Do all 20B's have codes?
 

Hey guys,

I bought a 20B today,

I went to see if it was an A B C coded block etc..

but the housings have no code stamped on them..
I can tell the engine has had some work done to it in the past..

is it possible it was rebuilt with new housings that don't have codes?

or is it something else?

I looked for the code on the top of the Housing next to where it says 20B.. but the flat space where the code should be is simply blank.

any ideas?

any ideas?[/QUOTE]

Check the sideplates.. all of them should be stamped with the code and # TOO.. on the tops.. easiest to see on the rear iron..next to that spot where water can pool up in the little pocket on the top of the casting

Post a pic of the longblock

I can usually tell which genearation from the pics

I thought replacements had no code, but I am going off memory from selling a few a long time ago

There is a series that has no code on the housings, the ones Mazda rebuilt under warranty, but the plates will all have codes on them, like japan2la points out. Just look at any plate and you'll see.

I got one off ebay a few months ago and it was rebuilt and had brand new housings. It was a c series.

Granted I was looking at it in the dark with the light from my iPhone. But I tried feeling around the surface for the etchings but couldn't feel any

I took a couple pics earlier in the day but hadn't thought of checking the code till later

I can post them up but their only a couple shots from the exhaust/intake side of the motor

dunno if that will do u any good tho

it seems like at the factory ALL of the housings got stamped on top with the #

if you bought a replacement housing it will not be stamped.

i have seen (well we own it) housings where the number is ground down, not sure why this would happen, maybe if you rebuilt it with used parts?

for example my 20b had the number 246 on all the irons and rotor housings. pauls motor is c263 (or something) but he's got a couple of housings with ground numbers.

pauls NEW housings have no number.

so when we get around to building the 3rd engine, it'll be blank

here's the pics: dunno if it's worth a look tho...

when the engine gets shipped to me, i can take it apart and take a better look at it..

but I'll tellin ya there's no codes on those housings.. and they weren't ground off...



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Check the irons, NOT THE HOUSINGS. The irons will have a stamp on them and the are all usually seen from the other side than what you have taken pics of. Look closely and you will see them.

I would need to see the otherside..

BTW: that motor previously already had a Single turbo conversion..

ahhh ok.. sorry my bad.. I coulda swore in pics it was on the aluminum housings...


does anyone have a pic of where I should look?


when the engine reaches me by the end of the week i can take another look properly this time


yeah man I noticed that heat shielding on the OMP and the oil return adapter and block off plate..

all the houses were redone and has new check valves as well...

the engine has compression on all 6 faces as well..


I guess the wreckers or someone already scavanged the turbo kit...


but I still picked it over another stock one I found...

hoping that it was once overhauled before the single turbo conversion, and maybe it has bigger injectors in the rail still...

see this is the codes I was looking for:

http://www.3rotorrx7.com/images/20%2...ls_inplace.jpg

Yes, those are codes for sure BUT they are also stamped on all of the irons or the red parts in the pic. Each piece (irons and housings) usually has a code stamped on it but if the engine has been rebuilt then the housings might not have codes on them. For example, my engine is C339 but I have brand new housings so the housings no longer have codes on them. But all of the irons still do and you can see the code on each easily.

thanks David..

how is the 20B in stock form?

do I HAVE to put FD (REW) housings in it?

i would rather not open it if I didn't have to since it appears to have been rebuilt once already..


i can see the ports are noticably smaller then the FD counterparts...but Can I still use it as is?

how badly does it choke the motor in this form?

at what point is dowelling and re-enforcing the block necessary?

if i do leave the housings/porting stock (assuming it hasn't been already since it once single turboed) should I go down in turbo size as well? or stick with the usual GT42 size's..

i'm more interested in a less stressed less strung out 400-450whp motor that I can DD in my FD...

most of my knowledge is the the FC and FD motor.. the 20B is still a new ball game to me.. and i realize that it has some diff "rules" to it..

thanks

Here is a pic of my engine. We replaced two rotor housings and the thin intermediate so they are not stamped. You can see the D303 on the front, thick int. and rear irons.

