ms 461 woods port race thing

[tree monkey]

it does like it's fuel

 

[CJ Brown]

This a great thread - as others have stated before. I have a question for you guys. I always thought the idea behind scavenging the cylinder was to direct the fresh charge towards the back of the cylinder first - essentially filling the cylinder with fresh charge from back to front, while displacing the spent charge and by default directing it out the front of the cylinder. If this is the theory, wouldn't it be better to open the secondaries first? I would think that by opening the primaries first you may be actually trapping a portion of the spent gasses in the back of the cylinder, then when the secondaries open, a pressure wave is formed that could force the primary charge out the front of the cylinder, with the trapped spent gasses coming behind it. In actuality, it would more likely be a mixer of fresh primary charge and spent gasses combined, which is not ideal either.

I would think that by opening the secondaries first, the back of the cylinder would be filled with fresh charge initially, directing the spent charge up and forward. Then, when the primaries opened, they would combine with fresh charge at the rear of the cylinder, while simultaneously contributing to pushing the spent gasses up and forward. This would also contribute to a denser/cleaner incoming charge, and less combining with the spent charge.

Thoughts?

 

[huskihl]

View attachment 107022


good call joey

No shìt....it does make a difference

 

[paragonbuilder]

epoxy in the transfers now, will be testing again in the morning

I know you are strapped for time, will you test with the plug in the same orientation first to see any changes, than index the plug and try again? Or all at once for the sake of time?

 

[paragonbuilder]

This a great thread - as others have stated before. I have a question for you guys. I always thought the idea behind scavenging the cylinder was to direct the fresh charge towards the back of the cylinder first - essentially filling the cylinder with fresh charge from back to front, while displacing the spent charge and by default directing it out the front of the cylinder. If this is the theory, wouldn't it be better to open the secondaries first? I would think that by opening the primaries first you may be actually trapping a portion of the spent gasses in the back of the cylinder, then when the secondaries open, a pressure wave is formed that could force the primary charge out the front of the cylinder, with the trapped spent gasses coming behind it. In actuality, it would more likely be a mixer of fresh primary charge and spent gasses combined, which is not ideal either.

I would think that by opening the secondaries first, the back of the cylinder would be filled with fresh charge initially, directing the spent charge up and forward. Then, when the primaries opened, they would combine with fresh charge at the rear of the cylinder, while simultaneously contributing to pushing the spent gasses up and forward. This would also contribute to a denser/cleaner incoming charge, and less combining with the spent charge.

Thoughts?

I see your thinking. I know this has been tested before....
I’m not sure there is a common consensus.
I know when Scott reduced the stagger of 7 degrees he lost power. Perhaps going further it would come back?

I think the idea of the primaries opening first, if they are aimed back enough, is to sweep the top of the piston toward the intake, under the spent charge, then up the back wall and through the chamber towards the exhaust in a loop.

 

[tree monkey]

I know you are strapped for time, will you test with the plug in the same orientation first to see any changes, than index the plug and try again? Or all at once for the sake of time?

all at once, about out of wood also. just hope to hell it don't go back words.

 

[Code_Red]

Awesome thread Scott. For someone with a visual learning mind and who knows little more than "ported saw = fun" this is truly cool to see what all goes into this process from the builders. Keep it up!

 

[paragonbuilder]

all at once, about out of wood also. just hope to hell it don't go back words.

Did you epoxy both sides? Can’t imagine a better angle towards the intake can hurt, but if it does it shouldn’t be too hard to dig it back out.

I believe you are very close to calling this maxxed out!!!!! [emoji23]
Plus it’s good enough for who it’s for...

 

[Terry Syd]

A couple of issues that have been brought up on this thread. First, the plug orientation. Plug manufacturers don't always use the same thread starting point. Many of the manufacturers will have SIX different starting points. That means if you sort through the plugs you can find one that will line up where you want it. No need to use shims and increase the volume in the combustion chamber. (I think they probably do that so that tuners will purchase EXTRA plugs!)

