I think we are saying the same thing, basically and to a
degree. A dead mag does not cause a rough engine, a dead
cylinder does. A poorly balanced engine will be rough
because the different weights of the parts moving.
Different power per cylinder will be rough, but as long as
the output is close, most pilots won't notice minor
variations. I used the word misfiring to indicate what was
happening that would be detected.
Certainly, with instrumentation or skill, the pilot will be
able to detect many variations in engine operation with
different throttle positions, mixture settings and rpm.
Volumetric efficiency will vary with RPM, MAP and vary from
engine to engine. A high time engine will be different than
a new engine, carb, single point injection (pressure carb)
or port fuel injection will be different and high quality
parts are better than 50 year old OEM designs.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Thomas Borchert" wrote in
message ...
| Jim,
|
| Yes, engine roughness is caused by one cylinder
misfiring.
|
| Not at all. Or rather: very rarely. Engine roughness which
we normally
| encounter during leaning is caused by the cylinders
developing
| different amounts of power.
|
| Fuel injection is properly calibrated is the same on all
| cylinders so the engine runs smooth and balanced.
|
| TCM and Lycoming specs don't at all require that. Which is
why
| GAMIjectors are such a success. And no, GAMIjectors DON'T
calibrate
| fuel flow to be the same for each cylinder, since you
don't want or
| need that. What you need is the same fuel-air ratio in
each cylinder.
| So those cylinders that get less air need less fuel, too.
|
| Read Deakin, it's all in there.
|
| --
| Thomas Borchert (EDDH)
|