Subject: Rotor "Weight Code" Stamp
From: Rotary Engine
Date: 4/4/2007, 2:25 PM
To: AARotary Engine



   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 Paul,

    All 3 rotors are "C".  The "E - like" character may be Japanese or
may have some other meaning, but it isn't the weight.  In recent years,
all or nearly all rotors are "C" thanks to improved manufacturing
methods by Mazda.

Jim Mederer


Thanks Jim.

Paul Lamar

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