Everything you would ever want to know about Mazda gearboxes

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mazdawat
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Re: Everything you would ever want to know about Mazda gearboxes

#316 Post by mazdawat » Thu Apr 03, 2014 9:27 pm

almost half way through this thread and its doing my head in a little. i will continue reading it all, but all i want to know is if a s4 13bt motor will bolt up to a 12a series 1 rx7 gearbox?? and if it doesnt, do i need to change the starter, clutch flywheel etc.

i know its not the ideal box in the slightest. just need to know if it fits. :|

luke


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Re: Everything you would ever want to know about Mazda gearboxes

#317 Post by sir-revalot » Thu Apr 03, 2014 11:02 pm

Yeah, will do. S4 turbo has a bigger flywheel and clutch. But yes they will bolt up. As far as shifter placement and mount placement goes it all depends on car and engine placement. Mine was fine with the S1 clutch and flywheel as the later 13b rotors are similar weight to the early S1 12a ones.


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Re: Everything you would ever want to know about Mazda gearboxes

#318 Post by mazdawat » Thu Apr 03, 2014 11:57 pm

thanks for the reply!


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Re: Everything you would ever want to know about Mazda gearboxes

#319 Post by mazdawat » Fri Apr 04, 2014 11:13 pm

13b bell housing that suits a celica 5 speed, can it be used on a s5 13bt box? i dont have any more info on the bell housing other than it suits a 13b and a celica box.


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Re: Everything you would ever want to know about Mazda gearboxes

#320 Post by sir-revalot » Sat Apr 05, 2014 6:15 am

Umm :-k NO...

Unless it has the adapter plate in between bell and box, then its probably a S4 one with adapter to Toyota or a Rx4/5 one with adapter.


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Re: Everything you would ever want to know about Mazda gearboxes

#321 Post by mazdawat » Sat Apr 05, 2014 10:31 am

sir-revalot wrote:Umm :-k NO...

Unless it has the adapter plate in between bell and box, then its probably a S4 one with adapter to Toyota or a Rx4/5 one with adapter.
Thanks that clears it up perfectly. My thoughts were on par with that but needed confirmation! Cheers.


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Re: Everything you would ever want to know about Mazda gearboxes

#322 Post by Syd » Thu Jun 05, 2014 9:18 pm

Hello,

I am restoring an r100, will likely put a 12a twin dizzy in it, top mount starter. I am a little confused about the types of boxes.
The most important part is getting the shifter through the original hole.
Am I better to use the r100 box or the 12a top mount starter box?
Can I put rx4 internals/ratios into the twin dizzy box?
Can I convert the twin dizzy box to a 121?

Thanks,

Syd



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Re: Everything you would ever want to know about Mazda gearboxes

#323 Post by bumpstart » Mon Jun 16, 2014 10:44 am

changing between 10a or 12a will involve shifting the engine 20 mm on the crossmember so that the position of the bell housing ( and shifter ) does not alter between the two

for the r100 shifter position you will need to run a box with the typical piston position shifter

usually this was the 121 box ,, fitted with the rx2 or rx4 12a twin dizzy rotary bell housing ( with input shaft front modified )

a modern equiv could be done using the type R box ( 13bt ) and fitting the entire rear third housing found in some 88 + later bravo utes ( and twin dizzy bell housing )
( or the entire bravo box with a modded front input shaft )

which should bring a shifter position further forward than the typical rotary rx2/4 /s1 position
( but requires a custom ford/ mitsu clutch combo and a custom tailshaft as these are not out of the box the same as r100/ early rotary )




fitting an rx2 twin dizzy bell amounts to top starter.. using the 73 rx4 bell housing amounts to a bottom starter

none of the single dizzy bell housings are compatible to your block., and thus rules out all the M type gearboxes as found in rx7 s1- s3

if you was using an SD block .. then the solution would be the M box with a third rear housing fitted up from the 1985 B2000


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Re: Everything you would ever want to know about Mazda gearboxes

#324 Post by ex | machina » Sat Mar 07, 2015 11:30 am

A challenge for the experts. I have a 65 Mazda ute and looking into doing away with the pistons and dropping a 12a in it but I'm really keen to keep it 4spd manual column shift (for personal nostalgic reasons), however I am not even sure if it's at all possible at this stage. The standard piston gear box is clam shell 6 bolt type. Will I need a twin dizzy or single dizzy 12a (I currently have a single dizzy lined up) and some old school R100 bell housing perhaps? Maybe a newer column shift box from a different Mazda might be the go. Is any body able to provide some insight?
Kind Regards
Last edited by ex | machina on Sat Mar 07, 2015 5:29 pm, edited 1 time in total.



