oil blow out IO-360

Jim Macklin wrote:
The engine is old, nearly ten years, check all the seals and
mating surfaces. You only have 900 hours, but that is less
than 100 hours a year. Corrosion in the cylinders and blow
by, and oil being sucked past the ring into the combustion
chamber are all possible, Check valve guides and seals,
differential compression and if available, borescope it.
Higher oil pressure would increase the leakage, but not
effect the valve guides or rings. An oil separator will
only help if the oil is going out the breather tube.

The only place I'm seeing any oil is at the breather. I had a full
prop/gov overhaul last year and they replaced the front engine seal. I
wasn't having any problems with the prop, I had it overhauled because
oil was leaking from the gov. Now I think I've got a clean enough
engine that I can actually tell where the oil is leaknig from.

-Robert

You might see about plumbing in a pressure gauge to read the
crankcase pressure in flight, also, there should be a baffle
to keep the oil from directly splashing on the breather
pick-up.

It is possible that the work that was done reduced the
leaking from the crankcase [reduced venting] and it is now
increased at the breather. If there is too much blow by, a
top overhaul or perhaps just a bad cylinder needs honed and
new rings. But a sudden change in the oil usage pattern is
cause for more investigation. You see oil at the breather
because it is not burned, but is atomized particles and
vapor. But you can be burning oil because of bad rings or
valve guide leakage and that could be masked in the exhaust
stack. Check plug condition and the stacks should be chalky
gray, not black or brown greasy. Have someone do a full
power run-up and you look at the exhaust for color, oil
smoke
is bluish, excess fuel is black smoke. White smoke is a
cold engine and water condensation, or a water jacket leak
on a water cooled engine.

see
http://www.lycoming.textron.com/main...ons/index.html

--
James H. Macklin
ATP,CFI,A&P

"Robert M. Gary" wrote in message
ups.com...
|
| Jim Macklin wrote:
| The engine is old, nearly ten years, check all the seals
and
| mating surfaces. You only have 900 hours, but that is
less
| than 100 hours a year. Corrosion in the cylinders and
blow
| by, and oil being sucked past the ring into the
combustion
| chamber are all possible, Check valve guides and seals,
| differential compression and if available, borescope it.
| Higher oil pressure would increase the leakage, but not
| effect the valve guides or rings. An oil separator will
| only help if the oil is going out the breather tube.
|
| The only place I'm seeing any oil is at the breather. I
had a full
| prop/gov overhaul last year and they replaced the front
engine seal. I
| wasn't having any problems with the prop, I had it
overhauled because
| oil was leaking from the gov. Now I think I've got a clean
enough
| engine that I can actually tell where the oil is leaking
from.
|
| -Robert
|