Old Konig "can"-type tuned exhaust

[smittythewelder]

In the final years (mid-'60s) that Konig manufactured the two-cylinder FB engine, it was delivered with a tuned exhaust that was, IIRC, a two-into-one pair of elbows terminating in a simple shallow-angle megaphone, which was enclosed in a big muffling "can" with a short outlet pipe. The early rotary-valve fours later got a similar system.

If anyone has a dimensioned drawing of the various parts of the FB "can" exhaust, I'd like to see it.

[Master Oil Racing Team]

I have dimensions on the 4 cylinder Smitty which can be found posted in my BALDY story, but I am not sure I have the FB dimensions. I'll take a look when I get caught up and post it if I do.

[smittythewelder]

Thanks, Wayne. And I really don't have to have a drawing, if you or anyone can find the dimensions.

As I recall seeing the four-cylinder "can" (a big ugly thing, I thought), it had a sliding section. The can was restrained in aft-wards travel by a length of wire cable, and you could fix the assembly within about a 3-4" range of in-out travel. I don't recall whether the "can" on the late FB was adjustable in that way; there were almost none up here. Barry Lewis' dad welded him up a set of early expansion chambers for his FB; the few other guys with FBs used megaphones. I think it was Roy Heagy, maybe, who had a "can" on his FB. He also was, I think, trying pistons and rings from the Kawasaki 500 triple when the FB pistons could no longer be obtained; the Kaw pistons weren't ideal, because the cutouts in the skirt didn't line up too well with the FB transfer ports, but at least they kept the engine useable.

The factory exhaust for the Yamato 80 (and possibly the more recent Yamato stockers, about which I know nothing) was rather similar in principle.

[Bill Van Steenwyk]

Smitty:

Try Steve Litzell in Atlanta. Steve has lots of information about the old Konigs, and even some parts for them. He is also the distributor for VRP and Konny. He is here on BRF and also HR and would probably answer a PM if he does not see this thread.

You are right about the can having several positions you could put it in. Like the pipes, all the way up for for top RPM and all the way back was for acceleration. I never saw anybody try to slide one like the pipes worked later, but possible they did. The adjustment was with the cable tie, and you put it where you wanted it by adjusting the cable length.

Still have a nice burn scar on my left outside bicep from getting too close to one while helping a guy carry his boat out of the water. Never will forget that sound of my flesh sizzling, and just putting up with it, because I did not want to drop the boat and damage his prop or break a skeg on the unit.

Bill

[smittythewelder]

Just PM'ed him, thanks.

[Master Oil Racing Team]

I don't have the FB can schematics, but seems like I have seen one somewhere. I'll keep checking.

[smittythewelder]

Steve Litzell was kind enough to give me a written description of the inside of "the can," rather different from what I thought: no megaphone, but with an interior baffle plate and four tubes moving the pressure pulses back and forth before exiting. Steve says that not only was there the "early" can for the FB, but there was a "late" can for another engine.

This from the PM that I sent Steve:

"The project is to make a "playmotor" out of an engine that's not much good for anything else. This is a Yamato 80 that was going to be a Restricted B. The stock tower was cut down to lower the engine, and I never had the other exhaust parts so I made a 2-into-1 elbow and adapter plate. I built sliding expansion chamber and bracket, but for a playmotor I'd rather have something more compact and quieter, such as that old FB can. I never had an FB, but guess that the exhaust-open timing of a factory FB might have been pretty close to that of this particular Y-80, which is at a conservative 97 degrees after top center. I'll try to use the stock pistons and rings, and not rev the engine so high as to float the rings. Maybe I could help that aspect by drilling the little pressure-holes in the piston crown that were popular in some kinds of racing for a while. Maybe they'd plug up too quickly; this will probably just be a gas-and-oil engine, with no methanol component. I'll leave the head volume alone except for trimming the squish to around .035". I'll bore the stock Y80 carb 2mm, and use the stock reedblocks.

I hope to end up with a mildly-modified Y80 that doesn't make a lot of noise and isn't peaky or touchy, that will let guys get their first ride in a hydro, and go maybe 70mph. It also will be MY first boatride since way back when, so I can get an idea whether at age 67 my old eyes and bod will let me get on a racecourse again some time.

[smittythewelder]

Well, things have come up that mean I have no time to spend here. Thanks to all.