No, it is not necessary to replace the housings with FD housings, simply pull the exhaust sleeves and replace them during the rebuild.


http://www.banzai-racing.com/20B/Eng...ebuild_top.jpg

http://www.banzai-racing.com/20B/Eng...uild_front.jpg

Thanks for the clarification and the pics

But what I meant is if I don't open the motor at all and use the sleeves as is how "bad" is it? Do the housings cripple the engine's top end badly?

I would not install any used engine without rebuilding it first. Every 20B and 13b-re we have built we have ported and swapped exhaust sleeves, so I can not tell you just how badly it will effect performance.

I agree with Banzai on this one - rebuild the engine. Why go thru all the trouble to get a 20B and then have problems because you didn't know the actual condition of the engine? And if you go single turbo, you need to port then engine anyway. It's possible you'll open up the engine and not much will need to be do to it but do it anyway as it will pay off in the long run.

The 20B flows much better than a 13B so a GT42R or equivalent is a pretty good choice for you. If you keep the boost down (read less stress), say at 12 PSI or so, you'll easily be in the 475 WHP range. Trust me you are going to want to turn up boost a little more than this as the turbo won't be close to its efficiency at that level but for daily driving it is pretty fun. Don't go higher than 18 PSI and the engine will be fine.

Figure out what series engine you have and then we can answer the "doweling" question although the better route is the Guru stud kit so read up on this. Studding isn't really needed at the power levels you want but I would recommend it if you have one of the weaker engine series - the A or early B codes or the ones that have no letter but just numbers.

Thank you for the assistance so far guys...

I'll get back to you on the series Q when the motor arrives (the truck that was transporting it blew it's engine lol)


u're right .. anyway u look at it.. rebuild is always better... i wont argue that point..

but it's a huge PITA and expense... ( I don't know any other car guys that do it tbh, all the ppl I know with 2J swaps and RB's and SR20's and 4G's all throw their JDM engines straight in)

I live in the middle of no where, and do all my own motor work.. i've overhauled my 13b-T and REW before... the expenses of shipping in housings and other heavy parts adds up fast..

not to mention I don't have the SST to remove the lobe of the e-Shaft

and the garage where I do all my work at is trying to evict me, and I haven't found another place that I can work freely on my motors and stuff...


my intention was to get the motor on the car.. and crank it over see what kind of compression it makes.. and then do an ATF or Water treatment on it to clear whatever Carbon and Junk I can to "freshen" up the motor.. and see how she fairs...


anyways..

I was going to start a new thread for this question but I guess I can post it here..


my current dilemma at the moment.. is How to mount the motor...

i've done alot of searching.. and alot of the threads are 4-6yrs old.. and I don't know which companies went bust, many links are dead etc..

I know of 3 options

1.) custom subframe (Aspec, hinson, petit)
2.) stock subframe relocate acc. Defined autoworks style
3.) stock subframe, stock acc. custome bonnet..


in here lies my dillemma...

I want to retain the A/C at the very least.. PS i can live without...

Defined auto:

I live on the other end of the world.. so shipping my intake and oil pan and other components to the states, wait 3-8 weeks then have em shipped back..

Pro's: stock subframe.. no bumpsteer

cons:
engine sits higher
and it's $2,000 + the shipping expenses



Hinson:

everything works fine no need to ship anything to them.. just order the subframe with
bumpsteer correction and goto town..

pro's..

engine sits lower, less shipping expenses.. (only 1 way shipping) subframe is $1,200
I will have the subframe in a week rather than 2 months
stock mani, I can retain AC and PS functions




cons
i've read sometimes it doesn't correct the bumpsteer altoghether
there's a possibility I may fail visual inspection with the custom subframe


3.) Custom bonnet

pro's
stock subframe (no bumpsteer)
stock intake
retains acc.
much cheaper


cons
engine sits higher Like the defined kit
cusomized bonnet might turn out looking like crap or other aesthetic issues

I have a authentic Mazdaspeed vented bonnet that I refuse to hack or modify in anyway..



is that the 3 options? did I miss anything?

I'm leaning towards option #2 at the moment...

but I would like to hear from you guys what your thoughts and opinions on the matter are..

