My RX7 gearbox
Nevo
car and pulled apart after getting stuck in 3rd gear and not coming out.
Fresh motor with more power and a change from 2nd to 3rd at around 9500rpm
seemed to cause the problem. Thing is, myself and the mechanic can't find a
thing wrong with the box and it free'd up as soon as we broke the nuts
holding the case together. Has anyone else experienced this? I fear it will
do the same thing as soon as we put in back unless the problem is fixed.
Thanks in advance
Nevo
Andrew Sandersos
Andrew
Andrew
and when it cools down its ok again.. Best solution is to
use synthetic g/box fluid like castrol syntrax which is more
expensive but is better for hi-po cars. Of course it might be
a totaly different problem you have but using the better oil
certinaly wont hurt and will make it last longer...
Andrew
"Nevo" <k...@netcon.net.au> wrote in message
news:3a5d...@news.iprimus.com.au...
Aaron T
after he took it home and left it overnight it was fine.. he hasn't had a go
with it for a while now :)
Nevo <k...@netcon.net.au> wrote in message
news:3a5d...@news.iprimus.com.au...
snab
Nevo <k...@netcon.net.au> wrote in message
news:3a5d...@news.iprimus.com.au...
Nevo
is in a different position and it requires modification to fit?
Nevo
"snab" <sn...@bigpond.net.au> wrote in message
news:d1h76.55393$xW4.4...@news-server.bigpond.net.au...
Nevo
time before but I threw the clutch wiggled the stick and it popped out. But
this time it was stuck there quite firmly. The gearbox oil does make a big
difference, my old aussie 4spd used to be sticky in second gear until I
changed to a better oil and it made a huge difference.
Nevo
"Andrew" <0...@mindless.com> wrote in message
news:3a5d439e$0$15467$7f31...@news01.syd.optusnet.com.au...
Ben A
"pretend" ur interested in a new box to buy off em, suggest a S2 box, then
ask em if itl line up.. theyl be able to tell u!news:3a5e...@news.iprimus.com.au...
snab
the workshop and sounding interested. Nice trick there Ben.
*Mental note*
Chad
Ben A <bac...@adel.tafe.sa.edu.au> wrote in message
news:3a5e...@duster.adelaide.on.net...
Colin Smith
missing) and the shaft the gears rotate on got skewed slightly. Loosening
off the housing maybe allowed it to free up. Long shot, but...
Or maybe a slightly bent selector fork or selector shaft?
Colin.
"Nevo" <k...@netcon.net.au> wrote in message
news:3a5d...@news.iprimus.com.au...
Sean
Series 2 gearbox is different shifter position.
Best option is:
(early RX4 4 speed or 5 speed bell housing) +
(Series 5 Turbo G/box) +
(Holden 1-tonne pressure plate) +
(2litre Sigma clutch plate) +
(custom rear cross member) +
(modified tailshaft)
This will also need the shifter modified. Rotomotion in Perth converted mine
neatly and cheaply, giving me the slickest and strongest box (better than a
supra)...
Mine was fitted to a series 1 RX7
"Ben A" <bac...@adel.tafe.sa.edu.au> wrote in message
news:3a5e...@duster.adelaide.on.net...
Al
Is your mechanic an apprentice?
>
>Thanks in advance
>
>Nevo
Al
The Raven
"Al" <braindea...@hotmail.com> wrote in message
news:3a6020f...@news.onthenet.com.au...
> On Fri, 12 Jan 2001 02:19:26 +1100, "Nevo" <k...@netcon.net.au> wrote:
>
> >Ok rotary fans I have a question. My series 1 rx7 gearbox is now out of
the
> >car and pulled apart after getting stuck in 3rd gear and not coming out.
Common problem.
> >Fresh motor with more power and a change from 2nd to 3rd at around
9500rpm
> >seemed to cause the problem.
Not surprised considering the RPM and gearbox involved. Do you a have a 12A
or 13B? If you have a 13B stop revving it to 9500RPM, you get eccentric
shaft flex once you pass 8500RPM which isn't good for engine life (worse
case is it could seize). Even with a 12A that's way beyond peak power unless
you're running ridiculous porting (which isn't suited for street use
anyhow).
