IO 360 Power down (danger, long, rambling post!)

"Jim Harper" wrote in message
om...
Hi, group. I've come to this august assembelage of persons to ask for
ideas, and to discuss a few of mine. I am the proud owner and flyer of
a lovely, new, RV 8A. Alas, I am not the builder, but as I am sure you
know, owning one begins the process of working with one...

At any rate, we have around 135 hours on this machine. Engine is an
IO-360-A1B6 with one Plasma ignition, one Bendix mag, Gami injectors,
Aero Composites CS prop, stock Van's intake with K&N filter on the
left front baffle shelf. Since the airplane started its flying life,
itsbeen power down. The engine is one of those Bulldog engines
imported from England. It has around 900 hours total, and is fresh
(just before installation) off of an overhaul. Compressions are fine,
plugs look good and I am taking good care of it.

Van's says a 200 horsepower RV8A will cruise at 210mph at 75% power at
8000 feet. Book says it will climb at 2500 fpm at 1500 pounds.

Mine cruises at 182mph and climbs at 1800 fpm. Now, nothing wrong with
that performance, but still and all...The airplane is straight and
slick. No unusual drag makers. It would seem that I am missing around
25 or so horsepower.

snip

Any of y'all have any OTHER suggestions? The intake manifold would
look to be OK, no holes or the like.

Thanks for sharing my quandry.

Jim

How about a bad camshaft or follower? You could pull the valve covers and
plugs, then rotate the engine by hand and measure the movement of the rocker
arms to see if you have a worn cam lobe or follower. This is a simple way
to determine if there is a valve that doesn't get the same lift as the
others...

By the way, do you have RPM and MP data on the engine? Are you gettting the
reduced performance you quote when running at 75% per the lycoming
rpm/mp/temp charts?

Is it possible that your tach is off or your MP is low because of a clogged
air filter or some other induction problem?

KB