I'd like to know a psi number to shoot for as far as crankcase conpression goes. I have been thinking about crankcase compression for a while but i havent come across any good info yet to explain it. I've been shooting for 40° like you said as per instruction i have recieved from probably the same teacher. I was under the impression that more crankcase pressure helped with lower rpm power because the volume and velocity of air moving the engine is rpm dependent. Less rpm=less air speed. But i have no knowledge that supports that theory.
Yep. They build high crankcase pressure and force the charge up the transfers and into the upper cylinder at a high velocity. The large blowdown time is so the spent gasses have time to leave the cylinder through the choked up exhaust before the fresh gas enters, but the muffler is so restricted that the spent gasses still need to be pushed out by the high pressure fresh charge. So...They build everything as tight as can be to achieve high crankcase pressure and high velocity charge to overcome a rediculously clogged up exhaust. And what they did was very successful...because the difference between an open and nicely modded muffler when compared to a stock muffler was negligible. Hardly any difference.
@@novicelumberjackso this being the case; porting is much more effective than modding the exhaust. At least on modern day saws correct? Trying to learn as well.
@@jeremydawkins8399 No. On this saw specifically. On the Husqvarna 5 speries saws, they tend to get a bigger gain from a muffler mod than they do most port jobs.
Forrest...thanks for your concern, but...there are only three reasons to make pretty ports. I'll list them in order of importance in relation to a percentage of times in which a builder may choose to make pretty ports. 85% of the time- The builder is just trying to appease an ignorant customer, because nearly all builders know that pretty ports do not equate to power. 10% of the time- The builder himself is ignorant and thinks he will get more power by having pretty ports. 5% of the time- The builder is building a ridiculously high end build where yes...pretty ports may make the difference between winning and losing a race. Since none of these reasons apply to me, I think I'll leave them as they are. As a builder, you have to know when the juice is worth the squeeze. These ports could be beautiful...it would make zero difference in how the saw runs and operates.
I've heard some of the more experienced porters argue that a rougher port surface is beneficial to airflow. And something about fuel scattering at a molecular level. Don't know if it's theoretical or not but it sounds good! ✌️
Great explanation of what you did and why. Looking forward to seeing how it performs.
Roll pins. Those are really nice saws, cant wait to see how it turns out! ✌️
Yes! Thank you!
Boedy, Good explanation and theory!!!! I like the thinking out of the box!!!
Well explained man
Nice work look 👌 👏 👍 😍 💪 🙌
Can't wait . I'll bet it will be a great little saw
I think just about all of this makes percect sense.
Good discussion
I'd like to know a psi number to shoot for as far as crankcase conpression goes.
I have been thinking about crankcase compression for a while but i havent come across any good info yet to explain it. I've been shooting for 40° like you said as per instruction i have recieved from probably the same teacher.
I was under the impression that more crankcase pressure helped with lower rpm power because the volume and velocity of air moving the engine is rpm dependent. Less rpm=less air speed. But i have no knowledge that supports that theory.
Hi Novice 😊 . Perfect job 👍👍👍
You forgot to say if this saws gna be for hard or soft wood 😝 👌🤘🤘
Sweet
🎉
👍👍
So thats how they get away with such choked off lowers. Makes sense👍🏻
Yep. They build high crankcase pressure and force the charge up the transfers and into the upper cylinder at a high velocity. The large blowdown time is so the spent gasses have time to leave the cylinder through the choked up exhaust before the fresh gas enters, but the muffler is so restricted that the spent gasses still need to be pushed out by the high pressure fresh charge. So...They build everything as tight as can be to achieve high crankcase pressure and high velocity charge to overcome a rediculously clogged up exhaust. And what they did was very successful...because the difference between an open and nicely modded muffler when compared to a stock muffler was negligible. Hardly any difference.
@@novicelumberjackso this being the case; porting is much more effective than modding the exhaust. At least on modern day saws correct? Trying to learn as well.
@@jeremydawkins8399 No. On this saw specifically. On the Husqvarna 5 speries saws, they tend to get a bigger gain from a muffler mod than they do most port jobs.
👍🆙BigGuy
Now is that built for softwood or hardwood? Lol. Great vid👍👍
Boedy I know it’s a give away saw but you could clean the transfers up a bit after all it represents you out in the saw world just saying as a friend.
Forrest...thanks for your concern, but...there are only three reasons to make pretty ports. I'll list them in order of importance in relation to a percentage of times in which a builder may choose to make pretty ports.
85% of the time- The builder is just trying to appease an ignorant customer, because nearly all builders know that pretty ports do not equate to power.
10% of the time- The builder himself is ignorant and thinks he will get more power by having pretty ports.
5% of the time- The builder is building a ridiculously high end build where yes...pretty ports may make the difference between winning and losing a race.
Since none of these reasons apply to me, I think I'll leave them as they are. As a builder, you have to know when the juice is worth the squeeze. These ports could be beautiful...it would make zero difference in how the saw runs and operates.
@@novicelumberjack
Ok I understand now Boedy I learn something new everyday. 😎
I've heard some of the more experienced porters argue that a rougher port surface is beneficial to airflow. And something about fuel scattering at a molecular level. Don't know if it's theoretical or not but it sounds good! ✌️
Comment from me