rx 4 automatic to manual conversion

[bumpstart]

well,, i doubt it

it will have the right ends,,,but i very much doubt its the right length

the ONLY time i have seen a successful lego in terms of tailshafts from piston to rotary
is for rx2,,, of which the 929 single shaft can be used to replace the rx2\'s two piece
( which is in no way an upgrade,, just an alternative,, the two short pieces are much better balanced than any long single can be )

since the rx2 has a shorter wheel base than the rx4
 and the 808 a shorter wheel base than either
( and has the longest engine/ gearbox package hence shorter shaft than an rx3 )
then i highly doubt its going to be anywhere near the correct length for the rx4

and before you ask,, s1/2 rx7 is a very very short single tailshaft
and so are all the vans ( which will also bring a different uni size in most cases )
and the b2000 ute,,
( which will be incompatible at the rear flange  for the big 30 spline diff )
-far too long with a 75 cm front section ( yoke to yoke )
that also brings different uni\'s to boot to prevent you using just the halves


if you could just measure your current 3N71B auto for us in length
- then we could confirm that its about 5cm wrong at the slip joint
and then we could weigh up the alternatives better

[dr50376272]

i sourced a 12a turbo and 5 speed for US$330 from yahoo auctions japan with computer and original 68000km.

so, as for tailshaft, which will work? whats the shifter mod that needs to be done?

regards

rx7 s1 -3 is a shorter , single piece shaft ,, your rx4 one should be a long two piece unit
IIRC only the rx5 is going to be compatible ,, and then you must match 12a to 12a,, 13b to 13b
as there is a different uni at play,, and a different pinion flange for 13b tailshafts

ie,, if you have the 12a rx4,, only the 12a rx5 ( japan market only rx5 ! )
is going to be close unless you ship the pinion flange from the 13b diff with a 13b tailshaft

( i would still measure them to be sure,,, i am running on recall that the pans underneath are mostly the same basis )


as is,, i think the OP has taken a different route,, instead finding a rare 12at engine and box as a drop in fit
( aside tailshaft lengths and shifter mod )
-- which,, all those years back,, was my very first mod rotor project ,, a 12at into a rx4 13b LE coupe
( circa late 1991 )


-- very straight forwards, near drop in fit, and a great engine to boot for streetable power
( its all down low with that tiny turbo and hits a wall at 6500-7000 rpm )

normally,, for most the 12at isnt on the radar for options
( being a very tricky engine to source intact out of japan )
but IMO,, probably the easiest option with a very good result for the effort
( if you live in japan ! )

[bumpstart]

tailshaft = manual rx4 or manual rx5 ,, or custom
shifter mod-

 method to shorten the shifter housing for s1 rx7 ( and earlier rx\'s )
( same method is used on s2/3/4  M boxes as for the s4/5 turbo R boxes )

note-- the below quote is mine from another forum
- and is in fact about the s5turbo box
the method however is identical
though please ensure that your box has the 103mm spacing between the holes before you cut shut anything and adjust accordingly

and PS
any \'M\' box can easily exchange its entire third rear section of the box with any other,, including piston types
-- you just need a pin punch to help swap the selection rod fork ends
to suit the new rear section
( you must put the box into reverse to help you split and re-assemble the box rear section )

for s5 box in short -
remove the shifter extension housing
( including removing the roll pin holding cup to the shaft inside, drill and tap it though or pull it )

cut it off at the second row of bolts ( retaining the second set of bolt holes , now the front set )

remove fixing dowels ( for the selector housing ) from the box
and diagonally cut off the rear left set of hole alum castings on the box with cut off grinder
( to clear the bump on the underside of the shifter housing when moved forward 103mm )
[img=http://img52.imageshack.us/img52/4879/pic0630484.th.jpg]
[img=http://img101.imageshack.us/img101/8868/pic0630486.th.jpg]
 shorten the outer tube and inner selection rod by 103mm
carefully measure retap the rod for a new roll pin or a grub screw ( 6 x1.0 is what i do )

bolt it together
[img=http://img42.imageshack.us/img42/5782/pic0614450.th.jpg]
-- shifter housing comes forward one full set of mounting holes (103mm) and is aprox 25 mm short of the original s1 /rx4 box stick position
( so fits all the early rx\'s except s2/3 rx7 and r100 )


[img=http://img101.imageshack.us/img101/6024/pic0630483.th.jpg]

[img=http://img6.imageshack.us/img6/8131/pic0630485.th.jpg]

[img=http://img52.imageshack.us/img52/1331/pic0630487.th.jpg]

[Rivalrx]

Cheers mate!

[Rivalrx]

I got the RX4 auto prop out today (left) and put it next to the 626 one for a length comparison as it needs to be longer to mate with the RX7 series 1 box of mine. Box not in the car and I\'ve binned the auto so measuring is an issue.

Hopefully it fits - will find out in a few weeks...not holding my breath however it may work out?



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