Toasted my engine

Flyers,

This was part of a post in "Selling my Garmin 296" and decided to make it a
separate post. Sorry for the redundancy.


Kobra wrote:
...I toasted my engine about 3 weeks ago.


Urgh. Sorry to hear that. What happened?

I have a Cardinal RG with a IO-360A1B6 with 1000 hours on it. On one short
30 min. flight to Cape May, NJ (WWD) I noticed a small amount of oil running
down the nose gear door. I did a cursory look and found the oil level
unchanged and saw nothing through the oil access door. I wiped it off.

On the flight back all oil indicators were fine. When I landed the drip of
oil was back. No big oil loss, but when you fly the same airplane you know
what's suppose to be there and what's not. I called my mechanic and
co-owner and explained the problem. At first the mechanic was not
concerned.

My partner flew a few days later on a short flight and when he landed the
A&P came over to say hello. He then noticed the oil on the gear door. He
grounded the plane and the next day called me to the airport. He showed me
a pretty good leak coming through something called a "though-bolt" on the
number two cylinder. A though-bolt is a long bolt that goes completely
through the engine from one cylinder to the other and helps keep the case
enlighten and tight.

That wasn't the big problem though, he said I could fly with a minor leak at
the through-bolt to TBO. Next he did a dye penetrate test and found a crack
in the case in front of the number 4 jug at one of the studs for that
cylinder. That did it. The engine had to come off, the case split and a
new case was ordered.

The story goes on though. As he was taking the engine off he found one
other interesting item. One of the through-bolt nuts on the bottom of
cylinder number 3 was sheared off completely flush the cylinder base.
That's when the hair on the back of my neck stood up. I have to think that
all this was related as the nut was still laying in the bottom of the
engine. This was recent!

Next I had a recollection of starting the engine before my flight to WWD and
I remember that I heard a "snap!" just as the engine caught. It was loud
enough to make me say, "...what the %$#@ was that?!" and just soft enough
for me to dismiss it and ponder, "...did you really hear what you think you
heard?"

The rest is speculation, but maybe that was the nut snapping off and
something bad happened in the engine causing the leak at the through bolt on
number two cylinder. Maybe the engine was ready to self-destruct in the air
on the next flight. Who knows? But I hope to learn more when the engine is
broken down and inspected. I will keep you all posted if you are
interested.

Kobra