Mastermind Revisits the MS661

[jake wells]

new recipe,,,, so you sharpened your chain hahaha.

 

[Mastermind]

This saw has not had the intake touched in any way. I've not touched the piston either. At all. This is white oak, and a 28" bar.

 

[jmssaws]

Last one I did is 98 120 83 180lbs
Very little grinding and it's a great runner. I like the higher exhaust

 

[Moparmyway]

What did you end up with for intake ?

 

[jmssaws]

The last 3 saws I've built have proven to me 3 times that widening the intake does absolutely nothing in a 066 cylinder anyway

 

[Mastermind]

What did you end up with for intake ?

Let's talk about crankcase volume and it's effect on blowdown first.

 

[Moparmyway]

Let's talk about crankcase volume and it's effect on blowdown first.

The one with more blowdown was stronger out of my two

 

[jmssaws]

The one with more blowdown was stronger out of my two

Decrease case capacity and you need more bd.

 

[Mastermind]

The one with more blowdown was stronger out of my two

Do you think that case volume plays a role in exhaust height or the amount of blowdown an engine needs?

 

[jmssaws]

I've built 66's from 14 to 25 degrees of blow down. All run good buy there's lots of variables to it.

 

[MustangMike]

I would think the smaller case capacity needs more intake duration, but what the heck do I know! Maybe the higher case pressure off sets it???

 

[Redfin]

Do you think that case volume plays a role in exhaust height or the amount of blowdown an engine needs?

I see a tighter case wanting a shorter primary which in turn is going to need a higher ex.

 

[Moparmyway]

Do you think that case volume plays a role in exhaust height or the amount of blowdown an engine needs?

From what I've seen, the bigger saws have more case capacity, so the more blowdown you can run......... However I doubt that's the way it is for every saw. The 90cc's seem to have some more in them as I gave more blowdown for long and short bars, but shorter bars like more intake.

Case volume has only been reduced in my builds, and longer blowdown has been stronger ......... So that contradicts what I'd believe from my first sentence.

98/120 seem wicked so long as intake is matched to load (bar length)

 

[Redfin]

This is 105/129/87. Stupid torque but it just didnt want to make the rpms.

This one is 99/118/121/79. I should have raised the trans in increments to test but I didnt want to be sad if the longer bd was better.

 

[Mastermind]

I agree with your sig.

"Its what you learn, after you already know it all, that counts"

And here's another.

Now that I know more.......I have so much more to learn.

 

[jmssaws]

Are we having a riddle contest?

 

[Redfin]

I agree with your sig.

"Its what you learn, after you already know it all, that counts"

And here's another.

Now that I know more.......I have so much more to learn.

I heard a good one last night about marraige. "Do you always want to be right, or do you want to be happy?"

 

[Moparmyway]

I agree with your sig.

"Its what you learn, after you already know it all, that counts"

And here's another.

Now that I know more.......I have so much more to learn.

Yup, you nailed it. Now that I know more, I have so much more to learn.

But lets get back to your question Sir ....... Do YOU think case volume plays a role in higher exhaust or blowdown duration ?
Please elaborate what you know and what more you have learned

 

[junkman]

More case volume =turtle
Less case volume = potatoe

 

[Moparmyway]

More case volume =turtle
Less case volume = potatoe

See ?????
I have sooooo much more to learn