A Trio of 660’s

[Lightning Performance]

View attachment 113236

These are timed roughly the same in a Stihl 460 cylinder.

Which one traps more volume under it at intake floor closing?

Will that make any difference when the difference in volume will be the same at int close - volume at BDC?

The upper is open for longer under the piston lands on the single ring piston. So there’s more time for the tunnel to fill/mix through the upper and lower during induction cycle.

Does any of it matter?

@drf256
Were the two 036/360s you built, I ran, at the TNgtg set up with single or double ring pistons?

 

[Lightning Performance]

Exhaust before....
View attachment 113405

Exhaust ready for chamfer
View attachment 113406

From the outside. Still some arc to the roof. I didn’t go as square as originally intended. The ring land has been weakened by the pop up. Some curvature should help tuck those suckers back in.
View attachment 113407

Intake
View attachment 113408

I like those ports. Easy on the rings and intake skirt.

 

[GoBigBlue1984]

Just wanted to share some pics of how I epoxy the intake. Start with some clear packing tape and a piston.


Once it’s setup. This isn’t the finished photo but it gives you an idea. Notice the valley between the aluminum and the epoxy. I don’t want that. I’ll add some more epoxy to transition from the intake boot.

 

[GoBigBlue1984]

As it stands right now I have 134 degrees of intake duration. I want just a little bit more to start with.

 

[Lightning Performance]

As it stands right now I have 134 degrees of intake duration. I want just a little bit more to start with.

Your pretty short on intake time.

 

[GoBigBlue1984]

Your pretty short on intake time.

You are correct. I wouldn’t ever use that. I was only showing how much epoxy I put in it. I’m going to start with 150. I suspect it’ll make a good runner there. Though I normally like a tad more. The strongest 660 I’ve built to this point 156.

 

[Lightning Performance]

When you fill the "ditch", do you carve some of it back out or flat across the floor?

 

[drf256]

@drf256
Were the two 036/360s you built, I ran, at the TNgtg set up with single or double ring pistons?

Sorry, just saw this Ken. Double ring stock piston saws.

Brett, Impressive Work my friend.

 

[David Young]

You are correct. I wouldn’t ever use that. I was only showing how much epoxy I put in it. I’m going to start with 150. I suspect it’ll make a good runner there. Though I normally like a tad more. The strongest 660 I’ve built to this point 156.

Do you suspect this will be one of the top three strongest saws?

 

[GoBigBlue1984]

Who knows? Maybe I got lucky and the 156 intake saw would’ve been a good runner at 170. Too many variables. I try to make note of each saw and if it seems to run better than another I’ll highlight what I did to that saw. But even that doesn’t always work out. This third one I’m going to do what I can without lowering the jug any and only widening exhaust/raising uppers and muffler work. Come to think of it I dont believe I’ve ever built a 660 without cutting the band and taking less than .040 from the base.

 

[GoBigBlue1984]

Sorry, just saw this Ken. Double ring stock piston saws.

Brett, Impressive Work my friend.

Thank you Doc.

 

[GoBigBlue1984]

Do you suspect this will be one of the top three strongest saws?

Dare I say.......this......was a unicorn jug

 

[David Young]

Maybe this will help

 

[cus_deluxe]

Are these all “maxed out” yet?

 

[GoBigBlue1984]

Hah! No but I’m gonna need you to send me your saws. Free port job for research purposes

 

[huskyboy]

Are these all “maxed out” yet?

If it ain’t popping, it ain’t maxxed out.

 

[GoBigBlue1984]

I have it on good authority.......cough cough David Young cough cough ......that this is just right....

 

[GoBigBlue1984]

We don’t need no stinkin hearing protection

 

[Mastermind]

Reading thru this thread leaves me feeling a bit in awe of the skills, and knowledge of our membership.

You guys are a hell of a group of saw heads.

 

[GoBigBlue1984]

Reading thru this thread leaves me feeling a bit in awe of the skills, and knowledge of our membership.

You guys are a hell of a group of saw heads.

I personally learned much from you, more than you’ll ever know. Others too.

I’m just a hack with some cool toys.