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Date: Tue, 15 Oct 2013 12:49:00 -0400
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From: George Braly <gwbraly@gami.com>
Subject: RE: [LML] Re: LOP ops on O-360 A1A
Thread-Topic: [LML] Re: LOP ops on O-360 A1A
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Try using some carb heat.    It will smooth out that engine significantly w=
hen LOP. =20

The warmer induction air does a much more uniform job of distributing the f=
uel as vapor with less liquid drop outs in the induction plumbing.=20


-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of vtai=
ljeff@aol.com
Sent: Tuesday, October 15, 2013 8:21 AM
To: lml@lancaironline.net
Subject: [LML] Re: LOP ops on O-360 A1A

Have you checked your baffling?

Sent from my iPad

On Oct 15, 2013, at 7:53 AM, Keith Smith <keith.smith@gmail.com> wrote:

> Hey all,
>=20
> I'm waiting for winter to come around but it seems like my O-360 A1A has =
been running warmer than usual, requiring me to power back very shortly aft=
er takeoff to avoid an excursion north of 425 degree CHT's.
>=20
> In any case, I know that LOP ops are hard to come by with an O-360 due to=
 poor fuel distribution. Indeed, my #4 cylinder peaks well before the other=
s, making it tricky to get them LOP.
>=20
> I've been running in two modes...one is around 20 LOP to cool it down to =
around 385 CHT while the others run just slightly rich of peak. I can do th=
is without much effort, and under a wide range of throttle positions, and d=
ensity altitudes.
>=20
> On a recent flight, though, I found #1 and #3 settling on temps that were=
 just too high to be happy with. I would go well ROP to get them cooled, bu=
t burned a lot of fuel in the process and still had a warm 4th cylinder due=
 to the fact that it runs quite a bit leaner. This was all done at 75% powe=
r or less, btw, density altitude was well above 11k (I was at 11k and it wa=
s +10C)
>=20
> Eventually, I tried something somewhat dramatic. I was determined to get =
ALL the cylinders LOP. I leaned relatively rapidly and ignored the disconce=
rting knocking/shuddering associated with the uneven amounts of power being=
 produced between the 4th cylinder and all the rest.
>=20
> It all happened a bit quickly, but with cylinder 1-3 roughly 20-40 LOP an=
d #4 70-90 LOP, the CHTs dropped like a stone, seemingly in seconds, down t=
o 380-385 across the board for #1-3 with #4 now in the 350-360 range. With =
careful fiddling of the mixture, and countless experiments with throttle po=
sition, I got the vibration down to the point where it was barely noticeabl=
e. Eventually it just felt smooth...but I can't tell if I got used to it, o=
r things just settled down, although I wouldn't think it was possible.
>=20
> Final fuel flow was around 8.8-9.0 gph.
>=20
> Finally, living the LOP dream with my O-360 :)
>=20
> I tried repeating this later on, down low and wasn't able to repeat it (i=
e, never got it smooth).
>=20
> So, it's elusive, but possibly doable under just the right circumstances.=
 Since I do long trips on a regular basis, I'm definitely interested in mak=
ing this work.
>=20
> Separately, I'll try to find out why it's running warmer in general. I di=
d have a mag replaced, the other rebuilt, and 4 new plugs installed in the =
last year.
>=20
> Honestly, I'm going to try to save some clams and get this converted to a=
n IO-360 (didn't realize it was relatively inexpensive until my mechanic su=
ggested it), get balanced injectors and run LOP as SOP. The difference in c=
ooling really is staggering. I know I'm probably preaching to the choir, bu=
t I thought that O-360 owners might find it eye opening. Get up high and gi=
ve it a try if you have a 4 point engine monitor. You'll know it's working =
when your leaning results in EGT and CHT's coming down :)
>=20
> The trip, btw, was N07-KFTW-KSAV-N07, around 2600nm.
>=20
> Keith

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