Rebuilding the engine is one of the less expensive portions of this conversion, especially considering you are doing it yourself. You can not compare a JDM rotary to a JDM piston engine. The piece of mind of knowing everything is within spec when turning the key for the first time is worth the added expense.

There are parts in the 20b that are know to fail, like the intermediate iron stationary gear bearing. The engine can have compression but the bearing could still be toast , these are the things you find out when you open it up.

I prefer the aftermarket subframe route, not fond of chopping the LIM or the angle of the engine with the other options. That is just my opinion.

Understood... opening the engine it is after all...

ppl were talking about 4k for a rebuild and what not.. so i was abit shocked..


which subframe do u suggest? I've noticed u went the hinson route..

but you never really did a follow up.. the engine was still breaking in last I read

are you guys happy with it?

Ours is a customized version of the Hinson, we changed a few things and had it E-coated.

Now that Winter is over we can finish the break in, just put insurance back on the car a couple days ago. The car is absolutely fantastic, I enjoy everything about it. Should have it on the dyno later this month for power tuning.

well the motor is finally in my hands..
but I'm still confused.. :(

i tore down the motor to a keg..

the housings all say 20B and all 3 are rears..

no codes stamped on them

LIM has been ported and gasket matched..

spark plugs look brand new as well..

all good news so far..

here's the weird part..

either I'm blind or missing something

my irons don't have a Letter.. only a number as far as I can tell..

it says 681 on them..

I guess my original question still applies.. Do all 20B's have codes?



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I did some more digging..

(found the thread accidently without searching for it.. our search engine is terrible)

according a post from DMRH..

the reason i don't have a letter is cuz my engine is SO old.. it's PRE letter coding
:(

it's one of the early weak ones

*sigh*

You are correct sir, the "681" code does predate the A-D and then number codes. That is an original engine. Maybe some of the engine builders can chime in here but my marginally learned opinion is that engine would be fine for a NA application or if you want to go turbo, then use a Guru stud kit on it and I would think you would be okay at a low boost level.

So if I don't stud it and leave it stock then it's a paper mâché mock up of a 20B
if I add the stud kit. The. It's only weak and good for low boost applications?

Bloody hell

I am sure some experienced engine builders can help you here. It is not a desirable engine in any event as it has known weak spots. However, with a rebuild and s stud kit, it can be used. As for how much boost, I don't know the answer to that.

What does each A B C code stand for?
Is there a difference in each engine?

The stud kit u refer to, is it higher tensile strength stock sized bolts? or are they the enlarged diameter ones requiring machining?


does the fact that my engine has been remanned give any possibility that the weakness have been remedied?

or is the inherint flaws of the iron castings something I have to live with..




the codes refer to the production series of the engine..

0-999 First batch
A001-A999 2nd
B
C
D

etc

with the C and D being the best "oem" engines to buy

They require machining to work:

http://www.rotaryonline.com.au/store...products_id=42

As I understand it, the weakness is in the iron castings so this is something you'll have to live with unfortunately. It's been a while since I researched this as I have "C339" or one of the better engines.

Thanks david for all your replies and ur assistance..

the thing that worries me is that I live in a pretty simple country that doesn't have fancy equipment for this kinda stuff

I can't get my irons nitride coated, I can't get my rotating assembly balanced, and I don't know if the stud kit requires special skill set either... I might end up making my perfectly running 20B into an expensive door stop :(

My 20b doesn't have a number.

at all? or only on the housings? did u check the irons?

if it has 3 of the same rotor housing, R or whatever, then its been rebuilt. but they reused the irons.

an ORIGINAL engine would have F,C,R rotor housings, AND the # stamp. but hey new rotor housings are good things

as for the non number engines being weak, yes the later engines had stronger irons. how much this matters depends on the hp goals, if its reasonable 300-450hp, then its probably ok as is.

i had #246, and it was a good engine

Yeah man, thats the only good news so far.. and the fact that it has black paint on the housings means it's a factory Reman I blieve.. (hopefully they used good internals and not bad ones)


ur 300-450hp is that at the crank or the wheels?