"The first one came from a recycling yard and the second from a
sports cars maintenance and repair garage.  The first engine was
purchased on May 28, 1987, without any warranty. The sellers did
not know what its condition was and frankly told me so.  It ran
very well and produced very good power.

I ran it many hours on the ground and at 1 hour 50 min air time,
while ground running at full power (4800 rpm) it emitted a very
loud noise much like an explosion and went instantly into a very
pronounced shaking and wobbling. I do not remember any warning
signs from the engine, prior to this failure. It would still
start easily and run at idle, but the shaking and wobbling was
so pronounced that I removed it from the aircraft and bought the
second engine. 

As I did not open the first engine, I do not know what the
damage was, but while taking the carburetor off, I noticed that
I was short of a 3/16-inch steel spring washer. As I had opened
the carburetor several times on the engine, while tuning it, I
concluded tentatively that the washer had dropped into the
intake manifold unnoticed and been sucked inside the engine at
high rpm. I do not know what damage a 3/16-inch spring washer
can do, but I suspect that it can break up apex seals and/or
gouge the rotor housing inside walls. 

 I credit that first engine with 1 hour 50 minutes air
time, but until now I neglected to consider that between May
1987 and Oct 1990, it ran many, many unlogged hours on the
ground, while I developed and installed the ignition parts
configuration, the intake manifold and carburetor assembly, the
engine lubricating oil and oil cooler arrangements, the engine
antifreeze coolant and radiator assemblies (there were three
different assemblies, I had to redo the first one from scratch,
it did not cool enough, even on the ground) Also, after I had
built the propeller speed reduction unit and affixed it to the
engine, I tested several propellers, which I borrowed or rented
for the purpose of determining the best parameters for the   
propeller-engine combination, before I ordered a propeller made
to my specifications. Then there were the exhaust systems,
several of them. Yes, it was very much an error not to record
those many hours running on the ground."

Yvon Cournoyer 

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