K&B Sleeve Mods

[lohring]

The past NAMBA record for a 3.5 modified tunnel was 58 mph, set with a mostly stock K&B on a Dumas ABS Sprint. The parts were carefully selected and the exhaust passages in the lower unit were modified. The K&B red carb had the bell mouth cut off. This shows what can be done with a carefully prepared nearly stock boat and engine. The record stood until Jimmy Johnson ran his CMB powered Lynx to 64+ mph.

Lohring Miller

 

[Jerry Wyss]

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,

Carl, Carl Carl Carl,, go look at "Races & Results", Springfield NAMBA Dist.8 Race,, second place

in "A-Stock Tunnel" is a Stock K&B Powered Boat driven by Allen Burns. That boat and motor was

prepared by Clarence Smith,,and prepared another boat and motor Lohring was talking about.

Allen was racing some Pretty Fast Competitors on this side of the Country. Clarence Smith is a

Brilliant man,,or perdy darn lucky,,several times. He's gion' in for some serious surgery, if anyone

would like to know How he did all that, I would recomend y'all put him in your prayers,,if your so inclined.

 

[Wally Marsh]

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,

Carl and others,

I fully agree, maybe I'm just stubborn. I really have nothing for or against K&B and OS in the stock/sport classes, just would like to not lose another manufacturer like K&B (and almost OS not too long ago) . Let's share ideas to keep the class alive!

the Wallster

 

[aamick1971]

steve cirmella can make a k&b run like the hammers of hell well hes got mine running great anyway!

just my 2 cents!!!!!

 

[waterbug]

Allen

What does it do without the tuned pipe !!!

Butch

 

[RodneyPierce]

Allen

What does it do without the tuned pipe !!!

Butch

I would assume it runs great without the tuned pipe, if it is a sport motor anyhow..... I dont think there is anything wrong with KB, I actually plan to stick with them! They are cheap, have been around forever, and still make a good quality product. Just my .02.........

 

[VansRacing]

I hope to see the K&B around for years to come because for one, I build a boat for the class and the more 3.5cc engines there are out there, the stronger the class will be. Even though we run the O/S engines in our IMPBA sport classes, I don't want to see just one engine dominate the class.

I personally favor the sport/stock 3.5cc class because it is a game of total setup and driver skill.

-Carl,

 

[waterbug]

I have three new K&B's and a used OS..... The OS is sitting !!!

I am working with the Lynx/K&B combo now, to see what I can get... W/C [Oval Express Racing], SS [Kevin Bulafant] , SX [ Gearaghty ].... I have not made it past the W/C engine yet !! Four props to test with each engine.. two engines to break in...

Carl you type fast and are gone !!!!

Butch

 

[VansRacing]

A couple of questions for the engine guru's out there:

Why will the stock K&B 3.5cc run 65-68 mph on a outboard hydro and the stock O/S XM is no faster?

Why does the K&B make a better modified engine than the O/S XM?

-Carl,

 

[Jerry Wyss]

A couple of questions for the engine guru's out there:

Why will the stock K&B 3.5cc run 65-68 mph on a outboard hydro and the stock O/S XM is no faster?

Why does the K&B make a better modified engine than the O/S XM?

-Carl,

You have 3.5 O/B Hydros going "65-68" regularly over there?

There is a guy over here that has a A-mod tunnel XM powered that runs perdy good,

good enough to net him first place in my last District event.

 

[GRoth265]

Carl; I run the Lynx/OS combo for my stock boat. But for my mod I have my own design WOF with a OS on a Irwin stamp pipe and the stinger to .325 dia. The only change to the motor is exhaust timing was brought up to 180 degrees. With a slightly back cut x442 the boat will run with a Lxnx/Mac combo. Eric can still cover me with his but I swear that boat is blessed. I'm very happy with this set up. This is the boat Jerry was refering to. Greg

 

[jaxracer]

A couple of questions for the engine guru's out there:

Why will the stock K&B 3.5cc run 65-68 mph on a outboard hydro and the stock O/S XM is no faster?

