anyone have a list of id numbers for counter weights
and info as to what they are for?
I have a 1029a rear counter weight and i would like
to know what it is for.

matt

 

j9fd3s should know. He knew a 1757 was a front counterweight for a '74-'78 13B. Or maybe that's the number for everything in the rotating assembly? He'll know.

 

1757 is everything on a 74-75 13b, ie rotor housings are 1757-10-100, etc

heres an incomplete list
0810 67 cosmo 10a
0820 68 r100

2090 70-73 12a
1757 is 74-75 13b
1881 is 74-75 12a
8871 is 79 -80 12a
n201 is 81-82 12a
n231 is 83 12a
n236 is 12at
n249 is 84-85 12a
n304 is 84-85 13b
n326 is 86-88 na
n332 is usa 86-88 turbo
n318 is 86-87 turbo jdm
n319 is 88? jdm
n340 is wierd 88.5 hybrid jdm
n350 is 89-91 na
n370 is 89-91 t2
n390 is 13b cosmo
nf01 is 20b
n3a1 is fd
n3h1 is rx8




1029a doesnt do anything for me

 

Good ol' NF01. I've seen it here and there.

 

I guess my question should have been is there any
identifying numbers stamped on the rear counter weights
to tell what they are from?
I know there are no numbers stamped on the front
ones but looking at a few of the rear ones i have they all
have numbers stamped on them but i am starting to
think they don't really mean anything.

matt

 

I've seen 1757 on my FRONT counterweight. I don't know if 12A weights have numbers on them.

 

FYI, the N3xx corresponds to the ecu used.
N318 is '85-87 JDM 13B turbo with auto trans,
N319 is same series with 5-speed trans.
Both use low impedance injectors with a ballast resistor block.
N340 is '88 13B turbo with manual trans and high impedance injectors and no ballast.

 

There is no automatic Cosmo for the counter weight to exist, not 100% sure about the R100 as well. The only auto 10a was the RX3 10a - mainly Jap wagons. There are 2 or 3 part numbers in the book, and no number stamped on the counter weight... (not that anyone would be interested in this anyway )

 

That's a lightweight.

 

digging up an old nearly dead one,, and setting some of it straight,, and adding some more curly questions
( see bottom of post about the front mass ID's )
can anybody with a recently stripped engine confirm my ID's of the front masses
or add to the debate of those missing from the list ?
( taken from my collection,, some of these stripped many years ago so rely on distant recall )

ima pretty sure about the 13b ones,, but not 100% on the ID and year differences on the late 12a series,, particularly whats happening year wise between N201 and N226 for the front masses

AFAIK

N319 is the AUTO,, N318 is the manual
( 1986-early 87 jap/ aus 13bt ECU codes )

1029A stamped on a rear weight indicates its for 74-85 13b rotor masses
( the only rear weight that has any ID stamped on them )

-- over the years later ones may only be stamped 1029, then 29 then sometimes nothing
the best identifier -
the inside edge rim flats ( without chamfer ) will measure between
11.68 to 12.14 mm wide


measured thus -





my rear weight ID data ---

89-95 13B
-N351-11-5210---------12.52 to 12.85 mm


86-88 13B
-N327-11-521A--------13.23 to 13.92 mm


76-85 13B
-1029-11-751A--------11.68 to 12.14 mm
( NB older versions may be stamped 1029A, 1029 or 29 )


83-85 12A
-N226-11-751A---------6.07 to 7.01 mm



79-82 12A
-1883-11-751A-------- 8.25 to 9.17mm
------------------------------

my front weight ID data ---


1881-11-511 ,,4 port 12a 74-80
1.3kg, 26.5 mm thick 180 degree mass , no chamfer, marked cast "B" on either one of the mass edge flats
for use with 12a flywheel with wide outer mass ring
or for use with 1883-11-751A rear auto counterweight



-----------------

N201 -11-511,, 81-82 12a rx7
1 kg, 29.7 mm thick mass with approx 100 degree angle, parallel edges on the mass with no chamfer edge
intended for use with rx7 8.5 clutch / flywheel with small outer ring mass
( marked cast 21 on flywheel rear )



-- is this including 12a six port and 12a turbo and aus s3 12a with 9.0 ( 225 mm ) flywheel and clutch )?
anybody with definite pics and dimensions for N226-11-511?

