Oil leak on top of the engine

Jay wrote, "I've bought a torque wrench, and I'm going to be checking ALL of
these bolts every time I change the oil, from now on."

Jay,

I'm sure you know this from your motorcycle Zen days, but I've learned (and
relearned a couple times) to be certain the click-type torque wrench setting
is correct before using it -- and to loosen it completely before putting it
away. (Maybe the latter is an old wives' tale.)

I've also learned to be careful to note whether foot-pounds or inch-pounds
is specified. It seems that aircraft bolts are often torqued considerably
less than I would expect them to be.

Regards,

Jon (not an A&P or even a motorcycle mechanic)

PS: I shall now be checking my engine's bolts. Thanks for the heads up!

I'm sure you know this from your motorcycle Zen days

*sigh* Some days I wish I'd stuck to motorcycles...

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

In article 6q3Pd.63958$eT5.59714@attbi_s51,
"Jay Honeck" wrote:

The point I'm trying to make is it appears that some bolts being torqued
have been overlooked and what is the chance that the cylinder nuts & thru
bolts had been overlooked also?

Simply, You don't know until you check. It'll require 10 minutes if you
have easy access to the engine.

I'm having my shop check these this morning.

To those who think that the bolt might have been loose from the start,
remember: I watched the shop build this engine, and I personally saw them
check the torque on the engine case bolts. They *were* tightened to spec.

I also know that they never re-checked them, however, and my main mechanic
has admitted that they never check these as a matter of course.

In the case of the O-540, anyway, the case bolts are torqued surprisingly
low, and they are not secured in any way. No cotter pin, no safety wire, no
LocTite, no lock washer -- NOTHING prevents those nuts/bolts from loosening
over time. It seems like a ridiculous over-sight, but that's the way it
is.

A guy on the Cherokee Chat actually had a case bolt FALL OUT after loosening
over time from vibration, so this is not an unheard-of problem. I'm
surprised it's never been addressed in this forum before -- at least not in
my 7 years here.

I've bought a torque wrench, and I'm going to be checking ALL of these bolts
every time I change the oil, from now on.


Another caveat on torquing (from an old AI): All torquing should be done
"wet", with a drop of oil to lube the nut, so as not to get a false
torque reading.

On Fri, 11 Feb 2005 18:27:23 GMT, Orval Fairbairn
wrote:

In article 6q3Pd.63958$eT5.59714@attbi_s51,
"Jay Honeck" wrote:

The point I'm trying to make is it appears that some bolts being torqued
have been overlooked and what is the chance that the cylinder nuts & thru
bolts had been overlooked also?

Simply, You don't know until you check. It'll require 10 minutes if you
have easy access to the engine.

I'm having my shop check these this morning.

To those who think that the bolt might have been loose from the start,
remember: I watched the shop build this engine, and I personally saw them
check the torque on the engine case bolts. They *were* tightened to spec.

I also know that they never re-checked them, however, and my main mechanic
has admitted that they never check these as a matter of course.

In the case of the O-540, anyway, the case bolts are torqued surprisingly
low, and they are not secured in any way. No cotter pin, no safety wire, no
LocTite, no lock washer -- NOTHING prevents those nuts/bolts from loosening
over time. It seems like a ridiculous over-sight, but that's the way it
is.

A guy on the Cherokee Chat actually had a case bolt FALL OUT after loosening
over time from vibration, so this is not an unheard-of problem. I'm
surprised it's never been addressed in this forum before -- at least not in
my 7 years here.

I've bought a torque wrench, and I'm going to be checking ALL of these bolts
every time I change the oil, from now on.


Another caveat on torquing (from an old AI): All torquing should be done
"wet", with a drop of oil to lube the nut, so as not to get a false
torque reading.

Let's hope the old AI isn't doing much any longer. Whether a bolt is
wet or dry (oil, locktite,graphite) will change the torque specs. The
manufacturer should specify the condition of the bolt for those who
have their JD's.

On Fri, 11 Feb 2005 14:36:50 GMT, "Jay Honeck"
wrote:

The point I'm trying to make is it appears that some bolts being torqued
have been overlooked and what is the chance that the cylinder nuts & thru
bolts had been overlooked also?

Simply, You don't know until you check. It'll require 10 minutes if you
have easy access to the engine.

I'm having my shop check these this morning.

Good for you.

To those who think that the bolt might have been loose from the start,
remember: I watched the shop build this engine, and I personally saw them
check the torque on the engine case bolts. They *were* tightened to spec.

New bolts, new nuts, new lock washers, torque wrench calibrated
recently?

I also know that they never re-checked them, however, and my main mechanic
has admitted that they never check these as a matter of course.

Tsk, tsk! What else do they not do?

In the case of the O-540, anyway, the case bolts are torqued surprisingly
low, and they are not secured in any way. No cotter pin, no safety wire, no
LocTite, no lock washer -- NOTHING prevents those nuts/bolts from loosening
over time. It seems like a ridiculous over-sight, but that's the way it
is.

If all of the engines would have failed, they would have changed the
procedure. Something else is wrong.

A guy on the Cherokee Chat actually had a case bolt FALL OUT after loosening
over time from vibration, so this is not an unheard-of problem. I'm
surprised it's never been addressed in this forum before -- at least not in
my 7 years here.

I've bought a torque wrench, and I'm going to be checking ALL of these bolts
every time I change the oil, from now on.

Have it calibrated, and remember that each time you torque it, the
bolt stretches. Some years ago, when it was credible, AVWEB had an
article on torque. You can probably still pull it up.

"Jon A." wrote, "Some years ago, when it was credible, AVWEB had an article
on torque."

Jon,

Do you feel that AvWeb is no longer credible?

Jon