> Thing is, myself and the mechanic can't find a
> >thing wrong with the box and it free'd up as soon as we broke the nuts
> >holding the case together.
Obviously has he no experience with modified rotarys. The problem is you
over shifted from 2nd to 3rd. Due to either fork wear or excessive force on
the shifter you pushed the synchro gear well beyond where it should be and
as a result the "shift plates" (as Gregorys manuals call them) have almost
popped out and jammed the synchro assembly for that gear. That's why you're
stuck in third.
> Has anyone else experienced this?
Not personally, but it's common in overpowered or worn gearboxes.
> I fear it will
> >do the same thing as soon as we put in back unless the problem is fixed.
It will more than likely happen again, particularly now that they are
probably worn/marked/damaged! Your solution is to get the gearbox rebuilt
and replace all the synchros (definitely 3rd), also check the shift forks
for wear.
To be honest the best solution is to buy a more suitable gearbox AND reduce
the high RPM or abusive shifts.
The high RPM is well passed making any benefit to acceleration and being
abusive on the shift will not make the car go any faster. With over 100 drag
strip runs I can tell you that most street rotarys don't need to go anywhere
past 8000RPM and there is near zero to be gained by heavy handed forced
shifts (actually a paltry 0.02 seconds). By all means shift as fast as you
can but you don't need to ram the shifter into every gear.
Depending on funds, you should try to get the newest gearbox you can to fit.
All the smooth case gearboxes are fairly weak up until the Series IV RX-7.
Look for an M style gearbox (if it can fit depending on your transmission
tunnel type -auto/manual?) which may also referred to as R types in later
RX-7s (IIRC).
Another option is to bolt in a Supra gearbox which is near impossible to
break behind a NA rotary. Several companies sell complete kits and/or
conversion parts. Dellow sell a complete kit and Maztech (Melbourne) also
have a rather neat conversion. Note that the Supra gearbox conversion can
often be cheaper than using a later Mazda gearbox (eg. rebuild, clutch parts
etc, and still may break).
--
The Raven
** Undisputed President of the ozemail.* NG's
** Conqueror of the uunet.* NG's
Nevo
"The Raven" <ws...@crosswinds.net> wrote in message
news:oLW76.596$FC1....@ozemail.com.au...
> Can't see the original post so I'll jump in here.
>
> "Al" <braindea...@hotmail.com> wrote in message
> news:3a6020f...@news.onthenet.com.au...
> > On Fri, 12 Jan 2001 02:19:26 +1100, "Nevo" <k...@netcon.net.au> wrote:
> >
> > >Ok rotary fans I have a question. My series 1 rx7 gearbox is now out of
> the
> > >car and pulled apart after getting stuck in 3rd gear and not coming
out.
>
> Common problem.
>
> > >Fresh motor with more power and a change from 2nd to 3rd at around
> 9500rpm
> > >seemed to cause the problem.
>
> Not surprised considering the RPM and gearbox involved. Do you a have a
12A
> or 13B? If you have a 13B stop revving it to 9500RPM, you get eccentric
> shaft flex once you pass 8500RPM which isn't good for engine life (worse
> case is it could seize). Even with a 12A that's way beyond peak power
unless
> you're running ridiculous porting (which isn't suited for street use
> anyhow).
Firstly, I should have said that the approx 9500rpm was not an intentional
move. In general I wouldn't have pushed above 8000rpm. Infact before it was
rebuilt it wouldn't have gone past 8000 without really pushing it, which I
never did. However after the modifications were done this was one of the
first hard rev's the engine had taken and it just spun much more freely than
I expected. Engine is a 12A large extend port.
> > Thing is, myself and the mechanic can't find a
> > >thing wrong with the box and it free'd up as soon as we broke the nuts
> > >holding the case together.
>
> Obviously has he no experience with modified rotarys. The problem is you
> over shifted from 2nd to 3rd. Due to either fork wear or excessive force
on
> the shifter you pushed the synchro gear well beyond where it should be and
> as a result the "shift plates" (as Gregorys manuals call them) have almost
> popped out and jammed the synchro assembly for that gear. That's why
you're
> stuck in third.
