Does the Aerokroil version cost ten times more?
PB Blaster is another excellent penetrator. Somtimes if you can get
the engine to run that can get them loose. A 13B will run with only
one rotor face. Turn the engine over to line up each apex seal with
the exhaust port and you can push on the each apex seal with a
screwdriver and see if they move. Spray penetrant directly, strike
with a punch, heat with a torch, all are options.
Francois, I hope this is a area of concern for you guys, considering
how few hours many planes are flown. I would hate for your (our)
engines to get a bad rep for something so simple. I have seen this
phenomena a LOT in the cars. I have always been intrigued by the
Hurley idea of feeding oil straight into the apex seal slot, but still
haven't actually implemented it on any engine I have built. It seems
to me that this lubricates the apex seal slot better than any other
method. This and/or two stroke oil in the fuel and/or ceramic apex
seals could mean a much higher TBO than you are shooting for IMVHO.
Is
Mistral going to go with ceramic apex seals? I'm thinking that
ceramic
apex seals would not be prone to sticking.
Hans Conser
Network Chiropractor
Hans,
This seal sticking stuff is obviously of concern to us, although we
haven't had any problem so far... but our engines are far from having
thousands of hours. As a commercial product aiming to be certified, we
CANNOT ask our clients to mix 2-cycle oil with the gas, it's simply
impractical. A separate oil tank for the sacrificial oil might be a
solution but with marketing and safety drawbacks (what if an idiot fills
the respective oil tanks with the wrong oil?). For the moment, we are
experimenting with various oils and talking to oil manufacturers to come
with the best possible single all-around oil.
We are also considering ceramic seals, but they are 5-6 times more
expensive than regular seals... we may offer them as an option, we'll
see.
We'd love to have feedback from somebody who tried the Hurley method of
feeding oil directly to the seals through tiny holes in the rotor.
Francois Badoux
Francois,
I was wondering about that also, but I've seen that on housing I thought
were on late model genuine Mazda rotor housings (as well).
Paul suggests that the direct injection ( one hole to the centre) was to
also cool the apex seal whereas the Renesis [RX8] has two holes designed to
primarily to lubricate the apex side seals (and uses less oil), because the
apex seals were running much cooler..
George (down under)
Francois
What to ceramic apex seals cost? $300??? It seems like such a small price
to pay for protecting all the fine work you done.
Doug in Japan
They are two hundred each. About $1200 for a set of six. Supposedly the wear
rate is so low nobody has been able to measure it yet. Projected life
in a gen set running at 3600 RPM is 20,000 hours. Which by the way whips
all turbine engines. And I don't think they were even using Mobile One.
BTW This is a very significant advantage over a piston engine as it is not
possible
to build piston rings out of silicon carbide.
Paul Lamar
Owwch. So that makes it $1800 for a 20B. Perhaps I should be in the
ceramic seal business:)
Doug in Japan
I have been looking for another supplier. Go for it :)
I think they are made in Japan anyway by Kyocera.
Paul Lamar
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