Why does the K&B make a better modified engine than the O/S XM?

-Carl,

As for the hydro, could that be attributed to the differences in setup, (ex. motor height, prop choice, ect.)

In regard to the K&B vs. OS being modified, I think that the main thing that holds the K&B back is the oval can and/or foot exhaust that it uses, where as the OS's exhaust can has a likeness and possibly function to that of a tuned pipe.

Also in the K&B vs. OS debate, performance comparison is largely dependent on which version of K&B that you get. The well made perfect fit one(which is rare) or the sloppy piston/liner fitted one with the burred unmatched case transfer to sleeve ported one.

Don't forget the little Thundertiger either. Why aren't they able to compete with K&B and OS? What has to be done to make them run competitively in the sport class?

~Mitch

 

[GRoth265]

Another thing to remember is in NAMBA stock class, it is a bone stock motor no mods except sharpen the fin. What you buy is what you get. Thats a huge differance from IMPBA. And yes I also believe the OS muffler seems to work as kind of a mini pipe.Greg

 

[user 115]

Another thing to remember is in NAMBA stock class, it is a bone stock motor no mods except sharpen the fin. What you buy is what you get. Thats a huge differance from IMPBA. And yes I also believe the OS muffler seems to work as kind of a mini pipe.Greg

On the OS you have to "forget" to put the head shims that come on the motor back in..

Charley

 

[Jerry Dunlap]

Re: Allen Burn's K&B 3.5

Was I the only guy at the Springfield District 8 race that noticed Allen was running a red carb on his A Stock Tunnel? I choose not to be the "Pond Nazi," but that engine is not a legal NAMBA A Stock engine with the red carb. I don't think there'd be all that much, if any, performance loss by switching to the legal gold carb.

JD

 

[Mike Hughes]

I think that the main thing that holds the K&B back is the oval can and/or foot exhaust that it uses, where as the OS's exhaust can has a likeness and possibly function to that of a tuned pipe.

Someone should take that OS muffler and bolt it to the K&B and see what they get. That thing is a big part of the OS's success.

Jerry

How the hell was I suppose to see that carb with all the rain coming down? I tell you that was the worse weather I have ever raced in. Did the 3.5 ever come out with the purple carb stock? I seem to remember this. They have the same ID. That would make it legal.

Mike

 

[Jerry Dunlap]

I never saw a K&B 3.5 come out of a box with a purple carb. Here's how I remember the K&B 3.5 carbs:

1. Black Perry carb

2. Tube carb with throttle exhaust

3. Black carb

4. Gold carb

JD

 

[VansRacing]

I think that the main thing that holds the K&B back is the oval can and/or foot exhaust that it uses, where as the OS's exhaust can has a likeness and possibly function to that of a tuned pipe.

Someone should take that OS muffler and bolt it to the K&B and see what they get. That thing is a big part of the OS's success.

Jerry

How the hell was I suppose to see that carb with all the rain coming down? I tell you that was the worse weather I have ever raced in. Did the 3.5 ever come out with the purple carb stock? I seem to remember this. They have the same ID. That would make it legal.

Mike

Mike is on it.

 

The can type mufler that K&B uses gives the K&B 3.5cc engine a little better cornering and exit torque but acts as a rev limit once the engine tries to turn up.

 

Dumping the exhaust in the side of the can is killing the top end. If K&B would just take the can they are currently using, turn it 90 degrees, dump the exhaust in one end and stinger other end, they would at least be closer to what is needed to run with the O/S.

 

The K&B will come alive once this is done but it will have to be done by the manufacturer in order to run it in the stock class. If I were running K&B engines, I would be calling K&B and wearing their ears out about it.

 

-Carl,

 

[waterbug]

Who are the factory reps ??? Who do we talk to ???

Butch

 

[Kris Flynn]

Carl and others, I am working on an adaptor plate for my Geraghty w/c 21 K&B

I will make it fit a K&B leg so the test will be as close as possible to a direct comparison to the 'sport' K&B chamber in the K&B leg to the OS muffler

Cheers

Kris