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

Kobra wrote:

But I hope to learn more when the engine is
broken down and inspected. I will keep you all posted if you are
interested.

I am interested. Thanks for the story and my condolences.


--
Peter
























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Definitely warrants a separate post. With an 800 hour (SMOH) engine, this
news definitely has raised an eyebrow.

Any more stories of "early" overhauls that anyone care to share?

Marco Leon


"Kobra" wrote in message
...
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





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Saying the engine has 800 hours doesn't really say much. I'd be more
interested in how many years since overhaul. There are a lot of planes
for sale out there with low time engines that have sat for many years.
I would not feel comfortable flying behind an 800 hour engine if it has
sat for 10 years.

-Robert

Robert M. Gary wrote:

I would not feel comfortable flying behind an 800 hour engine if it has
sat for 10 years.

I'm a little nervous flying behind one that has sat for 6 months.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

Kobra wrote:

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.

Sounds like you have a pretty good A&P there.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

I'd love to know what caused the through bolt to shear or snap.
Thanks for posting.
Jim

"Kobra" wrote in message
...
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

There aren't a lot of possibilities, are there?

1. The case crack set up a vibration or torque that overstressed the
bolt -- and since it happened on startup when things are running less than
smooth in a Lyc, I'd bet on this one.

2. The bolt was WWAAAYYY overtorqued on installation. You'll never know
about this one. However, a through bolt shearing and a case crack by
another through bolt leads me to check the calibration on somebody's torque
wrench.

3. Something else in the engine was vibrating ... not likely as the whole
AIRplane would have been vibrating to shear a through bolt.

4. Defective bolt ... not likely as throughbolts get magnafluxed or x-rayed
at overhaul.

5. (Add yours here)


Oh, and BTW, mechanics cannot ground airplanes. IAs cannot ground
airplanes. The FAA (unless they pull the airworthiness cert.) cannot ground
airplanes. I know it is a common phrase, but the mechanic simply suggested
that it would be less than wise to fly the airplane in its current
condition.

Jim



"Jim Burns" wrote in message
...

I'd love to know what caused the through bolt to shear or snap.
Thanks for posting.
Jim

It could be undertorqued too. In that case there would be a lot of
fretting under the base flange of the cylinder, and probably on the
main bearing webs too.

If it hasn't been disassembled yet, you might check the other
throughstuds to see what torque is required to very slightly further
tighten them - giving you an indication of how close to the spec the
previous assembler was.

Another possibility is the hardness of the thru studs I don't know
what the spec is (probably not published ) but maybe Rockwell C = 48 to
52 or so?

That engine wouldn't have gone much further at all. You were lucky.

"nrp" wrote in message
oups.com...

It could be undertorqued too. In that case there would be a lot of
fretting under the base flange of the cylinder, and probably on the
main bearing webs too.

Yes, but that wouldn't have sheared the bolt at the jug stud ring as the OP
said it did. You would get fretting at that location, but I don't see a
failure mode in shear.


If it hasn't been disassembled yet, you might check the other
throughstuds to see what torque is required to very slightly further
tighten them - giving you an indication of how close to the spec the
previous assembler was.

And how much torque it takes to loosen a couple of them.

Jim