>>
>> > Hi Paul,
>> > I'm enjoying following along with your current threads!!
>> > Hope you don't mind me chiming in here again to ask another
>> newbie
>> > question:
>> >
>> > I've been slowly acquiring S5 NT (9.7 : 1) rotors for my
20B NA
>> project
>> > (much cheaper that RX8 rotors). I had 2, and just
received the
>> 3rd one
>> > today. I've been trying to be careful to make sure I get
>> rotors with
>> > matching weight code stamps, but the one I got today is
>> different. Can
>> > you help here? I hope you don't mind me including
pictures!! I
>> tried
>> > to make the files small. The first 2 pics are the rotors I
>> already had,
>> > and they show a "C" along side another weird symbol
(kinda looks
>> like
>> > a 7).
>> >
>> > The next pic is the rotor I got today. It shows a "C" along
>> side an
>> > "E" :
>> > My question is.......Is it OK to use all these rotors
>> together? Are
>> > these all S5 (9.7 : 1) rotors? Is this last rotor a
weight code
>> "C" or
>> > "E" ? What's the other symbol of Letter mean?
>> >
>> > Thanks again for all your help and knowledge!!
>> > Don
>> >
>> > From what I gather you can't mix and match weight codes.
>> > I think you need to have it balanced by an experienced
>> > rotary engine balancer. The rotors must be balanced
>> > about their center point and matched with all the other
rotors
>> > for weight and then the counter weights adjusted
>> > for the exact weight of the rotors. There is a guy here in
>> > So Cal that does it.
>> >
>> > Rotor weight codes.
>> > The only thing I can find is this.
>> >
http://www.rx7club.com/showthread.php?p=1309602#post1309602-
>> >
>> > I'll forward this to Jim Mederer. Hopefully he will have time
>> > to help as he gets the really hard questions :)
>> >
>> > Paul Lamar ...No rotor no motor.
>>
>>
>> Hi Don;
>>
>> These all appear to "C" weight rotors. For a 2-rotor, letter
>> codes must
>> be adjacent,
>> e.g. B/C, D/E, C/D are OK (A/C, B/D are NOT)
>> The rotors themselves are balanced about their centers at the
>> factory.
>> I am not sure what the balance requirements are for a 3-rotor.
>> I believe the backwards "E" and other characters are Japanese -
>> don't
>> know what they mean.
>> Theoretically, the S5 rotors weigh the same as the 20B rotors,
>> and you
>> "should"?
>> be able to use the 20B front and rear counterweight without
>> rebalancing.
>>
>> I posted some rotor/balance info a few weeks ago.
>> The S5 rotor faces are machined, the S4 have a rough cast
>> appearance.
>> You could also measure the depth of the combustion area.
>> See attached file
>> -> might be worth adding to the website. I don't have any
turbo
>> stuff.
>> A couple of housing comparisons might be useful as well,
I'll see
>> what I
>> can scare up...
>>
>> When mixing and matching parts for higher than stock rpm, a
custom
>> balance is not a bad idea.
>>
>> Cheers
>> Cary
>>
>>
>> Thanks Cary,
>> This is what I have:
>>
>> All are machined faces.
>> Thanks,
>> Don
> Hi Don;
> The S5 NA rotors are at a bit of a premium for racing and higher
> activities :)
> Worth a quick depth check on the rotor recesses to ensure they
are all
> the same.
> Personally, I would run the stock 9.0? 20b rotors in NA mode for the
> 5-8% HP loss.
> If you have the room under the cowl - you could re-add a turbo later.
> Just curious, what is your project?
> (Sorry if I've missed it, I don't read all the emails)
>
> Cheers
> Cary
Hi Don;
Also meant to ask if you have removed and replaced the stock 20B exhaust
sleeve inserts.
I have heard they are quite restrictive and many people replace them
with 13b turbo inserts.
Although removing them is a good way to break taps...
Cheers
Cary
Don,
I removed the stock 20B exhaust inserts from my engine. Not a job for
the faint of heart! The best way I found was to grind away the material
from inside the port until you can see the roll pin, then drive them
through with a punch. It ruins the inserts, but I didn't have any
future use for them anyway.
Mark S.
If your off next Sunday Don, Allen and anybody else in the
neighborhood and you don't mind driving to Lockhart I will be there
10:00 or 11:00 AM visiting Mark. We can have a mini Rotary Engine in
Aircraft Meeting and How to cool Your Wankel book signing at Mark's
hangar.
Paul Lamar
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