Jump to content

Mazda gearboxes.......


Recommended Posts

Yes to all the above I guess. Sadly

Removing the handbrake was where i got to with the TR gearbox in my other Spitfire. Although putting that back together always seemed a uniquely frustrating activity what with springs, and various bits all wanting to move in separate directions. Fly-off handbrake might have made that slightly worse.

At one point I was taking out engines and or gearboxes with such regularity that I finally had enough and put the Spitfire heater box back in :wallbash:

Lot to be said for keeping the original installation, though much of that is quite rude....

Link to post
Share on other sites
  • Replies 74
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Have now finished the adapter ring. Quite happy with the way it turned out. There was a certain amount of fettling required for the final fit but once that was done it dropped into place nicely - and,

Hello Nick                  How about a stretched limo look? The Satnav had locked onto this? but the view was worth it and me and the Memsahib had a nice picnic and a nice ice-cream on the

Unmolested box in the background. Easy conversion moves the remote forward the distance between the bolt holes - 104mm. (yellow) I think you could just about get 175mm and retain the original sele

Posted Images

NB (mk2) mx5 uses an electronic speedometer. It's a straight swap over and may make life easier. The oe triumph speedometer faceplate is easy enough to redrill to accept the mx5 innards (you take off the printed circuit board and hardwire directly to the component plate which sounds harder than it actually is) I have done it with the mx5 tacho which will be essentially the same. Triumph needle will require gluing as the hole is a tad bigger than the mx5 needle shaft. No idea how the gauge sweep compares however

image.png.70b58954f5929dbdcde7b2d9eb743691.png

Link to post
Share on other sites

Thanks for the reminder about the electronic sender Arlo. I do have an NB box stashed - will have to check to see whether there is a sensor in it. Mind you, it’s so tight in that area, I’m not sure there’s even room for the sensor.

I’m not blind to the attractions of the standard kit - simply mend and refit for example. But I’ve had such a lot of hassle and disappointment from small chassis gearboxes....

Link to post
Share on other sites
1 hour ago, Nick Jones said:

I’m not blind to the attractions of the standard kit - simply mend and refit for example. But I’ve had such a lot of hassle and disappointment from small chassis gearboxes....

tumblr_lbp6y1kooo1qz6f9yo1_500.jpg.1b8bb5ace2d597248d4ae810434596b6.jpg

Thanks Bruce. Got that particular T shirt.

And been there with the debate, different outcome each time too :blink:

Mazda box looks good though Nick and given the effort to date seems a shame not to finish it.

Link to post
Share on other sites

This evening we have an MX5 box that bolts up to a Triumph 6 pot and has the gear lever centre line 580mm from the bell housing face, which is actually 5mm shorter than the Triumph box. What’s more, 5 gears, plus reverse, select sweetly. Reverse is still way too easy to get from 5th though, so I’m not there yet. Once that is resolved I can finish welding the frame up and make some closing panels. I’ve also got various sealing issues to overcome.DEE21C8B-5E62-4631-B4C7-982BF830BD64.jpeg

E88C5C3D-4A53-47E0-AAEE-A38BDAD3FA84.jpeg

std mk 1 MX5 left, victim in the centre and Triumph with Dtype OD on the right.

403B33F3-2D86-444B-ADEE-EADB39D55532.jpeg

36D33F12-4EC1-4A05-9E7D-2BF440CCB534.jpeg

A25DED6A-B18D-4AB0-8703-2019EE058725.jpeg

24A060CF-7E72-43F8-9DC6-BD91DA86CEB8.jpeg

  • Like 1
Link to post
Share on other sites

Been bumbling on with this.  I'm still struggling with the reverse lockout.

Looking again at the selector block I remembered that I'd semi-purposely left a step in the side (even the correct side!) in case I needed to add an extra detent plunger. 

IMG_5369s.jpg

It seemed like I did need an extra detent plunger......

IMG_5368s.jpg

...... So this happened.  It was really fiddly getting it tacked in the (almost) right place.  The green arrow shows my first attempt - a simple block that stops the selector moving into R unless it's all the way across.  It does that - but putting it in 5th seems to automatically ensure it's all the way across already so it fails.....

IMG_5371s.jpg

Now, when it gets to the midpoint (ie neutral gate) the extra ramp runs into the new plunger, which makes disappointingly little difference.  Possibly not helped by having subtly angled the plunger so it trails rather than leads, which was the opposite of my intention.  I can also make the ramp more abrupt.

Getting very bored with this selector bollocks now..... and I still don't even know is there's a cat in hells chance of getting the box in the car without major hackery....