---------------------------

74-85 13b stamped 1757 ( a 1974 rx4 13b code )

1.3 kg ,28 mm thick 180 degree mass, no chamfer edge , cast "I" or dash stamped into one of the flat ends of the mass
sometimes marked 1757 also with an unrelated factory number
( this one marked F356 )



NB
- some sources say only suit 74-83 and quote N304-11-511 for 83-85 13b
( although 13b rotor masses are unchanged 74-85 )
other sources quote N304-11-511 as replacement for 74-85
( as 1757-11-511 is NLA from mazda )
as such consider that N304 and 1757 weights are interchangeable
------------------

N326-11-511, s4 13b ( and 13bt ) ,, 1.3 kg , 26.0 mm thick , 180 degree mass, small chamfer edge 8mm wide,, fine machine grooved finish
------------------

N350-11-511,s5 13b ( and 13bt ) ,,1.2kg,23.4mm thick, 180 degree mass, small chamfer edge 5mm wide, fine machine groove finish,, small torrington surface
( as distinct from FD large torrington thrust face surface )

 

bump-----------

my front weight ID data ---


1881-11-511 ,,4 port 12a 74-80
1.3kg, 26.5 mm thick 180 degree mass , no chamfer, marked cast "B" on either one of the mass edge flats
for use with 12a flywheel with wide outer mass ring
or for use with 1883-11-751A rear auto counterweight



-----------------

N201 -11-511,, 81-82 12a rx7
1 kg, 29.7 mm thick mass with approx 100 degree angle, curved sides yet parallel ends on the mass with no chamfer edge
intended for use with rx7 8.5 clutch / flywheel with small outer ring mass
( marked cast 21 on flywheel rear )




---------------------------
N226-11-511,, 83-85 12a, 12aT
1 kg, 29.7mm thick mass with 80 degree angle, straight edge, ends still 80 degree angle
intended for the 9.0 flywheel /clutch combo





---------------------------
74-85 13b stamped 1757 ( a 1974 rx4 13b code )
consider that N304-11-511 for 83-85 13b and 1757 ( for 74-78 ) weights are interchangeable
( 1757 is NLA )

1.3 kg ,28 mm thick 180 degree mass, no chamfer edge , cast "I" or dash stamped into one of the flat ends of the mass
sometimes marked 1757 also with an unrelated factory number
( this one marked F356 )




------------------

N326-11-511, s4 13b ( and 13bt ) ,, 1.3 kg , 26.0 mm thick , 180 degree mass, small chamfer edge 8mm wide,, fine machine grooved finish
------------------

N350-11-511,s5 13b ( and 13bt ) ,,1.2kg, 23.4mm thick, 180 degree mass, small chamfer edge 5mm wide, fine machine groove finish,, small torrington surface
( as distinct from FD large torrington thrust face surface )

 

n225 is 6 port 12a

 

THANK YOU BUMPSTART!!! I had a pile of front counterweights and needed to ID the S4 one.

 

BUMPSTART is the man...how about 13B counterweight writeup?

 

this helps me id the years of parts laying around. What about a flywheel ID chart?

 

Honestly, I need some help identifying things as well, as I got a bunch of what I believe are 12A parts from a fella who didn't know what went to what and now it's my turn to figure out what it all is. I have a TON of **** from this guy, including a set of 13B housings which say Mazda Aviation Division on them. I'll post in FS/Wanted soon when I get some more of this stuff identified. I have LOADS of pictures.

I have two counterweights, both fronts, both 180 degree weights. One is marked and other is not in any way shape or form.
How about a 1757 front weight with what looks like 3L20 stamped on it? I have an eshaft that has the same 3L20 and a YZ on it. Using a metal drafting ruler because my calipers are missing; ~27.5mm thick, 1.3kg, two holes drilled in the centre of the outside edge of the weight [I can explain better with pictures], no chamfered edges, flat side is cast and stamped with an A. And like I said, I have the eshaft that goes with it. This is the marked one.
The unmarked; ~25.5mm thick, 1.2kg, one hole drilled into the bottom outside edge. On this weight, all edges on the actual weight are chamfered to a certain degree on the Y and Z axes, meaning just the curved edges on inner front, outer front and back, and chamfers on the outer edges on the ends of the weight. This weight is only cast on the opposite edge as the weight. The front and back are smooth. I can provide pictures.

EDIT: I also have the unmarked eshaft for the unmarked rotor. I need to learn to identify those too, as well as these older housings. Like I said, most of these are 12A parts, I think.