"A" and "B" in rotary, what does it mean?

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  1. Post
    #1

    "A" and "B" in rotary, what does it mean?

    "A" and "B" in rotary, what does it mean?
    well what does the "A'' and "B" in rotarty engines names mean?

    e.g. 12A and 13B

    also how many different sizes are there?

    i know of
    10A, 12A, 12B?, 13B, 20B, 26B?

  2. Post
    #2
    The a, b, etc refer to different eccentric shafts. In the case of the 13b, I think you'll find there was a 13a but Mazda found that another (b) eccentric shaft offered better performance etc. I believe its "similar" to different cams, but that's taking a bit of an artistic license...

    This thread http://www.badrotor.co.nz/phpBB2/vie...ight=eccentric probably does a better job of explaining it than i did...

  3. Post
    #3
    Originally posted by mycoolcar


    also how many different sizes are there?

    i know of
    10A, 12A, 12B?, 13B, 20B, 26B?
    It can be any size you want it to be. Some companies tried some really odd rotary engines but the wankel now sold by Mazda seems to be the only one worth caring about as many of the others were rather ridiculous. There is this cool little one which I think is out of a motor mower in a display cabinet at Canterbury uni, it looks about 40cc, cute little thing

  4. Post
    #4
    .

  5. Post
    #5
    Originally posted by Savant
    The a, b, etc refer to different eccentric shafts. In the case of the 13b, I think you'll find there was a 13a but Mazda found that another (b) eccentric shaft offered better performance etc. I believe its "similar" to different cams, but that's taking a bit of an artistic license...
    Close - the 13A was a higher displacement version of the 10A, it had a longer "stroke" (or "rotor throw"), a much bigger housing and didn't rev quite as high. It was used in the first-gen Mazda Cosmo 110S in the late 1960's, and was produced in very low numbers. I understand there's less than half a dozen still in existance world-wide.



    The "A" and "B" (and sometimes "G") is just a model code to distinguish the version of engine. When Mazda changed from the 12a non-REAPS engine circa. RX2 and developed the REAPS 12A for the first-gen RX-7 and Japanese domestic RX-5, they were considering calling it the "12B" because the engine was so different internally.

  6. Post
    #6
    yea theres quite a few but those currently used and worth the performance are 12a's, 13b's and your odd 20b... respect to rotarys, how they work and how much power they can produce... NA and turbs'd.
    Not too keen on ever bying one (except maybe a newer one - eg RX 8 ) cuz of the short life they have and many hassles that are associated with them.

  7. Post
    #7
    Originally posted by Weebl
    and many hassles that are associated with them.
    yeah- insurance!!

  8. Post
    #8
    Originally posted by Weebl
    yea theres quite a few but those currently used and worth the performance are 12a's, 13b's and your odd 20b... respect to rotarys, how they work and how much power they can produce... NA and turbs'd.
    Not too keen on ever bying one (except maybe a newer one - eg RX 8 ) cuz of the short life they have and many hassles that are associated with them.
    They don't have short life if you treat them propperly, warming up a rotary doesn't mean turning it on and then bumping the accelerator on and off for 30 seconds.

  9. Post
    #9
    Rotary engines are just as reliable as most piston engines. The problem occurs when rotary drivers seem to think the engine was developed for formula one, and try to obtain the same redline between every set of traffic lights up Queen Street. If you treat a rotary in the same manner you would treat a smallblock V6, you won't have any problems.

  10. Post
    #10
    Thats new info to me.... I've heard from ex rotory owners and friends (+ a teacher once) that they almost certainly die before they reach 80, 000kms...
    then they need to be rebuilded, junked, whatever....

  11. Post
    #11
    if ur 14 are you gonna blow all ur student loan on a car + mods when u get ur liecence?

  12. Post
    #12
    velocity : what the f**k are you on about? what does this have anything to do with rotarys? or anything?

    you piss me off

  13. Post
    #13
    Your ex rotarty owners and friends didn't treat or don't like rotary's much then. Rotary's are a lot more reliable than piston engines. I mean hell, compare the moving parts list for starters !!!!

  14. Post
    #14
    massive wrote:
    Your ex rotarty owners and friends didn't treat or don't like rotary's much then. Rotary's are a lot more reliable than piston engines. I mean hell, compare the moving parts list for starters !!!!
    I'm sorry but that's the equivalent of saying a 2 stroke is more reliable than a 4 stroke.. just isn't the case. Rotary's have less components yes, but the components it does have work a lot harder and in turn wear quicker.

    Not to say they don't have a decent lifespan. But they are literally the 2 stroke equivalent, and we all know people with 2 strokes spend 80% of time in the garage fixing/rebuilding 15% riding and 5% trying to get the correct oil/fuel mixture at the servo. ^.^

    I'm not dissing rotary or 2 strokes either. Two of my favourite cars are DMACS AE86 corolla with rotary conversion and Mad Mikes 26b Quad rotor RX-7.

    Kind regards,


    Mysterious gentleman.

  15. Post
    #15
    What the **** man. Only 11 years too late.

  16. Post
    #16
    holy thread necro batman

  17. Post
    #17
    mycoolcar..such a good username

  18. Post
    #18
    Hamburglar wrote:
    What the **** man. Only 11 years too late.
    I thought that he was teh OP and just forgot about this for 11 years when I read your comment

    I remember that guy from BGLan actually.

  19. Post
    #19
    I've owned an S6 RX7 and a S7 RX7... never again...

  20. Post
    #20
    toM > wrote:
    I've owned an S6 RX7 and a S7 RX7... never again...
    Stock or modified?

  21. Post
    #21
    Neongreen wrote:
    I thought that he was teh OP and just forgot about this for 11 years when I read your comment

    I remember that guy from BGLan actually.
    Upset alot of folks on the dirty iconzarena/getsome forums a while back, nice enough guy in RL.

  22. Post
    #22
    Used to own a 1984 Mazda Cosmo Sedan (13b)....remember doing a 5th to 3rd chop at 80 kmh..missed 3rd and went into 1st....instant redline and rear wheel lockup.

    That car had about 164,000 kms on it when I sold it, and died (or got trashed at about 188,000 according to carjam WOFs)

  23. Post
    #23
    Was it a GT, what color was it, and was it modified. The detail isn't up to your usual standard pal.

  24. Post
    #24
    JvJ wrote:
    Close - the 13A was a higher displacement version of the 10A, it had a longer "stroke" (or "rotor throw"), a much bigger housing and didn't rev quite as high. It was used in the first-gen Mazda Cosmo 110S in the late 1960's, and was produced in very low numbers. I understand there's less than half a dozen still in existance world-wide.



    The "A" and "B" (and sometimes "G") is just a model code to distinguish the version of engine. When Mazda changed from the 12a non-REAPS engine circa. RX2 and developed the REAPS 12A for the first-gen RX-7 and Japanese domestic RX-5, they were considering calling it the "12B" because the engine was so different internally.
    The 13a was the only front wheel drive rotary Mazda produced and was used in an old Luce.
    The 12b was the first rotary with a single distributor and was used in late model RX-2's and RX-3's. The earlier 12a had twin distributors.
    Despite being a 12b, the housings were still labeled with "12a", as it was just an improved version of the engine.
    Last edited by Shinoya; 20th February 2019 at 1:21 am. Reason: -

  25. Post
    #25
    children born when this thread was started can get their learners permit now.