tommayer wrote:

Paul, Bill,
    Is Lenkite BS too?  I've been using it, at unsemmly cost, as a
prophalactic against valve sticking in Lycs and P&Ws, and have not have

any

trouble since using it, but I keep thinking that's just how the ball has
bounced for 1500 hours or so.  Tom Mayer

I never heard of it. That valve sticking problem is a toughie. Lots of
theories around on what causes it. According to John Schwaner of
the Sky Ranch Engineering Manual fame it is caused by high temperatures
in the exhaust valve guide oxidizing the oil. Seems to me a good
high temp synthetic would help. Tom, please test some of the oil you are
using in your oven at 500 F and let us know how it works out.

John also says keep checking your valves for leaking. A leaking
valve runs at a higher temp and is more likely to stick.

I am sure glad we don't have exhaust valves in rotaries :-)

Paul Lamar

tommayer wrote:

Paul,
    Sticking valves are endemic on Lyc powered spray planes. Usually happens
on number one.  People who know more than I do say the reason is a lot of
quick cooling.
    Av-Blend, like Microlon, is FAA approved.  That of course only means the
FAA does not think it will hurt anything.  If I understand, it is a top end
wetting agent.  They put it in an auto product called Z Max.
    I have used it with good success to free stuck valves on R-985s and
1340s, and on a TIO-360 so prevent problems.
    Lycoming makes an additive called LW-16702 that is supposed to do the
same thing.  Long ago somebody put on the site an article saying no aircraft
manufacturer makes or recommends an additive, which is patently not so.  I
believe both Shell 15/50 and the new Exxon semi-synthetic are supposed to
contain the active ingredient, whatever it is.  Tom Mayer

You ought to take those Lycs out of the spray planes and get an STC on a 
three rotor. If they did it on the Chezk PT6 copy you should be able
to do it with a three rotor :-) You might need a six pinion planet carrier
in Tracy's redrive. (In the works.) 

Paul Lamar

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