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Re: Everything you would ever want to know about Mazda gearboxes

#325 Post by sir-revalot » Sat Mar 07, 2015 2:41 pm

Mitsubishi and Ford like to use Mazda boxes too. Maybe something from a Ford or Mazda van might work as some are cable and some are linkage operated. Might be able to change the bell housing and extension housing on the van box to retain a gearbox mount below the box rather than above it like most van boxes are. Just need to put a plate over the shifter hole.


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Re: Everything you would ever want to know about Mazda gearboxes

#326 Post by ex | machina » Sun Mar 08, 2015 10:33 am

sir-revalot wrote:Mitsubishi and Ford like to use Mazda boxes too. Maybe something from a Ford or Mazda van might work as some are cable and some are linkage operated. Might be able to change the bell housing and extension housing on the van box to retain a gearbox mount below the box rather than above it like most van boxes are. Just need to put a plate over the shifter hole.
Thanks for that. Certainly something to consider. On page 1 of this thread there is a paragraph relating to van gearboxes which states that the ratios would be highly unfavourable but I'm just after a Sunday cruiser so might be an option after all.



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Re: Everything you would ever want to know about Mazda gearboxes

#327 Post by Zero » Sat Mar 14, 2015 1:19 am

bumpstart wrote: fitting an rx2 twin dizzy bell amounts to top starter.. using the 73 rx4 bell housing amounts to a bottom starter

none of the single dizzy bell housings are compatible to your block., and thus rules out all the M type gearboxes as found in rx7 s1- s3

if you was using an SD block .. then the solution would be the M box with a third rear housing fitted up from the 1985 B2000
Think Im in the same boat, I have RX2 TD with top mount starter. Its running 4sp and I would like a 5sp, so RX5 box is my only option?


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Re: Everything you would ever want to know about Mazda gearboxes

#328 Post by bumpstart » Sat Mar 14, 2015 2:12 am

a TD bell housing should also be able to bolt onto the 13bt gearbox as they are all "R" types
( s5 and FD gearbox is same pattern onto the bell but with 2 extra studs which you delete/ignore when using the s4 or rx2/4 bell housings )

a 13bt gearbox is going to need the cut shut on the shifter turret position
and also may not have the stick entirely upright if using the early bell
( 13bt and 13btt gearboxes also require a different tailshaft slip yoke )

so the rx5 5 spd is going to make the stick pretty much in the right spot for all the old schoolers
( except r100 which will require the 121 extension housing and shifter )
and still use the same tailshaft you have now

your other option is to leave the 4 spd in there ( tough and reliable ) and fit yourself the 3.7 diff from a 626 rwd
effectively it will gear the engine down in top gear a fair bit and 2nd gear will be 110 kmh if you ring it out


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Re: Everything you would ever want to know about Mazda gearboxes

#329 Post by Zero » Mon Mar 16, 2015 1:02 pm

Thanks for the reply mate. Yeah I was hoping to go the other direction as in closer gear ratio's of say a s1 or s2 box but have my pie too by having the 5th gear for cruising. The other week at street drags my car was crossing the line in 3rd at 90mph. The 3rd gear just seemed way too long. Are the S1 and s2 boxes R type? I know about shifter position on s2's...


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Re: Everything you would ever want to know about Mazda gearboxes

#330 Post by bumpstart » Mon Mar 16, 2015 4:25 pm

R types ( rx2/4 4 spd, rx5 5 spd, FC 13bt, FD ) have the separate bell housing with a cluster case behind it ( with flat bottom plate )

M types ( s1,2,3 and s4/5 NA ) have an integral bell housing that when separated will expose the gears

R types are particularly strong, used even in some ford bronco's
.. but only the rx5 box is an easy / direct retrofit to oldschoolers originally with the 4 spd R box
else for others you need to move the shifter , and it may not be upright when used with some bells
and the later ones need a different slip yoke to your original , and may need a custom/ ford / mitsu clutch disk for some flywheel combos

M types are not strong,, and only the s1 box retrofits to oldschoolers without any mucking around with shifter
they do all however share the same slip yoke to your current 4 spd

there is significant strength improvements to the 12at and the s4 NA M box versions
if you want a sweet box that will shift at high rpm in NA applications, these are fine

they do not however like launches with slicks


when the going is hard, don't retard, remember your lubrication
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