The eccentric shaft jets are used to squirt cooling oil into the interior
of the spinning rotors. The spent cooling oil and foam, falls back into the sump
through the center iron.
In cases where the engine is apart, some folks remove the spring and ball
from below each jet and replace them with a Weber carb main jet 200 size. This
removes the possibility that a piece of spring could eventually break off and
find its way to the oil pump.
In normal operation, the spring and ball close off the oil flow to the jet
when the engine is at idle. This is because the rotors need no cooling at idle
speed, and the oil pump is a bit on the small side displacement wise, so the
idiot light will blink constantly (indicating low oil pressure) at hot idle.
When the RPM increase, Oil pressure goes way up and the
centrifugal force lifts the balls off the seat and oil begins to spray
into the rotors.
I my opinion there is no need to add a Weber jet to the mix unless you have
jacked up the oil pressure either by increasing the relief valve cracking
pressure and,or add an aftermarket pump to run much higher than stock oil
pressure. I use and external pump, big bearing clearances and 100 PSI oil
pressure. I use 180 size Weber jets to limit
oil spray into the rotors. Note here that this is older engine data. The FD
93-95 twin turbo uses 115 PSI oil pressure, and I have no data on what the stock
jet size is for that pressure. So when I say "Limit" oil spray, that means with
Near FD oil pressures.
You can run the apex seals for quite a long time with no planned
lubrication. The oil scrapers are not perfect, so some oil will get by the side
seals and into the combustion chamber to lubricate the apex seals.
Older engines with poor oil scrapers get by just fine with the cheap
plastic oil metering pump lines broken off and making a mess on the side of the
block.
Crank case oils are designed to remain stable (not break down and not burn)
at high temperatures. This is a great feature in the sump. It is not a great
feature in the combustion chamber. We see here the same problem we see in small
2 cycle engines. Carbon build up. If you find you have run out of the expensive
little bottle of 2 cycle oil for your weed whacker, you might just pour in some
10W30 Valvoline, and it will work fine and make lots of carbon and sludge but
the engine will run, and you will get you weeds whacked. But you know better.
The 2 cycle stuff burns pretty clean and it burns ash free, so it lubricates and
then burns up and leaves in the exhaust stream.
For years the rotary was not supposed to use synthetic crank case oils,
because they do not burn well at all, and stay behind in the form of carbon and
sludge, that can quickly stick a corner seal or apex seal, in the bottom of a
groove and leave you with a low compression, no start some cool morning.
So here is why the Richard Sohn's metering pump adaptor is so neat.
You can run a 40 or 50 straight weight synthetic racing oil in the sump for
great oil cooling and the very highest film strengths and high anti foaming
content. And have 2 cycle oil lubricating the apex seals without making a big
mess of things. The very best 2 cycle oil is Redline synthetic, but far less
expensive oils work pretty good as well.
So if you were to land some day and find that the little 2 cycle oil bottle
on the fire wall is empty, just fill it up and go about your business. It is
very unlikely to have caused damage.
Premixing is a big pain, but is the very best way to lubricate the apex
seals. The OMP adaptor is second best and, pain free.
Lynn E. Hanover
In a message dated 9/24/2011 5:44:47 P.M. Paraguay Standard Time,
thomasmann51@gmail.com writes:
I know
that many use 2-cycle oil mixed in with the fuel for their your rotary
engine.
If you run it that way, is there any need to have the Eccentric
Shaft Oil Jets or could they be plugged?