Mastermind Meets The MS661 Again

[Mastermind]

I really don't do anything special.

Just attention to detail......and I keep good notes.

 

[Mastermind]

A few more pics.

We'll be running a little fuel thru these saws today.

 

[Mastermind]

 

[Mastermind]

 

[spencerpaving]

all of this overthinking is leaving me totally confused...... but aleast it hasn't derailed yet

 

[HuskStihl]

Randy, how close to u'r 390 recipe will the 661's numbers wind up?

 

[KG441c]

Nothing wrong with learning alil bit while Waitin on Randy?

 

[Moparmyway]

I really like that exhaust !!

 

[old-cat]

Lynn, I'm thinking you may have a lot of good things to input here.

No, not a lot, maybe a little. What I'm seeing is a whole lot of hot exhaust up there high when the piston is opening the ex port. That's where the fresh charge needs to go. So, those finger ports aiming straight up seems right. I don't like the transfer ports blowing straight across the piston top.

 

[singinwoodwackr]

wow, you really opened up the muff. are you going to try some tests with just that mod before porting?

 

[Mastermind]

Yeah, I still have a bone stock saw on the shelf.

I'll try just that muffler, then that epoxy jug on it.

It's nasty out today. Ice on everything. I'm porting 461s and waiting on test cuts.

 

[fordf150]

chrysler in the early 90's on their 4cyl engines went from a large oval shaped chamber to an almost heart shaped chamber to improve mixing but none of that applies here. the mixing of air and fuel comes from pushing the mix up through the transfers and the natural turbulence of the intake and crankcase? then its a matter of the fresh fuel/air pushing out the burned fuel with as little dilution as possible. does that mean that transfers need to flow across, up, or toward the intake to push the exhaust gasses out? looking at all the junk jugs i have laying around they all appear to have flat ceilings to the transfers and be aimed toward the intake. so flow is across the piston and toward the intake.

tryin to learn a bit while im on here instead of doing the mountain of work sitting in front of my bench

 

[Mastermind]

The dual transfer jugs.....well, they are antiques.

Look at a quad ported jug. The two nearest the intake are normally angled upward......and the two on the exhaust side are flat.

Mull that over in the ol' mush melon awhile.

 

[KG441c]

The dual transfer jugs.....well, they are antiques.

Look at a quad ported jug. The two nearest the intake are normally angled upward......and the two on the exhaust side are flat.

Mull that over in the ol' mush melon awhile.

So r 2 of them for scavenging exhaust and 2 for charging the chamber with fresh fuel?

 

[KG441c]

2 of the ports in a quad setup serving the same purpose as fingers?

 

[Ray Bell]

2 of the ports in a quad setup serving the same purpose as fingers?

Great thread...WAY over my pea grain noggin...but great thread.

 

[Deets066]

Hey Randy, you figured out how you want to finger port that 088 yet?
Same recipe as smaller saws or a little different?

 

[KG441c]

The dual transfer jugs.....well, they are antiques.

Look at a quad ported jug. The two nearest the intake are normally angled upward......and the two on the exhaust side are flat.

Mull that over in the ol' mush melon awhile.

Do the 2 ports nearest the intake side open a tad sooner than the exhaust side transfers?

 

[Mastermind]

Hey Randy, you figured out how you want to finger port that 088 yet?
Same recipe as smaller saws or a little different?

Oh yeah.......I've got that one done. (in my head anyway) lol

Do the 2 ports nearest the intake side open a tad sooner than the exhaust side transfers?

Sometimes.

 

[Deets066]

In dual transfer jugs what is ideal angle or shape? Has anybody done tapered upper transfers to possibly increase velocity?