> > Fred Vandeman wrote:
> > >
> > > As many/most of you with aircraft instillations......I
will
> > be supplying
> > > oil to the apex seals by putting 2cycle into the fuel.
> > I'm finishing
> > > my 20B overhaul and will be closing the front cover
> > tomorrow. Should
> > > I remove the drive gear and shaft........or leave it in?
> > If it were me I would take it out. No telling what it would
> > do with no load.
> >
> > Paul Lamar
> The roll pin (red arrow in pix) squirts oil onto the oil pump
chain. I
> was not sure if it would get enough lube without it so I left
mine in. I
> took the gear off though, so the shaft no longer rotates. If
you remove
> the shaft, oil will just run out the end of the bore.
>
> Chuck Dunlap
Good point Chuck. Sorry I missed that.
Paul Lamar
I removed the gear/shaft asembly and threaded the shaft (inside
and out) for pipe plugs. Therefore, the shaft is pressurized and the
oil pump chain is still lubed thru the roll pin hole.
Ken Powell
I'm replying via a web browser... So if this gets tacked onto the front of the
message instead of the end, my apologies.
I just pulled the gear and shaft for my oil injection pump, and threaded the
hole of the front cover oil supply gallery to take a 6mm setscrew. Seated in
the oil gallery just fine, and used a little lock-tite to keep it there.
Now the front cover of my 20B looks just like that of a 13B, and there's no
roll pin in it anywhere... just a hole. Looked to me like that's where the oil
came out of the metering pump shaft after doing it's job. Guess I'll have to
go back and look again. At least the plug is reversable!
Tom Kendall
I am not so sure that lubes the chain. It might have that effect but
I think the hole is mainly for the roll pin which I assume keeps the
shaft in place. If it were not for that roll pin the metering pump
gear could become disengaged from its drive gear upon assemble. I
think there is plenty of oil coming out of the front main bearing
and splashing around in there to lube the chain.
Come to think of it I am sure of it as just to the right of
that roll pin is the vent for the oil reservoir for the injection
pump. That is vented to the near atmospheric pressure in the
front cover. Therefor no pressure ... no squirt. We went around
and around about this quite some time ago.
Old message below.
Paul Lamar
***********************************************************************
From: Paul <rotaryeng@earthlink.net>
11/15/2000 22:36
Subject: oil injection pump
Somebody mentioned they thought the oil injection pump was not a pump at all
but just a metering device that relied on engine oil pressure.
Not the case. The oil injection pump is indeed a pump and is gravity fed with oil at
atmospheric pressure. The pumping action comes from the fact that the plunger
moves up and down in its bore as shown in this drawing from the Mazda book
called "Rotary Engine". The stroke of this up and down motion hence the amount of
oil injected is controlled by the throttle opening linkage.
The mechanical pump is an off the shelf motor cycle part bought out by Mazda.
As I recall it is made by Mikuni.
Paul Lamar
Guys.
I took the cover back off and the my 20B also does not have a roll pin in the hole......just the
hole. When I line up the cover and measure the position of the hole/roll pin .....it does line up
with the oil pump drive chain. Not that, that answers the question. I did reinstall the metering
pump drive shaft (leaving the gear off) and secured the metering pump end of the shaft with RTV
and put a flat plate over the pump attachment area using the pump attach bolt holes. This will
allow oil to flow out the hole/roll pin as normal, even if it truly isn't needed.
Another point.....how does the e-shaft gear that turns the oil metering pump and the distributor
shaft get its oil.......splash or oil pushing out of the inner journal of the oil metering pump
drive shaft....onto the gears and lubricating all three gears??? Am I over thinking the problem?
Fred
I assume it is splash as that whole inside front cover is awash in oil.
Here are pictures of the inside of my 12A and Chucks.
You can clearly see the vent hole above the shaft in the 12A.
All of this is very costly in terms of drilling all these oil
galleries so I would not be a bit surprised if Mazda was not
simplifying and cutting cost from year to year.
Paul Lamar
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