Thank you. That was more in-depth than I could have conveyed trying to
restate what Veeduber had told me.

Cy Galley wrote:

In the automotive engine the same gear on the cam drives the distributor and
the oil pump. It is so designed that the oil pump is driven by a tang off
the distributor shaft but the gear is on the distributor end. Removing the
distributor, removes the gear drive and also disconnects the oil pump drive.
The oil pump can then be driven by a shaft independently of the cam.
On the other hand the mag is driven by a gear train off the cam and the oil
pump is driven by its own dedicated gear. Removing the mag does not remove
or disconnect the oil pump drive so that it can be driven by a mechanical
source outside the engine.
The configuration for driving the oil pump is completely different. Yes, I
have lost the oil pump drive in an automotive setup and still had proper
ignition. If you lose the distributor drive, then you would also lose your
oil pump. Since the aircraft engine is designed differently with a
different drive of the oil pump, this cannot happen.
You can lose the ignition and still have oil pressure.
But you cannot prime the oil system in an aircraft engine via the mag drive
unless you turn the entire engine. Much easier to turn the prop or starter.
In a word NO!

"Bruce A. Frank" wrote in message
...
Cy,

We are all here to learn...well some of us are. Do you know have the
energy to elaborate as to why? Or do you just enjoy being abrupt?

I do know the answer now because Veeduber went to the trouble to
privately email me and explain the differences between the engine
designs. You had a chance to enlighten others here on RAH. I am sure
there would have been one or two who would have appreciated a more
complete answer.

Cy Galley wrote:

In a word NO!
"Bruce A. Frank" wrote in message
...
The method that I have used on automotive engines is to take an old
distributor shaft with no cam gear on it. Remove the distributor from
the engine block, chuck the old shaft in a 1/2 drill, stick it down
the
shaft hole until it engages the oil pump and spin away. I have been
able
to develop full oil pressure on new engines that way. Would a similar
concept work on a magneto shaft hole?

Dave Hyde wrote:

David O wrote:

Lycoming's service instruction 1241c (still active) addresses the
subject of pre-oiling after overhaul,

Thanks to all - I have the service instruction, I was looking for
other ideas on pressurizing the system. Bought a sprayer today,
if it works I'll use it, if not I'll just cold-crank the engine.

Acro/tailwheel refresher starts tomorrow.

Dave 'one-armed paperhanger' Hyde


--
Bruce A. Frank