Well Perry got as far as Palm springs and the engine overheated.
He called and I drove out there to help. We at first thought
it was the classic old o-ring problem. Then we took the cowl off
and it looked like a water pump as coolant was coming out of the weep hole.
So we got a new water pump and put that on there. Then Perry took off 
this morning and it overheated again. 

Since we thought we still had a leak we did the Barsleak trick.
The engine did some real strange things like the temp went way high
with the water pressure real low.
 
So then Perry thought it might be the thermostat. 
When Perry too it out it seemed to be stick closed. So we went 
to a hardware store and got a 1/2 inch NPT galvanized pipe plug
for the water pump  return passage. Perry had quite some time ago 
tapped it for the pipe plug as he used to run the engine without 
the thermostat. We started it up and things almost looked normal.
the pressure looked normal and it started creeping up towards temp
redline we we ran it at 3000 RPM for several minutes. It is still
easy to start which is a good sign.

By that time it was hotter than Hades and Perry felt it would
be better to take off tomorrow morning for a another test flight.
Se we drove the 100 miles back to my place. On the way I thought
we should have bought a cooling system pressure checker so we 
could test the cooling system when it was cold for o-ring leaks.

We will do that today and take a engine hoist with  up early tomorrow
morning in case we have to pull the engine and brink it back to LA
for overhaul.

Lessons learned. 

A. Make sure you can get your water pump off and on with
out removing a bunch of other parts like the entire engine.

B. Do not use the water pump for engine mounting brackets!!!!

C. Do not use a thermostat!!!!! Why risk a $3000 engine on a $10 thermostat.
You can look at a cowl flap and see whether it is open or closed.
I defy anyone to do that when the thermostat is in the engine.
I am going to be as adamant about this in the future as I am about
silly plugs up engines. Build a butterfly valve and put it
in the cooling air intake if necessary.

D. Buy a coolant system pressure tester and keep it in the airplane.

E. Install a coolant drain outside the cowling at the lowest point in
the system so you can drain the engine and system completely.
The use of modern Barsleak requires that you get all the antifreeze
out of the engine before you put it in. Very important point as it can
take hours removing and installing the cowling.

F. Always use teflon encapsulated silicon O-rings when overhauling
your engine. Something as simple as a water pump failure in the air can ruin
your engine. You need as much going for you in a case like that as
possible. This gave me renewed incentive to look into bellville springs
or smaller diameter tension bolts.

We still are not sure what happened or if we have it fixed. It could
be the coolant O-rings after all. In any event Perry will use teflon
encapsulated coolant O-rings in the future. I plan to test the 
old water pump seal for leaks when I get time.
 
Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

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