A week or so ago while helping install a new $36K IO360
Continental on a 182, I had a thought about our engines- and
although I did think of how many rotary engines could be bought for
36K, that isnt what this about.

The connie had a Y in the intake with a spring loaded split
butterfly that provides automatic alternate air in the event of a
primary intake blockage. While looking at this, it hit me...

If we used a regular off the shelf holley carb or if you prefer a
side draft carb of some version why couldn't we just add an extra
butterfly, smaller, that lets in air around the carb to lean the
engine? Run a hose to the air cleaner and that's all there is to
it.

This way the carb jets could be set for max power plus a little
rich for cooling, and we just connect a vernier cable to the other
butterfly to lean the engine. Air that doesn't go through the carb
would cause a lean condition just like any other induction leak,
and the remedy is the same- plug the hole.

Simple, effective, idiot proof. If the engine starts to skip or
run rough, push the red handle in and you are back to mixture
baseline. No altering mixture by changing jets, etc. Easy.

Kevin Alderman


I think that would work.

One of these days I am going to work on my side draft slide
throttle Holley :) Maybe when I get the turbo compound engine
done.

Paul Lamar


Hey, I posted this idea a while ago. I'll expect a royalty cheque in
the mail
Everett Rankin


Yes you did Everett. Here it is. Good luck on the royalty check :)

People, me included, have occasionally hear an idea and then file it away
in their subconscious and then it appears later and they think it is their
own idea.

However I don't think Kevin was on here then.

Paul Lamar

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-------- Original Message --------
Subject:     Possible method of leaning Weber carbs
Date:     Thu, 23 Jun 2011 01:13:59 -0500
From:     Everett Rankin <emgrankin@gmail.com>
To:     AAA Put this in the To box <rotaryeng@earthlink.net>



So I've been thinking, it seems that nearly everybody with EFI has
serious tuning issues which makes a carb sound more and more
attractive.  I know Paul has drawn a Holley setup on the website and an
off the shelf leaning solution id available but the Weber DCOE just
packages soooo much nicer on the rotary, especially with P ports.   We
already know it runs well and makes tons of power on the dyno so the
only problem is a workable leaning system for cruise.  I had the
thought, instead of trying to alter the fuel flow why not alter the air
flow?  Why not install taps into the runners (or the housings) teed to a
cable operated ball valve which bypasses the carb;  basically a
controlled vacuum leak.  When the ball valve is opened it would allow
filtered air to bypass the carb reducing the signal to the venturis and
causing less fuel to be drawn.  Sizing would probably take some trial
and error but once sorted it should be dead nuts reliable.  Is there any
reason this wouldn't work?  What am I missing?

Everett Rankin


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