"tear drop" mods on sleeves

[anthony_marquart]

Bump!!! Is this a dumb question or did I not explain it well?

I have been looking at different versions of teardrop mods to piston sleeves. These cuts are usually on one end of the port, the end nest to the exhaust port.

Why is the slot only at one side of the port? Wht would be the result if the cut was take from one side of the port all the way to the other?

 

[Jerry Wyss]

There's a guy,"Tonymods" over in OB forum, 1st page, down a way's, in "Thunder

Tiger Mods" that did this very thing your talking about. As to be to one side I think

to one side on the "directional" ports,, to get a desired swirl action to the Wiz Bang.

I doubt very much if it's going to make that much Dif on anything,,but I'm sure

someone on here will "Defend it to Their Death" or to the "Exclusion Of All Else"

But after reading the "Tuners Handbook" that I loaded off this site,, We are just

"kidding" ourselves into thinking that "just one thing" we do to an engine is gonna

make a whole lotta dif. It's a Huge subject and one thing relates to "dozens" of

others and it's "impossible" to be a 100% accurate on anything. Boy,,I hope that

helps :lol:

 

[John Finch]

Sounds like you been there done that. I will say, when I was moding my Picco 67 engines....... all the mods I did could be equalled to as much power as two little cuts on the sleeve in the spot you are refering to. It has to do with getting the perfect burn on the top of the piston. If you look at your piston top after running for a while you will see a burn pattern. When that burn pattern is full and round on the piston.......Wham....... You got it man!

John Finch

 

[Jerry Wyss]

Excuse Me John While I Go and Hide Under the Couch h34r:

I've tried it on the Thunder Tiger OB's,,This side,that side,,Both

Sides. What I've found out mostly with these motors,,and true

with all engines,,is that modifications are made in several areas

and they have to be in concert with each other in a effort to reach

a desired area of performance. A Picco 67 is usually a perfomance

engine to start with,,a .21 TT OB is not. I've been dickin' with these

motors for some time now,,and been changing one thing at a time

,,and doin',,perdy good,,but until I read The "Two Stroke Tuners

Handbook", only then did I realize that it has to be a well layed out

plan and it goes "Stem to Stearn" of these little "jewels",,From the

inlet of the carburator to the exit of the exhaust. It's like "baking"

a cake,,Hey I'm Gonna Bake a Cake,,I've Got the Sugar! Well it's

gonna take alot more than sugar,,, or,,CAAAK!

Hey! I'm Gonna Go Buy A Tuned Pipe! Tuned For What?,,,????

The,????, is whats Got to be known or we're just shooting in the dark.

And thats what I'm on a mission to do,,find out what all these ???? are.

Oh, bye the way,,Your columns in the Boat Modeler magazines were

always my favorite.

 

[Slideblues]

And if all else fails.....You can make a mean Cajun Shrimp Cerole :lol: :lol: :lol:

On a serious note:

Actually guys there is one mod "The only thing I have heard it called was the Picco mod" Where ya chamfer the side of the sleeve up to the port, Wish I still had a pic, but I dumped it a few years back.

Gene

 

[Jerry Wyss]

Hey Slidey, Did you see the pics that "Tonymods" posted in "Thunder Tiger Mods"

I think it's in OB Forum,,,,go ahead,,you won't get too soiled

 

[Slideblues]

:lol: Jerry yea, I just went back and looked at the pics, It was not that Rad, just a groove the same width as the port running straight down the side of tha sleeve,

Gene

 

[Jerry Wyss]

I didn't see the mods this time :blink: I need a break h34r:

 

[Don Ferrette]

" A Picco 67 is usually a perfomance engine to start with,,a .21 TT OB is not."

Well Jerry I had a 21TT o/b that Rod Geraghty did up for me & it was a MONSTER!!

 

[John Knight]

:lol:   Jerry yea, I just went back and looked at the pics, It was not that Rad, just a groove the same width as the port running straight down the side of tha sleeve, Gene 

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Take a small grinding stone in a dremel and cut a small notch on the outside of the sleeve from the bottom edge of the port to the very bottom of the sleeve. It is a vertical groove. Only notch about 1-/32" deep and only the true width of the port. Polish it very well with a polishing stone. On the bottom of the sleeve, thin out the very bottom edge and taper it towards the cylinder. Do only the outside of the sleeve and NEVER touch the exhaust port or the area below the exhaust port. You will end up refacing about 2/3rds of the bottom of the sleeve. It opens more air and fuel flow into the cylinder. You will be surprised how much this helps without changing the engine porting or timing. I do not normally change the port sizes or openings.

Be patient with it and go slow. If you look carefully inside the engine case you will see matching cutouts to allow fuel/air mix to enter the ports. All you are doing is enlarging the depth of those cutouts. If you have doubts about it then do it a small amount and test it. I have seen the face ground about 1/16" before but never deeper. You do want to make the sleeve too thin. REMEMBER, work only from the bottom of the sleeve to the bottom of the intake, booster and side ports. Do not go above those ports.

I have no digital camera yet but Santa is supposed to bring me one. Then I have to figure out how to work it.

 

[Jerry Wyss]

" A Picco 67 is usually a perfomance engine to start with,,a .21 TT OB is not."
Well Jerry I had a 21TT o/b that Rod Geraghty did up for me & it was a MONSTER!! 

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Your kinda makin' my Point,,I guess,,Rod Knows what he is doin',,Tim Duggan

Knows what he's doin',,,I want to be one of those guy's that know what I'm

doin'. Instead of, Hey Jerry! "Make your headspace so and so", or "Cut your

sleeve to,,whatever. The information is All Great,,don't get me wrong,,,I just

want to know how to come to these modifications aside from trial and error or

cut and fit,,I'm intrested in the "mechanics" of how a certain mod will effect

the outcome. Thats why I like the "Hand book" , it has the formulas and the

math,,right there,,and also some "rule of thumb" stuff that works to keep

me from Totally Going Back To The School of Engineers! Finally I can know

myself,, and it's starting to make sense for a change. neener,neener,,neener

 

[EatMyShortsRacing]

Happiness is a warm Dremel!!!!

 

[Jerry Wyss]

Happiness is a warm Dremel!!!!

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My Wife Loves Your Avatar

 

[EatMyShortsRacing]

Happiness is a warm Dremel!!!!

78043[/snapback]

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My Wife Loves Your Avatar

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Kitten Kong!!!!

 

[Jerry Wyss]

Man, I'm missin' all that Sun you guy's are now gettin'

It's like livin' on the dark side of the moon,,,'cept it's alot

wetter.

 

[EatMyShortsRacing]

Yep... Sun and heaps of it...... even in Melbourne!!!!

was almost 40 degrees C here over the weekend....