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