The second issue is raising the transfer height. Whether it is raising one or both of the transfer ports, it REDUCES the induction stroke of the engine. The engine can only SUCK IN mixture from the time the transfers close to TDC. If you raise the transfers, you reduce the induction stroke that can pull in mixture.

The best approach is to get the transfers flowing well and when an increase in time/area is required to raise the powerband, to then increase the width of the port (area) without increasing the height (reducing the induction stroke).

 

[MustangMike]

So tomorrow, Scott is going to test 3 different modded saddles .... I'm just kidding!

Great Job Scott, almost at 17,000 and the darn plug looks rich!

Looks like tons of oil, do you think 40:1 would work better? It would also increase the octane, which cant hurt!

That saw is screaming!

 

[huskyboy]

Did you epoxy both sides? Can’t imagine a better angle towards the intake can hurt, but if it does it shouldn’t be too hard to dig it back out.

I believe you are very close to calling this maxxed out!!!!! [emoji23]
Plus it’s good enough for who it’s for...

It’s not popping yet, so it’s not quite maxxed out yet

 

[huskihl]

It’s not popping yet, so it’s not quite maxxed out yet

^
He's right, you know

 

[drf256]

Wow, a lot has gone on here. Lots of good thoughts.

Scott, how are you confirming that the coking of the piston crown ain’t being burned off by the flame front by the plug indexing? Could be affecting pattern and misleading everyone.

Roy brings up a great point. The PTO side with a Right handed burr always makes me have to cut at the wrong angle to avoid chatter. The finish lines in the roof point towards the exhaust for me. I try to make the finish at the correct angle, but anyone who’s ground uppers with a R angle tool knows what I mean. It’s always harder to not inadvertently make the Ex side of the PTO upper wider. After what I’ve seen above, the left hand cutter will be my finish step from now on.

You probably are tired of opinions, but here’s mine.

Obviously index plug. Look at pattern.

Refinish your PTO side roof with a Left hand cutter, making/confirming the cut marks go in the direction of the intake.

Sacrifice one of your test pistons to open the PTO side primary (and possibly secondary) before the flywheel side. I’ve had husky jugs with uneven factory transfers. Some say it was a defect, others that it was done intentionally to cause Chamber swirl by making the charge fronts collide and create an eddy.

This thread has taught me a lot. Thank you again.

BTW, does the jug already have transfer over the Ex roof? Kinda looks it.

 

[paragonbuilder]

Wow, a lot has gone on here. Lots of good thoughts.

Scott, how are you confirming that the coking of the piston crown ain’t being burned off by the flame front by the plug indexing? Could be affecting pattern and misleading everyone.



Obviously index plug. Look at pattern.

Good thinking Doc,
That’s how this subject of indexing came up.
Joey said he thought the plug electrode was aiming towards the flywheel by the patterns and misleading the reading.

Scott added some epoxy to redirect the intake side of the primaries and is testing again this morning. He’s gonna try and find a plug that is indexed better.

 

[paragonbuilder]

Looks like tons of oil, do you think 40:1 would work better? It would also increase the octane, which cant hurt!
!

Mike, reducing the oil would make the mix more volatile, which is a lower octane. Which unless it started detonating could be a good thing.
Probably what you meant.

 

[Deets066]

Mike, reducing the oil would make the mix more volatile, which is a lower octane. Which unless it started detonating could be a good thing.
Probably what you meant.

Personally I'd stick with 32:1 at high rpm

 

[paragonbuilder]

Personally I'd stick with 32:1 at high rpm

Same here, for everyday work/play, but when racing, where milliseconds count...

 

[Deets066]

Same here, for everyday work/play, but when racing, where milliseconds count...

Milliseconds do count, but the saw still has to live

 

[paragonbuilder]

Milliseconds do count, but the saw still has to live

[emoji106]

 

[XP_Slinger]

Is this saw getting into pipe territory? With how Scott has gotten it flowing one can’t help but wonder. Of course it’s not an option by the build rules.