In a message dated 8/11/2006 7:20:55 P.M. Central Standard Time,
glcasey@adelphia.net writes:
Do you have enough data to
allow one to reconstruct the timing algorithm of the Lightspeed
system?
Gary,
Enough to know the normal ranges to expect as I noted.
For most of the normal operating range of NA engines that have lower CRs, 25
DBTDC, + or - a bit, is fine (let's say for 65-85% power). EIs will
advance the timing when the power is reduced below 75%, frequently this is
beneficially seen as the cruise altitude goes higher - 10,000 - 12,000 -
15,000 MSL cruise operation (since the cruise RPM probably is a
constant, but the MAP decreases).
Have you used a timing light to check the advance of individual
cylinders to see if the advance is being computed equally for
all?
Hey, I only have 4 and two of them have been checked while the
other two should match cause of the waste spark logic.....
Just curious, as in my system for a 6-cylinder system I see a
few unusual indications. For example, one EGT consistently runs higher
than the others by maybe 40 degrees, but this is only with the LSE
on.
Hah. Have you considered a bad ign wire? bad
plug? Bad connection to the plug? On the EI side only, of
course.... I must assume that if you can turn off the EI, you have some
12th century device backing up the ignition - like a mag. I would expect
that a mag-fired half an engine would run totally different than the EI
half since the timing and spark energy may be different.
When running on the other side (magneto) the temperatures are
very uniform.
Yes, the F/A mixture and spark may be just right.
Perhaps your engine, and the mag spark, fuel supply, and air may be better
suited for x degrees BTDC. Perhaps the engine would run better with 2
mags. Perhaps......
I had a failure of the LSE after about 30 where I heard a
distinct combustion knock for a few cycles and then the EGT for 2 cylinders
from two different channels went up by almost 100. Then all EGT's went
up and became uniform - that's when it blew the fuse and I was running on the
mag alone. Klaus fixed it just fine and it's been running good since,
but that's only been a couple of hours. Another odd thing is that since
it was repaired I have 3 cylinders that run about 40 higher than the others,
3,4 and 6. 3 and 4 are the same channel. I'm nervous about the
ignition timing not being uniform from cylinder to
cylinder.
Did Klaus explain what was wrong? Generally, EIs raise
CHTs and lower EGTs because of the more complete combustion in the
cylinder. There are many possibilities.
Anyhow, as I understand it, there are 2 timing events per
revolution. The computer calculates when to start firing from those two
events. If the events do not always occur because the magnets/sensors are
not quite spaced right, the marks can be missed and timing errors can
occur. 4 cylinders are so simple............ But, there are other
conditions to consider - bad plugs, bad wires, bad connections, bad grounds, etc
- on the EI side. The same problems can occur with mags although from your
description, the mag seems to be fine.
I have no problems running a dual LSE EI with the crank sensor
on a lyc engine.
It is very difficult to debug ignition problems
when there is a mix with EI and mag as the mag (or the EI) may cover the
failings of the other.
To go down another path, if I
over prime my engine, I get a horrendous backfire on start-up because of the
EI waste spark system and the fact that even a cylinder due for an exhaust
stroke has been filled with fuel - thus a competing explosion (uh,
burn). What happens with continuous fuel injection and bad valve
overlap? I dunno.
Scott Krueger
AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL
(KARR)
Abnegate
Exigencies!