> << There is no pressure to speak of on these o-rings with a properly vented
> oil sump system. They are mainly there to seal the rotor housing from oil
> seepage when the engine is stopped. Only a limited amount of oil is trapped
> in the rotor when the engine stops. It is this trapped oil they are
designed
> to seal from seepage down into the rotor housing cavities. The oil O-rings
> are
> above the top of the oil level in the sump when the properly installed up
> right rotary engine is stopped so no oil touches these o-rings.
> When they failed in my Cosmo the smoking stopped in a few seconds after
> startup and no abnormal oil consumption was noticed by me.
> In this regard the engine acted a lot like a radial engine.
>
> Lynn I am sure you have had some experience along these lines.
>
> The two metal oil seal rings do all the oil scrapping while the engine
> is running.
>
>
> Paul Lamar
>
> I had a disabling "O" ring failure after running the same engine for three
> years with oil temps of 230+. I ran the engine at home with no problem. We
> took it off the trailer at Indianapolis Raceway Park and it started smoking
> big time. I thought I might have mixed too much oil or mixed it twice over
> the two weeks between races. I ran it on fuel with no oil at all and it kept
> getting worse. I mean big white clouds of smoke like W.W.II. We went home.
On
> inspection, I found the "O" rings on the front side of the rear rotor had
> decomposed into pieces about 1/2" long. There was little wear on anything so
> I replaced the "O" rings and put it back together. Since it is unlikely that
> both "O" rings failed at the same time, (we may have been running for some
> time with just one ring working) I have wondered if I could get away with
> just running the inside scraper and do away with some drag. Also I notice
> that the center hole in the iron could be larger, and maybe the single
> scraper with less spring pressure would be more effective. The scrapers have
> to deal with all of the oil expended from each bearing and the oil spray
> holes in the crank. This, and a big centrifugal load on the oil. Since we
got
> the oil temp down to 190-200 we have had no additional problems.
> Lynn E. Hanover.
I forgot about the centrifugal oil load on the oil rings. Very good point
Lynn.
Thanks for bringing that up.
BTW I just bought some O-rings for the wiggins coupling from McMaster
Carr. They did not have the size and material I needed in the catalog but
they got them to me anyway by UPS Red Label. So I think we can get the
teflon encapsulated silicone oil control o-rings from McMaster Carr as well.
The size I think we need for the outer ring is 4 3/4 ID 3/32" section
which should have an AS568A-158 number. The inner ring should be
an AS568A-157. That would be a 4 1/2 ID with a 3/32" section.
I could be wrong on this. Tom Kimsey has a set so we shall see.
I think we can up the temperature of the oil going into the engine out of the
oil cooler to 250 degrees F if these 500 degree F oil O-rings are used
and are successful.
BTW This is the oil temp Continental used on the Voyager engine the
Rutans used to fly around the world non-stop in 216 hours. Patrick Swayzes
Cessna 414 with water cooled turbo Continental six's also, I suppose, use
this oil temperature limit. The benefits are less heat loss to the oil,
less fuel consumption and a smaller oil cooler hence less cooling drag.
The stock gen II oil cooler would then be more than adequate for over 200 HP.
Paul Lamar
Jean Fouche wrote:
Paul
In your opinion and experience; which fails the soonest - outer or inner oil
control o-ring?
I have no idea Jean. Bruce Turrentine might be able to answer that as he has
overhauled many engines.
Paul Lamar
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