K&B Sleeve Mods

[Ed.R]

I have a .21 and a .45 and I was wondering if there are any sleeve mods that can be done to increase peformance at all and if so are they legal in the IMPBA ?

Thanks in advance

Ed.R

 

[MarkScott]

Ed,

Take a look here.. As IMPBA "sport" rules state only the in / out is check, anything goes inside....

 

[Ed.R]

OB nUt ,

Thanks for the info and by the way great sites you have the WOF build will help in the future for sure .

Ed.R

 

[MarkScott]

Ed,

Glad the sites help out.. What they are there for...

 

[chunk t]

Ed,

I'd recommend taking a look at the tech papers @ rcboat.com.

Before you make the first cut, measure twice and see if there is an alternative to cutting (i.e. sleeve shim) that will get you to the numbers you are shooting for.

chunk t

 

[ryan_t888]

What I do is tear drop the side ports and chamfer the boost ports. I remove material right from the bottom of the sleeve up to the bottom of the port.

I also do rod, piston and crank work but the most performance gained will be from material removal on the sleeve.

It is simple to do, you really can't go wrong as long as you leave the chrome alone!

Ryan

 

[topfuel443]

It is simple to do, you really can't go wrong as long as you leave the chrome alone!

Ryan

Wow! Thats a pretty bold statement. :huh: Ive seen some sleeves that have gone REALLY wrong... Dremels should be banned from some peoples hands. Chrome touched or not...

~James

 

[RodneyPierce]

It is simple to do, you really can't go wrong as long as you leave the chrome alone!

Ryan

Wow! Thats a pretty bold statement. :huh: Ive seen some sleeves that have gone REALLY wrong... Dremels should be banned from some peoples hands. Chrome touched or not...

~James

AMEN to that!!!!!!!!!! :lol:

 

[ryan_t888]

Wow! Thats a pretty bold statement. :huh: Ive seen some sleeves that have gone REALLY wrong... Dremels should be banned from some peoples hands. Chrome touched or not...

~James

I don't quite understand what you mean by "really wrong." What can one do to make a sleeve go "really wrong."

I do this to all of my nitro engines whether it would be plane, car or boat.

Most people believe if they were to touch the sleeve, it will become obsolete. And for this reason they do not touch them.

Ryan

 

[topfuel443]

well...

If when you say "dont touch the chrome". you mean do not alter the timing by raising/modifing the port openings, then I understand what YOU mean. Me saying that it was a bold statement, was just that. It IS a bold statement to say "you really cant go wrong" without explaining to the hundreds of people who read this forum and misinterpret that as to say go ahead and hack on the sleeve all you want will, more likely than not, end up with a pile of useless parts.

I have found more to be gained from simply matching the port openings on the sleeves to the case transfer tracts, (especially on K&B's, which are the motors we are discussing, they dont even come close to lining up.), and also finding the correct head bowl volume and squish band shape/clearance. Making sure the parts fit is correct, i.e., the rod bushing clearance, front housing/crank clearance and making sure the liner "seats" squarely are far more beneficial than grinding on the outside of the sleeve. Crankcase volume comes into play when too much material is removed. Two Stroke Engines need to have an extremely delicate balance of case volume to be efficient. An efficient engine is a fast engine.

Sure, you can turbo the crank and head button, cut all sorts of trenches, notches, and everything else known to man in the sleeve, but it doesnt add up to a hill of beans without the total package.

To simply state that "you really cant go wrong as long as you dont touch the chrome" is a bit misleading, thats the only point im trying to make.

~James

 

[Jerry Wyss]

Well I don't understand the "don't touch the chrome" thing,, I have cut the EX port roof

on over 30 TT sleeves and about 6 boost ports too, over a span of 11years.

I have had a chrome chip come off two sleeves, but thats when I learned that the cheap diamond bits are better than carbide cutters. Finished up with the abrasive impregnated hard rubber style of Dremel bits,, all Dremel work with dulling the sharp chrome edges with 600 wet&dry in a small rolled shape.

Yeah, I've screwed up 3 with the carbide (cut too high EX port) but have been able to use them in cool dense air without sleeve shims,, engine hit's like a 30-06 but it sure is fun.

TT piston & sleeves at one time were $40, sometimes less,,,experimentation with a more costly sleeve could get painful,, I've had perdy good luck.

It is also important to remember that the TT is a "geared engine" and I can afford a more radical timed engine than the direct drive brothers.

I would also ditto "James" post, other things have to come into play with these mods to

make it all work together. I have never seen much from cutting on the outside of the sleeve,

but that's just me.

 

[GRoth265]

OH-Man Where to start! Exh. port timing,crank port timing,turbo cut cranks and so on. But what you really need to ask yourself is How long do I want it to live? Incredible performance is possible but it doesn't do you much good if it blows every 6 heats unless your willing to spend the coin and have a backup ready to go in your tool box B) Just my .02 worth Greg

 

[dave roach]

There's a right way and a wrong way to mod a engine.If you what to dance you got to pay the fiddler.I have seen stock engines brain new out of the box blow a rod or a piston or brake a crank.The chain is only strong as it weakest link.

Dave Roach

 

[VansRacing]

The $164,00.00 question is:

Why can't anyone make a "stock/sport" (with no pipe) K&B 3.5cc O/B engine run over 52mph on a tunnel boat?

Fact: The stock K&B O/B's will run 65mph on a good O/B hydro...but a stock O/S 3.5cc O/B will not run any faster than that on the same hydro but on a tunnel boat, it will lap the K&B.

=Carl,

 

[dave roach]

Carl

You got to put the engine in the wright hands.

Dave Roach

 

[VansRacing]

Where are these hands? I want to see them.

=Carl,

 

[dave roach]

Carl

Try Rod Geraghty he would be the man.

Dave R

 

[VansRacing]

Hello Dave,

I have talked to Rod about this subject many times and the very fastest he ever got a K&B stock engine to run (using a custom made, one-off, type mini-sized tunnel boat) was 54 mph and that was not an average. That was a one way pass if I remember correctly. An average speed would be most likely be slower than this and remember, this was done on a mini size tunnel boat boat and not a race size 3.5cc tunnel.

What is causing this huge difference in performance? Is is timming, transfer, head configuration, stroke, heat, exhaust, shaft flex, back pressure, flow???? Who is interested in doing some serious testing?

I would like to see the K&B 3.5cc O/B stock engines pick up the pace and get back in the race before they are gone completely.

-Carl,

 

[waterbug]

Carl

I'm building a new ''B Sport '' Lynx with a Gearaghty K&B SX and your 1440 prop....... We will see what she will do.........

Butch

 

[jaxracer]

Hello Dave,

I have talked to Rod about this subject many times and the very fastest he ever got a K&B stock engine to run (using a custom made, one-off, type mini-sized tunnel boat) was 54 mph and that was not an average. That was a one way pass if I remember correctly. An average speed would be most likely be slower than this and remember, this was done on a mini size tunnel boat boat and not a race size 3.5cc tunnel.

What is causing this huge difference in performance? Is is timming, transfer, head configuration, stroke, heat, exhaust, shaft flex, back pressure, flow???? Who is interested in doing some serious testing?

I would like to see the K&B 3.5cc O/B stock engines pick up the pace and get back in the race before they are gone completely.

-Carl,

Maybe some of those questions can be answered after Mr. Rushing talks to that little gold headed one .

~Mitch