiar with that particular saw, so I don't know what gains it will give. Each saw design is a little different, even if they all work on similar principles, so what will work best varies. After that, some benefit from a bit of spark advance, which again can be done without opening the engine. Also, some saws can use a larger carb - my old Mac SE3420 benefited quite a bit from just a larger carb and removal of the spark screen.

Chris-PA,

Looking on eBay I have been continuously amazed at home much folks are asking/getting for 028s. Before looking recently, I had No Idea!

Then I tried to buy a couple and was very quickly outbid, and was Really Shocked. If they appear to be in good shape I've seen them go for right at $500! Seems totally crazy to me, but they are almost all-metal saws that are well made in lots of ways. I Almost won 1 auction by sniping, but at the very last second I missed out because my session expired! Anyway, will NOT make that mistake again.

So what kind of alterations do you have in mind for the muffler? ANYTHING you suggest, I will take under Serious Consideration.

I have hand tools of all kinds, but not much in the way of power tools. Drills, sanders, jig saw, and a Little bit of etc. But also not much in the way of space to work. BUT.... I make room and work on what needs doing. That's one thing my wife is Very Forgiving of, and almost never complains about my messes here in the living room floor. Just saying that I don't have a real shop right now. It's in the plans, but may be while.

Anyway, I've done lots of things during my 60 years, and know how to do lots. We built 2 houses here on our property, digging the foundation, pouring the concrete, laying the blocks for the first floor, building the stick built second floor, and doing the wiring and plumbing. Seems like I'm going on unnecessarily, just trying to explain that I am fairly competent.

So if you can give me suggestions, I'm open to following them to the best of my abilities. Like you said, starting with the exhaust system sounds like a good idea. And like you said, the muffler is cheap, and not permanently attached to the saw. Tell me your ideas, if you are inclined, and I will try my best to carry out your plans/ideas.

Thanks a ton for letting me pick your brain. Hoping to hear lots of your good ideas!

Cliff

 

[Chris-PA]

Chris-PA,

Looking on eBay I have been continuously amazed at home much folks are asking/getting for 028s. Before looking recently, I had No Idea!

Then I tried to buy a couple and was very quickly outbid, and was Really Shocked. If they appear to be in good shape I've seen them go for right at $500! Seems totally crazy to me, but they are almost all-metal saws that are well made in lots of ways. I Almost won 1 auction by sniping, but at the very last second I missed out because my session expired! Anyway, will NOT make that mistake again.

So what kind of alterations do you have in mind for the muffler? ANYTHING you suggest, I will take under Serious Consideration.

I have hand tools of all kinds, but not much in the way of power tools. Drills, sanders, jig saw, and a Little bit of etc. But also not much in the way of space to work. BUT.... I make room and work on what needs doing. That's one thing my wife is Very Forgiving of, and almost never complains about my messes here in the living room floor. Just saying that I don't have a real shop right now. It's in the plans, but may be while.

Anyway, I've done lots of things during my 60 years, and know how to do lots. We built 2 houses here on our property, digging the foundation, pouring the concrete, laying the blocks for the first floor, building the stick built second floor, and doing the wiring and plumbing. Seems like I'm going on unnecessarily, just trying to explain that I am fairly competent.

So if you can give me suggestions, I'm open to following them to the best of my abilities. Like you said, starting with the exhaust system sounds like a good idea. And like you said, the muffler is cheap, and not permanently attached to the saw. Tell me your ideas, if you are inclined, and I will try my best to carry out your plans/ideas.

Thanks a ton for letting me pick your brain. Hoping to hear lots of your good ideas!

Cliff

It sounds like you have the skills to modify a muffler, and that the 028 may be a very nice saw. The problem is I have never seen one and can't advise on the best way to mod one. My thing is modifying cheap saws no one else wants (like the subject of this thread) so I can have nice tools for my firewood cutting without getting into those $500 eBay wars.

I have no doubt that there are many who can give you good advice on modifying an 028 muffler, and other mods too, as Stihls are quite popular, but they're unlikely to see your comments here at the end of this rather obscure thread. You'd be best off making a new thread with a simple title asking for help with 028 mods - I'll eat my hat if there are not lots of responses!

 

[GypsyCliff]

It sounds like you have the skills to modify a muffler, and that the 028 may be a very nice saw. The problem is I have never seen one and can't advise on the best way to mod one. My thing is modifying cheap saws no one else wants (like the subject of this thread) so I can have nice tools for my firewood cutting without getting into those $500 eBay wars.

I have no doubt that there are many who can give you good advice on modifying an 028 muffler, and other mods too, as Stihls are quite popular, but they're unlikely to see your comments here at the end of this rather obscure thread. You'd be best off making a new thread with a simple title asking for help with 028 mods - I'll eat my hat if there are not lots of responses!

Thanks. Will take your advice and do exactly that.

 

[GypsyCliff]

It sounds like you have the skills to modify a muffler, and that the 028 may be a very nice saw. The problem is I have never seen one and can't advise on the best way to mod one. My thing is modifying cheap saws no one else wants (like the subject of this thread) so I can have nice tools for my firewood cutting without getting into those $500 eBay wars.

I have no doubt that there are many who can give you good advice on modifying an 028 muffler, and other mods too, as Stihls are quite popular, but they're unlikely to see your comments here at the end of this rather obscure thread. You'd be best off making a new thread with a simple title asking for help with 028 mods - I'll eat my hat if there are not lots of responses!

Chris,

Did as you suggested, already getting lots of recommendations. Thanks for your help!

Cliff