The inner O-ring slot width is .145 wide and .065 deep.
A little deeper than before. The old slots were .063 deep.

Outer O-ring slot is .115 wide and .065 deep.
Again a little  deeper I think. this is good news
as it give more room for the .093 O-rings.
The same .093" section diameter O-ring we are using
now should work fine.

I think the outer slot is a bit deeper than the 2nd gen
.065 but I think an .080" O-ring section diameter will work fine.
The width is a bit restrictive for a .093" diameter IMHO.

Of course all four O-ring slots are now in the rotor housing and not
in the end housings.

I saw some things I had not seen on 2nd gen rotor
housings. Mazda mills out some of the wall around the leading
spark plug as can be seen in these pictures. They may have done
that in the 3rd gen turbo engines. I am not sure why they do this.
Perhaps to cool the metal better in this area. This is the hottest
part of the rotor housing. Makes it more difficult to get a cylinder
head thermocouple down near the combustion chamber. It will  probably have
to drilled in at an angle.

There are also steam pocket groves near some of the
tension bolt bosses I had not noticed in the 2nd gen
housings. I did notice those on the sand cast p-port rotor
housings however.

Both rotor housing wear surfaces  were coated with this black soot.
It was real easy to wipe it off with acetone. Usually it is a lot
harder to get off as it is usually baked on. Once I got that
off the rotor housing surface was in excellent shape. I know nothing
about this low power engine other than it had been in a severe crash.
I may have to buy a new front housing as it was cracked in the
crash. The water pump shaft was jammed back into the front cover
but the damage was minimal.  A new water pump cartridge
will fix that.

The rotor housings will be bored tomorrow for the p-port ss tubes
which will be welded in.

Paul Lamar ...No rotor no motor.

Paul,  I have not spoken  about welding in the inserts but I think it
is not a good idea. As Lynn originally suggested,    I believe the
thin rotor housing liner must flex as the pressure of the rotor
passes by.    Welding in the insert will almost certainly inhibit
this.   Expect cracking and damaged seals as a result.     Jerry

I don't agree. The .065 thick hardened steel liner has a high modulus of
elasticity. It was added by Mazda to reduce rotor surface flex. Furthermore
it is backed up by a 1/4 inch of aluminum that is well and truly attached to the
steel liner. No way is that going to flex under the influence of
an apex seal spring.

I am putting my money where my mouth is. I am risking two perfectly
good RX8 rotor housings to prove it.

Old message:

Jeff Spitzer wrote:

" Don't forget that there are really
two springs here. One is the apex seal spring. The seal spring is really secondary
in importance to the trochoid surface "spring." The frequency of the spring mass
system when just the seal and leaf spring are considered is probably so low that
the seal would be off the housing for a major part of the cycle for resonance.
This just can't happen. That's why I made the point originally that compatibility
of seals and trochoid surfaces must account for all factors (seal mass, friction,
surface "spring rate" etc)."

Jeff Spitzer

Jeff worked for Paul Moller and his responsibility was redesigning the one
rotor air cooled OMC rotor engine to a two rotor liquid cooled engine. Jeff
now is the project engineer on the Predator UAV.

For the full conversation read the recently updated.

http://www.rotaryeng.net/history.html

Paul Lamar ...No rotor no motor.

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