Oil leak

I have a 1966 Cherokee 180 with fixed pitch prop. I have noticed some
oil streaks on the back plate of the prop spinner, apparently seeping
out between the prop and flywheel. Anyone have an expereince with this?
Is there a plug in the front the hollow (I assume) crankshaft that
could be leaking? Is this a common problem? Thanks for any info.
--
Gene Seibel
Gene & Sue's Aeroplanes - http://pad39a.com/gene/planes.html
Because I fly, I envy no one.

Gene,

This is usually an indication that the front main seal of the engine is
leaking. This is the seal at the point where the crankshaft comes out
of the crankcase.

It is not as bad as it sounds, as long as you get it fixed promptly.
If you leave it, it will often get worse quickly. Then you will think
it is raining (droplets on the windscreen). Shortly after that...
well... how are your off-field landing skills?

Gene Hudson
CFII, ASC

On 2 Jan 2005 16:29:32 -0800, "Gene Seibel" wrote:

I have a 1966 Cherokee 180 with fixed pitch prop. I have noticed some
oil streaks on the back plate of the prop spinner, apparently seeping
out between the prop and flywheel. Anyone have an expereince with this?
Is there a plug in the front the hollow (I assume) crankshaft that
could be leaking? Is this a common problem? Thanks for any info.

As another poster indicated, it may be the forward crankcase seal
leaking.

If you have a hollow crank, there is indeed a plug smacked into the
forward end of it. Depending on your spinner installation, removing
the spinner may or may not make this plug (and the oil leak) visible.

If you have a solid crank, the inside of the crankshaft will be
visible as a machined recess that should have some turning marks
visible on the face.

If you have a "plug" it is a slighty cupped steel disc, placed into
the crank with the cupped side outward, and smacked with a drift to
flatten it out and drive the edges outward into the sides of the
recess in the crank.

Not sure anymore what Lycoming says to seal them with, we useta use
hard-setting Permatex. If they leak, you smack them in the center with
a bluntly pointed punch, turning the disc inside-out, and lever it out
with the punch. Clean up the recessed area, and poke in a new one.

TC

I had a main leak once before on another plane, and the oil remained
behind the flywheel. I believe this is different and probably a plug as
you describe. There is a plate under the prop bolts, so removing the
spinner will not make it visible. Time for professional help. Thanks
for the info.
--
Gene Seibel
Gene & Sue's Aeroplanes - http://pad39a.com/gene/planes.html
Because I fly, I envy no one.

If you have an O-360-A3A, it does have a hollow crank with the RPM restriction
on the tach and a plug in the front. The -A4A is a solid crank.


--
Dr. Nuketopia
Sorry, no e-Mail.
Spam forgeries have resulted in thousands of faked bounces to my address.

wrote:
: If you have a hollow crank, there is indeed a plug smacked into the
: forward end of it. Depending on your spinner installation, removing
: the spinner may or may not make this plug (and the oil leak) visible.

Keep in mind that there's an AD against this engine with the hollow crank. It
involves removing that plug and inspecting for crankshaft corrosion on the inside. I
don't remember how often it needs to be done, but if it was replaced recently that
could be the cause of the "new" leak.

-Cory


--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

I had a couple of seals go bad over 11 years in my Cherokee 140. Both
times the seal itself was blown completely out of its land (there was NO
sealing action). Both times we noticed a residue on the inside of the
flywheel pulley and a few fine drops on the windshield. I once flew it
for 2+ hours in that condition and did not lose a measurable amount of oil.

However, I once saw a Warrior that had blown a seal and it was down 3
quarts after a 1 hour instruction flight. Upon shutdown, there was a
stream of oil running out of the flywheel and a puddle on the ground.

The fix involves removing the prop and stretching a new seal over the
crankshaft flange, then glueing it into place.

Good Luck,
Mike

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On 2 Jan 2005 16:29:32 -0800, "Gene Seibel" wrote:

I have a 1966 Cherokee 180 with fixed pitch prop. I have noticed some
oil streaks on the back plate of the prop spinner, apparently seeping
out between the prop and flywheel. Anyone have an expereince with this?
Is there a plug in the front the hollow (I assume) crankshaft that
could be leaking? Is this a common problem? Thanks for any info.

There is a seal at the front of the engine where the crankshaft exits.
It's glued in place and the glue can come loose.

Replacing it takes a few hours, as the prop needs to be removed and
replaced, but shouldn't be a big deal for an experienced technician (if
that's what's causing the leak).


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

wrote:

Keep in mind that there's an AD against this engine with the hollow crank.

AD 98-2-8.

It
involves removing that plug and inspecting for crankshaft corrosion on the inside. I
don't remember how often it needs to be done, ....

The first inspection must be done within 10 years of the original ship date,
1,000 hours from date of the last overhaul, or six months from issuance of the
AD. After that, every five years. Urethabond can also be applied during the
inspection. If this is done, the crank never has to be inspected for this AD
again.

... but if it was replaced recently that
could be the cause of the "new" leak.

Sure could.

George Patterson
The desire for safety stands against every great and noble enterprise.

G.R. Patterson III wrote:

Urethabond can also be applied during the
inspection. If this is done, the crank never has to be inspected for
this AD
again.


Last that I had heard (admittedly it has been years since I checked in
detail) the urethabond could only be applied if the crank was removed
from the engine. CPA was lobbying to allow the procedure to be
perofrmed with the crank still installed. What is the current status of
this?

Bruce Cunningham
N30464 C177A