oil blow out IO-360

Jim Burns wrote:
It seems like I'm agreeing with Jim these days, I'd also say that something
is creating excessive case pressure. Along those lines I just tore down a
horizontally opposed Kohler that was blowing oil from the breather faster
than I could dump it in. It had blown a cylinder barrel seal, not a gasket,
just an RTV seal. The key is that something caused the seal to blow. What
did I find? Cracked exhaust valve guide that allowed exhaust pressures into
the case.

Would that show up in a compression test though? I"m getting 79's all
around in the compression test. The IA seemed impressed with the
compression. Also, my EGTs seem to be running about the same.

-Robert

No, remember on a compression check your valves are closed, thus why I
suggested the valve wobble test. Not saying the guide is cracked, but it or
they could be worn. I was just trying to keep the symptom (excess oil out
the breather) separated from the cause (unknown) and relate what I had
discovered.

Let us know what you find.
Jim

"Robert M. Gary" wrote in message
oups.com...

Jim Burns wrote:
It seems like I'm agreeing with Jim these days, I'd also say that
something
is creating excessive case pressure. Along those lines I just tore down
a
horizontally opposed Kohler that was blowing oil from the breather
faster
than I could dump it in. It had blown a cylinder barrel seal, not a
gasket,
just an RTV seal. The key is that something caused the seal to blow.
What
did I find? Cracked exhaust valve guide that allowed exhaust pressures
into
the case.

Would that show up in a compression test though? I"m getting 79's all
around in the compression test. The IA seemed impressed with the
compression. Also, my EGTs seem to be running about the same.

-Robert

Jim Burns wrote:
No, remember on a compression check your valves are closed, thus why I
suggested the valve wobble test. Not saying the guide is cracked, but it or
they could be worn. I was just trying to keep the symptom (excess oil out
the breather) separated from the cause (unknown) and relate what I had
discovered.

If it were caused by a valve problem though would the oil still come
out the breather? My engine seems extreamly clean of oil. I can see oil
dripping from the breather.

-Robert

The breather exhausts excess pressure built up in your crank case. Anything
that would allow pressure created in the combustion chambers into your crank
case can lead to additional pressure and excess oil being emitted from your
breather along with the gasses. A bad oil ring on a piston or anything not
sealing in the valve train... valve not seating properly or a worn valve
guide.

I'm not an A&P, and this would be better confirmed by Jim or others, but I
would imagine that either a oil return line or even a pushrod sleeve would
allow pressure from a cylinder head into the case. Guys?

Jim

"Robert M. Gary" wrote in message
ups.com...

Jim Burns wrote:
No, remember on a compression check your valves are closed, thus why I
suggested the valve wobble test. Not saying the guide is cracked, but
it or
they could be worn. I was just trying to keep the symptom (excess oil
out
the breather) separated from the cause (unknown) and relate what I had
discovered.

If it were caused by a valve problem though would the oil still come
out the breather? My engine seems extreamly clean of oil. I can see oil
dripping from the breather.

-Robert

Check the valve guides and seals, with the valve closed,
compression will be good. But when the valve opens, if the
guide is worn or the seal is bad, oil will be sucked from
the top end.


"Robert M. Gary" wrote in message
oups.com...
|
| Jim Burns wrote:
| It seems like I'm agreeing with Jim these days, I'd also
say that something
| is creating excessive case pressure. Along those lines
I just tore down a
| horizontally opposed Kohler that was blowing oil from
the breather faster
| than I could dump it in. It had blown a cylinder barrel
seal, not a gasket,
| just an RTV seal. The key is that something caused the
seal to blow. What
| did I find? Cracked exhaust valve guide that allowed
exhaust pressures into
| the case.
|
| Would that show up in a compression test though? I"m
getting 79's all
| around in the compression test. The IA seemed impressed
with the
| compression. Also, my EGTs seem to be running about the
same.
|
| -Robert
|