Sender: <marv@lancaironline.net>
To:  lml@lancaironline.net
Date: Wed, 09 Sep 2009 12:07:06 -0400
Message-ID: <redirect-3842882@logan.com>
Received-SPF: none
 receiver=logan.com; client-ip=24.196.78.220; envelope-from=Tim@5000feet.com
From: Tim Olson <Tim@5000feet.com>
User-Agent: Thunderbird 2.0.0.23 (Windows/20090812)
MIME-Version: 1.0
Subject: Re: [LML] HELP! Lightspeed ignition problem
References: <list-3842577@logan.com>
In-Reply-To: <list-3842577@logan.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: quoted-printable

Fred,

This is way off the wall but, I've posted stuff recently about
LOP ops here and will be reporting back after all the
awesome replies I had...just waiting on a little more data.
But, let me tell you what we found as part of that little
extravaganza.

The RV-10's in question that couldn't run LOP all had
one common feature....the Sam James Cowl, with round
inlets.  They all needed to swap injectors from .028 size
down to .025 or .026 as a start, and that improved things
a bunch, giving probably better pressure and atomization.
But, the story really took a twist too.  They noticed
a little fuel leaking out of their #2 injectors...the
one facing closest to the incoming wind.  On the LML,
I had seen references to pressurizing the plenum or injector
manifolds and we correlated this a little to some of the
possible things.  One guy decided to try putting a little
air dam in front of the injector to block airflow from
hitting it directly.  Weird, but it improved things
quite a bit.  The air must have been flowing by the
injector and causing some low pressure.  Another guy
tried the same thing....and the same result.  We thought
it could have been many many things...timing, compression,
or whatever, but in the end it looks like some major
things are caused just by the cowling airflows.

So perhaps you are experiencing something of that nature?
Maybe building a temporary wind block of some type would
help you determine that?

I know, I know, it's off the wall, but....

Tim

Frederick Moreno wrote:
> Major hair loss and frustration arising from an intermittent,=20
> persistent, and worsening problem with my Lightspeed ignition on my=20
> IO-550.  (Magneto on second  system.)  Any help or guesses would be=20
> greatly appreciated.
>=20
> =20
>=20
> The Problem: bad missing on run up when running Lightspeed only. =20
> Missing in No. 1 cylinder, when it occurred, which is irregular.
>=20
> =20
>=20
> Here is where it gets weird: It only happens when the plenum and cowl=20
> are on.  Plenum off: no problem,  Plenum on, sometimes a problem.  Toda=
y=20
> no problem.  Put plenum and top cowl on: big problem, lots of missing o=
n=20
> no. 1 cylinder (not number 2) as evidenced by rapidly rising EGT during=
=20
> the missing.
>=20
> =20
>=20
> That would seem to suggest cooling air flow is wiggling something=20
> around.  If so, we have not found it yet.
>=20
> =20
>=20
> What we have tried:
>=20
> =B7         Switched ignition coil for 1-2, put in new.
>=20
> =B7         Switched plug lines between 1-2
>=20
> =B7         Switched spark plugs.
>=20
> =B7         Substituted new high tension line for  cyl 1.  Seemed to he=
lp=20
> until we put the cowl back on.  Problem resumed.
>=20
> =B7         Ran timing light (cowl off) on all spark plugs, got good cl=
ean=20
> signals, but then  there was no missing with the cowl off.  We may want=
=20
> to  try again with cowl on and run the  timing light wires out somehow.=

>=20
> =B7         Checked timing against spec, got good steady consistent=20
> signals from the timing light, but again, this was cowl and plenum off.=

>=20
> =B7         Rerouted all primary and secondary leads with separation fr=
om=20
> each other and from ground surfaces.=20
>=20
> =B7         Checked all  possible places where wires might rub or  wigg=
le=20
> due to cooling air blast when cowl is on.  Secured all lines with lots =

> of tie wraps to prevent wind driven wiggles.
>=20
> =B7         Rerouted all suspicious secondary lines keeping them well=20
> clear of everything.
>=20
> =B7         Tied all lines down to restrict possibility of wires floppi=
ng=20
> around under the cooling air blast when cowl is on.
>=20
> =20
>=20
> Right now, the only really definitive data is:
>=20
> =B7         Missing only occurs when cowl and plenum are on.
>=20
> =B7         Missing is in cylinder  1, NOT 1 and 2 at the same time.=20
>   That suggests a secondary wire fault, but substitutions yielded no=20
> improvements.=20
>=20
> =B7         All plugs are new (fewer than 5 hours) and appear clean and=
 new
>=20
> =20
>=20
> There is only one thing we have not tried (we think): My Lightspeed box=
=20
> is mounted on the front of the firewall, inside of a fibreglass box to =

> which is routed a 1 inch SCAT line that directs cooling air from above =

> the engine into the box and into the little cooling air port  that Klau=
s=20
> puts into his six cylinder ignition systems.  Theory: cowl on, lots of =

> air flow, something is happening inside the box that somehow affects cy=
l=20
> 1 (but not two, which is a mental puzzle as there is only one primary=20
> line from the box to the coil for cyls 1-2).  We will try again tomorro=
w=20
> with the cooling air blast tube connected and then disconnected and see=
=20
> if we can find any change, and then it is time to dig into the box.
>=20
> =20
>=20
> We are really grasping at straws here, and have a pile of straws severa=
l=20
> feet high that yielded no results.  Any suggestions or speculations=20
> welcome.  We may have to hire a mechanic with psychic powers.
>=20
> =20
>=20
> Frustrated Fred
>=20
> =20
>=20
> =20
>=20