Those of you who look at the Real World Solutions web site and their latest photos may recall seeing a photo titled "Congratulations, it's a boy" which shows coolant squirting into the air from my overflow tank.  Photo taken at Charlie's fly in.  That was pretty good evidence of a coolant leak between combustion chamber and coolant galleys and supported by the fact that I had notice my coolant pressure increasing on the flight to Charlies by approx 11/2 psi per hour of flight. It started at a normal 10 psi and had increased to18 psi by the end of the flight. 

Well, by the time I had flown another two hours to Louisiana in and out of rain showers, etc, back-tracking, I finally made it to my destination.  There I found that the number 1 (front) rotor would shoot coolant out of the removed spark plug hole like old faithful when I pulled the prop through.  Clearly, had to fix the problem.    Upon opening up the engine I found two things

1.  One of the triangular pieces of the apex seal was missing - I first though it had fallen out on disassembly in my brother-in-law's garage,  but concerted search failed to locate it.

2.  There  were two "hot" spots (metal discolored to blue) on the front rotor side housings opposite each other.  One about the size of a half dollar coin was on the side of the missing piece of the apex seal. the second spot on the opposite housing at the same location was smaller about the size of a quarter.   It was clear looking at the "O" rings that the heat had compromised their integrity.  The appearance of the "O" rings at that spot was as if they had shrunk in diameter.  Elsewhere the "O" rings were slightly proud of the surface of the side housing indicating good sealing.

Someone on the list suggested that the missing piece of the apex seal might have gotten wedge at the end of the rotor and caused the problem.  At first, I was inclined to dismiss that hypothesis but failure to find any other explanation leads me to the following conclusion.

At this point, it appears that one of the triangular pieces of the apex seal (could not find it anywhere) left its proper position (undoubtedly during my assembly) and got lodged at the end (apex) of one of the rotors. May have been held their by some combination of the corner and side seal. In any case, it appears that one area of the rotor housing was slightly narrower than the rest (some area has to be {:>)). Every time that rotor with the wedged piece of apex seal passed that area it created tremendous friction and heated the side housing hot enough for the blue discoloration. The large Hot spot was on the side of the rotor that the piece of apex seal would normally have been. I think the smaller Hot spot on the opposite side housing was due to the rotor being pushed to that side by the wedged piece on the opposite side of the rotor. So the brunt of the heat occurred where the wedged piece was rubbing the side wall – but, at that same spot in rotation,  the seal piece forced the opposite side of the rotor into the opposite side wall creating a smaller hot spot – but still sufficient to overheat the "O" ring.

The wedged piece probably accounts for the initial tightness of the engine and after two hours of running it had either disintegrated or dropped out of the housing causing the engine to loosen up. Of course, by that time the damage to the "O" rings had been done and the results was the slowly increasing in my coolant pressure and of course the resulting "Congratulations, it’s a boy" photo.

The main point is that several folks (including Bruce T) expressed concern when I reported the initial tightness after reassemble from my apex seal failure on way to Sun & Fun.  However, I was in a hurry to get my aircraft off that derelict airfield and talked my self into the notion that I had just rebuild a really "tight" engine.  Clearly, I paid for that by having to open up and correct the situation.  This time there was no tightness and the compression was even better (guess the missing apex seal piece could account for less compression as well).

Fortunately, having friends like Laura and Tracy Crook really helps.  Laura was practically reading my mind in shipping the parts I needed to get the engine back together.  The longest time line was simply the time required to get the parts I needed.  No local source within 60 miles was found.

As always, I aim to share my experience in hopes it will preclude someone from making the same mistakes I made.

Between the brake failure/fire and the engine rebuild in no-rotary land during the heat and humidity of a Louisiana summer, its been one long month - but finally home and glad to be doing "Honey Dos"

Best Regards

Ed