If anything I'd say it was the other way around. The 1-3-2 shaft (if it exsists) seems to be pretty scarce. Giving it a little more thought, look what happens when you expand this order out:

1-3-2 1-3-2 1-3-2 1-3-2

1 3 2 1 3 2 1 3 2 1 3 2

now drop the first '1'

3 2 1 3 2 1 3 2 1 3 2 1

Might as well be 3-2-1 !

So perhaps this is the firing order of a 3-rotor engine when someone calls the front rotor #3 and the rear rotor #1?

My engine is B685. It came out of Japan in 2000 as a pull from a wrecked car. It was minus alternator and trans, and no ecu or coils, but otherwise all there. I got it at a bargain price, so I'm not complaining :D

I think mine is B385 from what I can see through the stamp. Hard to tell though.

i have a "problem" engine and its 1-2-3

mike

its possible the 2 rotor cosmo uses the same housings front and rear, the older engines usually do

mike

as far as i know the firing order was not changed.
j9fd3s> when you say you have a problem motor
what do you mean?

later
matt

hmm... intresting. Thanks.

mine is 246, so according to some people it blew up or was recalled etc, but mine has never been apart, and runs fine =)

mike

my 454 has never been apart and it is running fine
even with some hot running and some hard running
it is still going strong:) the b991 is another story.

later
matt

I just recently double-checked the engine, since I was nearby...
It's actually "A669". :)


-Ted

G'day from DMRH

This is a basic way to understand your 20B engine

000 - 999 = 1st batch
A000-A999= 2nd batch
B000-B999= 3rd batch
C000-C999= 4th batch
D000-D999= 5th batch
E000-E999= 6th batch (only heard of these, never seen one)

I have never heard of an F-series. Since Mazda made just under 4000 20B version Cosmo's I can also picture that the E-series was for warranty replacements if they exist at all.

If the engine has black on the rotor housings & the batch number stamp isn't on there, then its an internal factory rebuilt engine. (meaning its been out in a car & returned after failing within the warranty period)

The last engines to go into a car would have stopped around "D500" for fitment into a Cosmo. For example.........

The last Cosmo sold by Mazda = JCES-100633

However, Mazda quote selling just 369 examples of this series-II version so how it got to #633, I really don't understand.

The latest Cosmo we have ever imported is JCES-100309. Its engine batch # D442 It was a AUG-95 car & production ceased in Sep-95.
If you have any quiries then conact us via http://www.dmrh.com.au

you motor is a early motor # 850 the R means nothing
unless its on the rear rotor housing.
F C R = front,center, rear. any other letters
are just assembly numbers.

matt

I look'd on my motor and all I see is 48 which is stamped next to the 20B on the rear housing but there is an A stamped on the opposite side of the 20B lettering, what does this mean?

that's only on one of the housings?
the A has to be in front of the numbers if its anywhere
else it means nothing to the production time. as far as I know.
if you really have a #48 that has to be one of the
earliest ones I have ever heard of.

matt

See that's what I thought to and as I was disassembling it today all of the other housings have 48 on them also but the strange thing is ALL of the vaccum lines look'd to be in almost brand new condition, none were brittle or old looking and I took most everything off with a rachet, the only thing I used the impact gun to take off was the turbo manifold, and on top of that there was still undried oil in the oil lines, so what the hell is going on? From what I have read, if this is a #48 serial motor then it's one of the first 20B's built and one of the worst models.

I will take some pictures tomorrow and post them to show everyone. Maybe it's been reman'd because the place I bought it from gave me a warranty on compression, I guess I won't know until it's in the car.

had a look at mine in the shop yesterday it is C964

wow a "c" motor your a lucky late production motor
owner!
I was thinking of stamping my 454 motor with a "d"
maybe it would make it a better motor:)
matt

only two rotors were working when I bought it though :(
they freed up the rotor and discovered a cracked seal :(:(

let me now how you go with the stamping it's pretty easy to turn a "D" into a "D" ;)

Ha ha ha!!! No need to stamp mine. I just bought a "D" series #133. :D :dragster: :worship:

I read all the way through this thread so I could confirm my understanding of this subject. My Cosmo, with VIN JCxxxxxx439 (meaning the 439th car - it's a 1990 20B) has engine 503 - no letters. The car has 146000 kms and it is running just fine. Of course this is a completely stock car and appears to have never been abused. I also have an engine I picked up in case #503 decides to stop working. It's brand spanking new (what a find!!!) with no run time, ever, It is D642. All of this supports what Dave Morris stated in his post. Just additional info for the board...

Your Cosmo being JC-439 with engine 503 says its the original engine.

I can remember Cosmo JCESE-100826 with engine A003. Meaning a few engines where getting put aside for warranty replacements as production went along.

The fact that your "suspect" series engine is still going at 146,000km is the first I have ever heard for these early engines surviving this long. Proving there is always an exception to the rule.
We are currently getting JCESE-100330 back onto the road after its "suspect" series failed. Have found a "warranty" engine for it. Meaning black paint on the rotor housings & no production number stampings...... (E-series..???)

My personal Cosmo is JCES-100190, engine D321

Re: DMRH
 

The 3-rotor 13B featured in the pic for the EVIL-7 engine is not a 13G. A 20B is closer to a 13G than this engine.

The short shaft 3 rotor parts is supplied by Precision engineering in Auckland, NZ. They can do a 4 rotor shaft & parts too for those that are interested. Alec Bell from Kiwi-RE is assembling that particular engine.

Remember, the 20B was built in "batch runs" hence the production numbers. (eg D321 for a 95 Cosmo like mine) With the 13B manufactured in the tens of thousands as a series production motor. You wont find production numbers on it. It would be too difficult for them.

If you find one with no-numbers beside the "20B" stamp, painted black in that section too. Chances are its a WARRANTY motor. Meaning you would have a good engine as these may be the "E-series" engines that I have heard of but never seen.....

I'll know my number as soon as I get it. I can't wait. :)

2x 20B
 

Well I'm now the proud owener of 2 20B's :-)

Picked up a street ported motor with Mazda 3mils, new bearings and a nice looking L/W flywheel yesterday which a guy was selling due to abandoning an FD->20B project. Never been run, looks mint, turns over nicely :-)
Number is B170.

It's now sitting on the workshop floor next to my stock 20B, number C278 :-)

Gonna chuck the stocker in my FD with a GT42/45 running low boost to start with while we iron out all the inevitable install gremlins. Then swap em over and think about buying a guys RX4 that has no firewall left where some genious was going to dump in a chevy block :-(

All good :-)

Rich
UK

That RX-4 is gonna be awesome! I'm doing a Cosmo/RX-5.