It poped out of gear as soon as the casing bolts were cracked and operated
as per normal before the gearbox was disassembled. He couldn't find any
other problem from then on and wear in his opinion wasn't excessive. I have
trust in his experience as all he does is work on modified vehicles and
rotaries.
> > Has anyone else experienced this?
>
> Not personally, but it's common in overpowered or worn gearboxes.
>
> > I fear it will
> > >do the same thing as soon as we put in back unless the problem is
fixed.
>
> It will more than likely happen again, particularly now that they are
> probably worn/marked/damaged! Your solution is to get the gearbox rebuilt
> and replace all the synchros (definitely 3rd), also check the shift forks
> for wear.
>
> To be honest the best solution is to buy a more suitable gearbox AND
reduce
> the high RPM or abusive shifts.
> The high RPM is well passed making any benefit to acceleration and being
> abusive on the shift will not make the car go any faster. With over 100
drag
> strip runs I can tell you that most street rotarys don't need to go
anywhere
> past 8000RPM and there is near zero to be gained by heavy handed forced
> shifts (actually a paltry 0.02 seconds). By all means shift as fast as you
> can but you don't need to ram the shifter into every gear.
Yes, sorry I should have cleared this up. This was a once off over rev of
the engine and it had never seen the other side of 8000RPM before this one
shift.
> Depending on funds, you should try to get the newest gearbox you can to
fit.
> All the smooth case gearboxes are fairly weak up until the Series IV RX-7.
> Look for an M style gearbox (if it can fit depending on your transmission
> tunnel type -auto/manual?) which may also referred to as R types in later
> RX-7s (IIRC).
> Another option is to bolt in a Supra gearbox which is near impossible to
> break behind a NA rotary. Several companies sell complete kits and/or
> conversion parts. Dellow sell a complete kit and Maztech (Melbourne) also
> have a rather neat conversion. Note that the Supra gearbox conversion can
> often be cheaper than using a later Mazda gearbox (eg. rebuild, clutch
parts
> etc, and still may break).
Yes funds is a problem or I would have converted to stronger box before the
engine went in. It was a situation of see how it goes. And well I guess you
could say that it didn't;-)..Just trying to do the best with what I had at
that point in time. Your advice is much appreciated either way.
Nevo
The Raven
OK, I wasn't sure. It's just that I hear too many people spouting ridiculous
RPMs for rotarys and claiming that the car went quicker as a result.
> In general I wouldn't have pushed above 8000rpm. Infact before it was
> rebuilt it wouldn't have gone past 8000 without really pushing it, which I
> never did. However after the modifications were done this was one of the
> first hard rev's the engine had taken and it just spun much more freely
than
> I expected. Engine is a 12A large extend port.
Hehe, had the same problem when I bought my RX-3. It had a lightweight
flywheel and I was amazed at how quickly it'd spin up.
>
> > > Thing is, myself and the mechanic can't find a
> > > >thing wrong with the box and it free'd up as soon as we broke the
nuts
> > > >holding the case together.
> >
> > Obviously has he no experience with modified rotarys. The problem is you
> > over shifted from 2nd to 3rd. Due to either fork wear or excessive force
> on
> > the shifter you pushed the synchro gear well beyond where it should be
and
> > as a result the "shift plates" (as Gregorys manuals call them) have
almost
> > popped out and jammed the synchro assembly for that gear. That's why
> you're
> > stuck in third.
>
> It poped out of gear as soon as the casing bolts were cracked and operated
> as per normal before the gearbox was disassembled. He couldn't find any
> other problem from then on and wear in his opinion wasn't excessive. I
have
> trust in his experience as all he does is work on modified vehicles and
> rotaries.
OK, you can put the gearbox back in and see how it goes. However, if it jams
again consider replacing it or getting it rebuilt.
OK, sorry.
>
> > Depending on funds, you should try to get the newest gearbox you can to
> fit.
> > All the smooth case gearboxes are fairly weak up until the Series IV
RX-7.
> > Look for an M style gearbox (if it can fit depending on your
transmission
> > tunnel type -auto/manual?) which may also referred to as R types in
later
> > RX-7s (IIRC).
