Hi Net
Well, Tweete(N110LR) is in the process of having it's engine torn down and
removed. I first flew in 1984, and currently have somewhere around 500
hours on my type 4. In 1991 shortly after takeoff I discovered that I was
using cheap cylinders to obtain 2000 cc. One failed under the head and I
made a forced landing on my home airport. I never considered the math when
I installed new cylinders. (the largest that would fit without cutting the
case, 96 mm). After the repair the engine only had 1910 cc. I have run the
engine that way for the past 13 years. I had to lap a couple of valves a
few years ago and other then trying different carbs, props and different
Ignition systems, the engine is the same. I did not have a lot of data on
the engine, only that the person who assembled it had a good reputation(BS).
I tested the engine as part of a condition inspection and found that numbers
2 & 3 had exhaust leaks and number 1 was leaking into the crankcase. As of
today I have removed the heads and pistons. I got my first look at the
insides. The heads seem ok with no obvious cracks and the valves don't
appear burned. The rings are all in tact and the cylinders seem to have
little wear. I was amazed to see that looking inside the case, through the
cylinder bore, at the cam and lifters, that the cam appears still highly
polished with no marks at all. I did measure the lift of the cam and it
lifts .317 inches and if measured correctly has a duration of about 270
degrees. The inside of the case seems to have some marks at the flywheel
end which seems to have come from contact with the last crank journal.
Perhaps my thrust bearings have worn enough to allow this scuffing. I will
continue to investigate and make a report in a few days after the case is
opened.
Orma L. Robbins Southfield MI
19 Years flying KR-2 N110LR
http://www.aviation-mechanics.com
