Lycoming 0-290
Bill Divens
Quick question:
What is the TBO of a Lycoming 0-290-D2 with the 7/16 valves? The
1/2 inch valves take the TBO to 2000, but the smaller valves make it
either a 1500 hour or 1200 hour TBO. I'm not sure which.
Bill
erco...@pitt.edu
Gregory Travis
In article <34F2FFE0...@pitt.edu>,
1500 hours
Ref: http://www.prime-mover.org/Aviation/Manuf_Page/si1009ak-2.html
greg
John R. Johnson
The 7/16 valves were the first large stem valves in the O-290. The
original valves were 3/8 and had a 1200 hour TBO as I recall! The
"large" 7/16 stems increased the TBO to 1500 hours. Later, they still
had some problems with valves "necking" and breaking in flight and they
increased the stem diameter to a full 1/2 inch. That seems to have fixed
the problem. I don't know of a case of valves necking down and losing
their heads with the 1/2 inch stems, although I do know of several with
the original 3/8 inch stems.
John
On Tue, 24 Feb 1998, Bill Divens wrote:
> Quick question:
>
> What is the TBO of a Lycoming 0-290-D2 with the 7/16 valves? The
> 1/2 inch valves take the TBO to 2000, but the smaller valves make it
> either a 1500 hour or 1200 hour TBO. I'm not sure which.
>
> Bill
> erco...@pitt.edu
>
>
>
>
Bruce A. Frank
John R. Johnson wrote:
>
> The 7/16 valves were the first large stem valves in the O-290. The
> original valves were 3/8 and had a 1200 hour TBO as I recall! The
> "large" 7/16 stems increased the TBO to 1500 hours. Later, they still
> had some problems with valves "necking" and breaking in flight and they
> increased the stem diameter to a full 1/2 inch. That seems to have fixed
> the problem. I don't know of a case of valves necking down and losing
> their heads with the 1/2 inch stems, although I do know of several with
> the original 3/8 inch stems.
>
> John
Wasn't there also another problem with lead fouling of the smaller
diameter guides causing the valves to stick frequently? I have been
under the impression, from years of reading the Short Wing Piper News,
that going to larger stemmed valves significantly reduced this stuck
valve problem.
--
Bruce A. Frank, Editor "Ford 3.8L Engine and V-6 STOL
BAF...@worldnet.att.net Homebuilt Aircraft Newsletter"
| Publishing interesting material|
| on all aspects of alternative |
| engines and homebuilt aircraft.|
*------------------------------**----*
\(-o-)/ AIRCRAFT PROJECTS CO.
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/ \ for homebuilt aircraft,
0 0 TIG welding
While trying to find the time to finish mine.
Clara pegg
In some of the old 1970's issues of EAA's mag, Sport Aviation, there are
articles about the O-290G. The "G" denotes that the engine is a ground power
unit. It was designed for running at 1800 r. p. m. When homebuilders began to
use these engines in their aircraft and turned them at 2400 r. p. m. another
problem besides cracks, broken cranks, and stretched valves plagued them. The
lobes wore flat on the cams. Why? Because the cam lobes were not as wide as
those on the aircraft 290's and, if I recall correctly, the lobes were not
angled as in the O-290D to cause the lifter body to rotate and assure uniform
wear across its surface. So the lifter bodies, which in the aircraft version
also had a crown of a degree or so, developed a typical wear pattern showing
that the lifter body was not rotating. This is not to say that the O-290G
should not have been used in aircraft, just that the problems that come with
turning a ground power unit at 2400 r. p. m. should be understood. I have
taken many a safe ride in a Stits Playboy with an O-290G powerplant and
enjoyed every minute of it.
There are other usenet postings on a "rare" engine. Some engines are rare
for a purpose: they are not worth fiddling with, except hanging on a stand
somewhere for display. Such engines are the Lycoming geared engines like the
GO-300, the Continental engines like the Tiara and the O-300, maybe the E-185,
which requires ridiculously expensive silver alloy main bearings at bottom end
overhaul time.
John R. Johnson
On 24 Feb 1998, Clara pegg wrote:
<snip>
> There are other usenet postings on a "rare" engine. Some engines are rare
> for a purpose: they are not worth fiddling with, except hanging on a stand
> somewhere for display. Such engines are the Lycoming geared engines like the
> GO-300, the Continental engines like the Tiara and the O-300, maybe the E-185,
> which requires ridiculously expensive silver alloy main bearings at bottom end
> overhaul time.
Hmm. This is an interesting list. The GO-300 is a geared engine, but was
not made by Lycoming. A Lycoming GO-300 would indeed be rare! :-) Actually,
the GO-300 was a geared version of the Continental O-300 that was used to
upgrade the performance of the ubiquitous C-172 . The upgraded version was
called the C-175 Skylark and was quite successful until Cessna dropped it.
The geared engine did cause problems for folks who learned to fly with the
also ubiquitous Continental A-65. They kept abusing the gear train to
"baby" the engine and the overhaul costs went up. Since there were never
many GO-300's built some of the unique parts are rather expensive. Most
of the parts are the same as the O-300 with was one of the most popular
aircraft engines ever built, used in thousands of Cessna 172's, as well as
many other four place aircraft in the forties and fifties.
The Tiara was never used by a manufacturer, only by a few homebuilders.
The E-185 was a nice engine, that grew up a bit and had a few improvements
added and eventually became one of the most popular aircraft engines also.
Nowadays that engine is known as the Continental O-470 and is used in all
kinds of airplanes, like Cessna 182's, C-180's, Bonanzas, Luscombe Sedans,
Beech Barons, and other rare and unusual aircraft! :-)
Actually, many C-172 owners will tell you that the Lycoming engine in the
Cessna 172 was NOT an improvement. It was dictated more by the fact the
Cessna and Lycoming were owned by the same conglomerate than by engineering.
John
Gregory Travis
In article <Pine.SOL.3.91.980225092141.24396N-100000@reliant>,
John R. Johnson <jo...@siu.edu> wrote:
>The Tiara was never used by a manufacturer, only by a few homebuilders.
The Tiara was certified and went into two production aircraft: The Piper
Pawnee Ag-Plane and an Avions Pierre Robin model (that I forget, was it
the Jodel?).
>Actually, many C-172 owners will tell you that the Lycoming engine in the
>Cessna 172 was NOT an improvement. It was dictated more by the fact the
>Cessna and Lycoming were owned by the same conglomerate than by engineering.
Cessna and Lycoming were NOT part of the same conglomerate when Cessna
chose the O-320-E2D for the 172. Lycoming was part of AVCO at the time
and Cessna was an independent business.
Lycoming sold Cessna on the O-320-E2D for the original Cardinal C-177. Back
in those days, the airframe manufacturers committed to thousands of engines
in a single buy. Cessna's testing indicated that the 150HP O-320-E2D was
NOT going to be powerful enough for the C-177 (even by Cessna standards,
which basically means they couldn't get it to rotate speed on a 10,000'
runway :-) ). However, Cessna already had bought thousands of
-E2Ds and didn't feel like just throwing them away. So they retrofitted
the C172 to take the -E2D and the rest is history.
I have the above, in nauseating detail, at:
http://www.prime-mover.org/Aviation/C172.ENGINES.html
John, I think you forgot your cup of coffee this morning! :-)
greg
John R. Johnson
On 25 Feb 1998, Gregory Travis wrote:
<snip>
>
> I have the above, in nauseating detail, at:
>
> http://www.prime-mover.org/Aviation/C172.ENGINES.html
>
> John, I think you forgot your cup of coffee this morning! :-)
>
> greg
>
>
John