>
> > Another option is to bolt in a Supra gearbox which is near impossible to
> > break behind a NA rotary. Several companies sell complete kits and/or
> > conversion parts. Dellow sell a complete kit and Maztech (Melbourne)
also
> > have a rather neat conversion. Note that the Supra gearbox conversion
can
> > often be cheaper than using a later Mazda gearbox (eg. rebuild, clutch
> parts
> > etc, and still may break).
>
> Yes funds is a problem or I would have converted to stronger box before
the
> engine went in. It was a situation of see how it goes. And well I guess
you
> could say that it didn't;-)..Just trying to do the best with what I had at
> that point in time. Your advice is much appreciated either way.
>
Yeah, I'm strapped for cash myself. The RX-3 has been off the road for
several years but will be far better when it is finished.
Nevo
> > > Not surprised considering the RPM and gearbox involved. Do you a have
a
> > 12A
> > > or 13B? If you have a 13B stop revving it to 9500RPM, you get
eccentric
> > > shaft flex once you pass 8500RPM which isn't good for engine life
(worse
> > > case is it could seize). Even with a 12A that's way beyond peak power
> > unless
> > > you're running ridiculous porting (which isn't suited for street use
> > > anyhow).
> >
> > Firstly, I should have said that the approx 9500rpm was not an
intentional
> > move.
>
> OK, I wasn't sure. It's just that I hear too many people spouting
ridiculous
> RPMs for rotarys and claiming that the car went quicker as a result.
Yeah, I didn't intend to sound like some joker who revs the thing as hard as
it will go all day everyday cause I'm not.
> > In general I wouldn't have pushed above 8000rpm. Infact before it was
> > rebuilt it wouldn't have gone past 8000 without really pushing it, which
I
> > never did. However after the modifications were done this was one of the
> > first hard rev's the engine had taken and it just spun much more freely
> than
> > I expected. Engine is a 12A large extend port.
>
> Hehe, had the same problem when I bought my RX-3. It had a lightweight
> flywheel and I was amazed at how quickly it'd spin up.
Yep, my exact problem. Went from bog stock to extend port, lighten flywheel
exhuast mods and the thing just span off the dial. I thought it would
struggle as it began to peak but it just kept going and took me by surprise.
Great engine though, so much fun to drive.
It has been rebuilt to a degree. I think a couple of things were replaced
but basically was a clean up. I'm guessing the box has never been apart, car
has done 140,000k's which for a 1979 car is not a lot and it was owned from
new by an old guy who didn't drive it hard. If it jams again though it's
going in the bin.
> > > The high RPM is well passed making any benefit to acceleration and
being
> > > abusive on the shift will not make the car go any faster. With over
100
> > drag
> > > strip runs I can tell you that most street rotarys don't need to go
> > anywhere
> > > past 8000RPM and there is near zero to be gained by heavy handed
forced
> > > shifts (actually a paltry 0.02 seconds). By all means shift as fast as
> you
> > > can but you don't need to ram the shifter into every gear.
> >
> > Yes, sorry I should have cleared this up. This was a once off over rev
of
> > the engine and it had never seen the other side of 8000RPM before this
one
> > shift.
>
> OK, sorry.
No worries, I should have been clearer from the start.
> > Yes funds is a problem or I would have converted to stronger box before
> the
> > engine went in. It was a situation of see how it goes. And well I guess
> you
> > could say that it didn't;-)..Just trying to do the best with what I had
at
> > that point in time. Your advice is much appreciated either way.
> >
>
> Yeah, I'm strapped for cash myself. The RX-3 has been off the road for
> several years but will be far better when it is finished.
This car has been off the road for 2 years being fully rebuilt, I just get
the thing running and the gearbox dies. Oh well, fun and games with cars as
per usual.
Nevo
heke...@gmail.com
alvey
> Yes I have the same problem with my s1 gearbox and I replaced it with a new one and the same thing has happened both stuck in 3rd gear did you find the problem with your one as I have no stripped them down and they look fine
Bad news: Arsehole in Merrimu discovered.
If only the latter could be hurled into the former.
alvey
Xeno
--
Xeno