Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Tue, 03 Jun 2003 16:54:25 -0400
Message-ID: <redirect-2400904@logan.com>
From: "Gerry Leinweber" <gerry@doctorseyecare.ab.ca>
References: <list-2371675@logan.com>
Subject: Re: [LML] Re: TSIO 550 Rich or Lean of Peak?
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Thanks for all who have responded on this question to date.  First, here are
the more complete numbers off our VM1000 when we have run 50 ROP as
recommended at Lancair by one of the chief training pilots (Grant I believe)
the day before he left for new challenges last year.

Climb: Full Rich, Full Throttle, low boost on for 1st 1000 ft, we have a
fuel flow of about 39 gph and then after the 1st 1000, it is 31" and 2500
RPM for the rest of the climb.  Fuel flow remains in the high 30's and I am
not 100% certain of CHT and TIT but promise to monitor closer in the future.
In cruise, at 28" and 2400 RPM, leaned out to 50 rich of peak, we are
getting fuel flow of 19.5 gph and TIT of 1630 and max CHT of 380.  I am
getting the impression these temps are too high.  Comments would be
welcomed.

Now, I have read much of the material recommended, and here is some
information on the issue which I am sure will stimulate debate.  Based on
the fact I have heard conflicting opinions, I had a talk with Dave From, the
local aircraft engine rebuilder with over 35 years experience with Pistons.
Dave pulls no punches, but I have edited out some of his more colourful
language.

First, he agrees with the comment that the cooler the heads are, the longer
your engine will run without needing a top end. He also likes the idea of
keeping temps down by using the fuel flow meter as the primary instrument to
get to the final operating temperature quickly. Up in Canada, I can figure
on budgeting $8000 for a top end job and with the TSIO 550, I will bank on
the fact I will need it within 300 - 500 hours.  Dave has seen a lot of
turbo charged engines which were run lean of peak and they tend to burn
valves and guides earlier than in engines which run 75 to 100 rich of peak,
which is what he recommends.  Pay for the gas, or pay for the top end
earlier, and perhaps another top end before TBO is how Dave sees it.  You
have to know him to understand Dave, but this obviously is his honest
opinion as he does make his living rebuilding engines, not selling gas, yet
he advises you to run rich.  Not wanting to offend any writers of this
forum, I won't repeat what he said about GAMI injectors, suffice it to say,
he does not recommend them due to problems he has seen in engines that
installed them, ran lean of peak and burned out valves and guides early.

However, it sounds to me that I will be doing a top end soon anyway, whether
I run Rich or Lean. If I run lean, I will save likely four gallons per hour,
and get better mileage out of a tank of gas on a cross country trip. I am
intrigued by the fact leaner is cooler, and cooler is usually better. I have
not made any conclusions yet, but am now seeing both sides of this debate
more clearly and it sure is a learning experience.  I do think I will be
changing the way I manage the engine, just not sure I have seen the proper
"double blind study" to confirm what the facts are both from an economic
point of view and from a reliability perspective.

Gerry Leinweber C-GLFP