Ron,
In the photos I put a black mark on the aluminum tape
where I recently added the Anti-siphon port (temporarily closed off for
pressure testing) 6” from the end of the vent. The “S”
curved premolded heater hose has been replaced with a smaller ID, tighter
fitting hose for the next test. I have routed the manometer to the upper plenum
to compare between it and the crankcase vent location. I understand there should
be about 5” difference. I left a voice mail for Continental to get their
input.
Steve Colwell Legacy
Hi Steve,
Could you post some pictures of your breather hose
routing. Especially the end of the breather tube/hose where it exits the cowl.
Ron Laughlin
On 5/25/08, Steve Colwell <mcmess1919@yahoo.com> wrote:
>
>
>
> My Cont. IO-550 (normally aspirated, stock comp
ratio) is blowing
> enough oil from the crankcase breather to put a
thick coat on ˝ of
> the belly, halfway to the tail in 10 min. of
flying. Originally I
> thought I had overfilled the 8 qt. crankcase so I
drained the oil,
> changed the filter and refilled with 6.5 qts.
During runup and
> takeoff roll the manometer (tapped into the
crankcase vent about the
> mid-point of its length) will read zero until plane
has about 120
> knots indicated airspeed. At 120 to 200 knots the
manometer reads 4"
> to 5" with a short spike up to 14" to
20" when power is reduced in the pattern. The following tests have been
run:
>
>
>
> Compression test: high 60's to low 70's which I am
told is normal for
> Continentals, oil is normal color (not black, which
would indicate
> blow-by)
>
>
>
> Washed engine with mineral spirits to see if any
fresh oil was appearing.
>
>
>
> Upper plugs are normal color, maybe a dark tan
insulator, no fouling
> problems
>
>
>
> Low pressure on crankcase with 12" balloon on
crankcase vent: takes
> about 3 min to deflate, tried soap suds around all
accessible seals,
> dipstick cap, mags, pushrod tubes, etc..
>
>
>
> Relocated crankcase vent to right side cowl outlet
>
>
>
> Cut a anti-siphon hole 6" above the end of the
vent tube on normal
> left side exit.
>
>
>
> Taped the dipstick cap with aluminum tape.
>
>
>
> Put 20 psi air pressure on crankcase, soap suds
again, air going past
> piston rings, tried turning prop with no noticeable
difference from cyl to cyl.
>
>
>
> Replaced crankshaft seal.
>
>
>
> Anything that required a flight test would deposit
the same thick coat of
> oil on the belly in a single trip around the
pattern. I have just about
> run out of ideas, the engine builder has never heard
of anything like
> this and the cylinder supplier could only suggest it
could be the crankshaft
> seal. It could be a leaking seal in the
alternators or mags or ???? I
> need help.
>
>
>
> Steve Colwell Legacy 916 505-6099
>
>
>
>
>
>
>
>
--
Ron Laughlin
From: Steve\Claudette
Colwell [mailto:colwells@comcast.net]
Sent: Tuesday, May 27, 2008 7:03 PM
To: mcmess1919@yahoo.com; 'Steve/Claudette Colwell'
Subject: Here are the photos that I want to share with you
Here are the photos that I want to share with you.
I sent these photos using Adobe(R) Photoshop(R) Elements 5.0. Find out more:
http://www.adobe.com/photoshopelementswin
__________ NOD32 3137 (20080527) Information __________
This message was checked by NOD32 antivirus system.
http://www.eset.com