|
Ed,
I must say, from what Lynn and others say, these
ceramic seals last forever, especially under our conditions.
I guess it boils down to what you can afford, they
would certainly cause less wear on the housing as well.
I will have to look at that down the
track!
George ( down under)
Sorry, George, I was mistaken, the seals are only
$300 each or $1800 for a set - only 1/2 the price I first mentioned
{:>)
Ed
Quote from Mazdatrix on Ceramic
seals
Note!!: These cost about $300 EACH ! -- that means
about $1800 (yes!) for 6 seals to do a 2-rotor engine.
----- Original Message -----
Sent: Wednesday, April 13, 2005 2:38
AM
Subject: [FlyRotary] Re: Rx-8 Rotors in
Rx-7 Block
It would seem to me that they are saying they
run the rotors backwards - that would put the recess in the rotor face
backwards.
The deeper side is to the side of rotation I'm
sure that would cause some power loss - then again I'm not the
expert!
The ceramic apex seals are the seals of choice,
I didn't know they were that expensive!
George (down under)
Appended below is an e mail from the owner of
MazdaTrix about using the Rx-8 rotor in an RX-7 block. Interesting
reading, now if only the ceramic seals were not $3600 for a set for two
rotors I'd be ready {:>). Makes for interesting
reading.
Here is an e-mail that Dave Lemon from Mazdatrix sent an RX-7 forum
member on the subject. Just thought you guys would find it
interesting:
We are using RX-8 rotors in one of our SCCA
E/Production "street port" 86-91 13B non-turbo engines.
We do no
mods to the rotors (except installing the racing rotor bearing).
We are
using RX-8 racing ceramic apex seals (the OEM RX-8 steel seals warped too
much having to cross the exhaust port).
(There IS enough metal to cut
the apex seal groove for either 86-91 2mm seals or earlier 3mm seals -- we
are looking into making that service available, but are not ready
yet)
The rotors are run "backwards" (front in rear, rear in front) so
the angle cut on the side of the rotor gives more intake opening timing
(RX-8 uses the cuts for the side exhaust ports).
Do not use the "oil
scraper ring" outside the second oil control ring.
DO NOT use RX-8
corner seals -- they DESTROY 86-91 side housings !!!! (use 86-91 corner
seals, TRUST ME).
They ARE lighter than
89-91 non-turbo rotors, have higher compression, and are less
expensive.
With all of the above said: We have YET
to attain even the SAME horsepower on the dyno as we are getting from our
race engine(s) using the 89-91 non-turbo rotors
!!!
Potentials:
With the RX-8 rotor having the side seal further
outboard, we were able to increase the (ported) intake opening timing
versus the earlier rotors -- it may be too much ??? (does not seem
likely)
Running the rotors with the angle cut for intake opening
may also be in the above category.
We always set pre-92 side seal
clearance at about .0015 (1 1/2 thou). The SMALLEST clearance we could
get, using the LONGEST of the available "pre-sized" RX-8 side seals was
about .010 (10 thou), with the worst on this set of rotors of about .016
(16 thou). This gives a much lower "sealing" than we like.
Other
than the above, at this time we are not at all sure why the power is less
than when using the earlier rotors.
No, we have not done the REAL
test -- run the SAME engine on the dyno, and only swap the rotors
(backwards, then normal). That equals three builds, and three full dyno
on-and-offs + dyno sessions.
Dave Lemon,
Owner of
Mazdatrix,
The dyno operator and driver of the E/P
car
|