Link to post
Share on other sites

So..... time to try and physically get the box in the car.  My experiences wrestling the old box off showed beyond doubt that there was zero possibility of it going in the car unless I either

Take the engine out (Hell No!)
Hack a big chunk out of the tunnel (No - or at least, not yet)
Take the bell housing off

The tape measure said that just maybe, if I took the BH off, I could wriggle the box in far enough (poke input shaft through the starter hole) to post the tail housing into the tunnel.  I spent quite a long time calling the tape measure an optimist, then a liar, then a damn liar..... but in the end, by the power of swear and bit of help from gravity, it did go.  I had to apologise to the tape measure - but that's ok.IMG_5382s.jpg

In place.... ish. The input shaft is poked into the back of the flywheel and the tail housing is resting on the cross member.

It's close everywhere.... really close.....

 IMG_5379s.jpgIMG_5383s.jpg

But although it looks like it's touching, there is about 5mm in both places

IMG_5380s.jpg

Here it is touching, but not by much and not only is there excess casting than can be removed, but it the whole lot needs to go up at least 10mm, probably more.

I popped a jack under the box and propped it up a bit, then spent a few minutes messing with the engine height so the front face of the box was parallel to the flywheel and the right distance from it.  Looking ok.

IMG_5387s.jpgIMG_5389s.jpg

Tunnel even pops straight on, though the back of the selector mech is damn close....

Link to post
Share on other sites

One of my bigger concerns is whether the prop will miss the handbrake bulge.  I have an MX 5 prop and that went straight on, but is considerably too long to be able to lift high enough at the back to prove the point.

I also have a short stump with the plug-in spline and a bit of rummaging produced a piece of propshaft that I think is the original from my Herald.  Minor fettling saw the MX5 part slip inside the Herald one snugly enough to stay put and the whole combination proved to be close enough to the right length that I'm sorely tempted to just weld it all together!  Probably won't though.  Anyhow, good enough that it proves that the prop, even a 3" one, comfortably misses the bulge, even with the box lifted higher than I think it needs to go.  Win!

At this point it's liking like my work so far has not be wasted.  It's also looking like if I want to get the box out again without rupturing myself, something will have to be done about the tunnel.....

IMG_5397s.jpg

Oooh..... err

IMG_5398s.jpg

That's a bit easier......  Will be re-instated in a removable way.

 

Link to post
Share on other sites

Will try it again tomorrow with the BH attached and bolt everything up.  Means changing the backplate for a saloon one.....

The mounting is going to be a serious challenge - if I want to have an exhaust as well........

The speedo drive is another - though I think it might actually be possible with the right angle drive arrangement and some mild re-shaping of the chassis flange.  If anyone has a knackered one kicking about to experiment with........ I'd prefer not to risk killing a known good one......

IMG_5392s.jpg

Must compare rotations between the Triumph and MX5 boxes also.  The W58 turned out to be identical - don't suppose I'll get that lucky twice!

Link to post
Share on other sites
16 hours ago, Nick Jones said:

I had to apologise to the tape measure - but that's ok.

Nice touch. A lesser man would have felt too proud to apologise. 

Enjoying seeing this develop, very impressive. I'd have given up at every stage so far :)

Link to post
Share on other sites

I am probably being unreasonably stubborn about it all. Especially insisting the gear stick comes out in the original Triumph position. Re-inventing the selector mechanism really is a colossal ball-ache.  Moving it forward to the limit of the Mazda mech and altering the tunnel cover and trim would be far less aggro!

Link to post
Share on other sites

Saloon back-plate fitted, bell housing refitted. 

IMG_5400s.jpg

Gearbox wrestled in..... after removing parcel shelf, heater pipes and adjusting heater controls to the most advantageous position.  Tight - damn right.  The BW35 bell is bulkier than the GT6/Vit one.  An only-just-barely squeeze it through.  Going to have to do it at least once more and the very best.... can't wait :pinch:

However, once in, bolted in and raised to a likely-looking running position and there's room all around.

IMG_5401s.jpg

The fat bit of the box happens to land where the chassis isn't. Can actually get my fingers all the way down the side.

IMG_5405s.jpg

and this side is positively roomy....... closest approach just below the bolt head.  Except that I've got to get a mount and speedo drive in there yet..... :wallbash:

Link to post
Share on other sites

all very impressive. It would be nice to use the Mx5 speedo drive but You could do something different with the speedo drive, a couple of magnets on the prop shaft and a hall effect or proximity sensor and then electronic speedo job done.... 

mike

Link to post
Share on other sites
57 minutes ago, mpbarrett said:

You could do something different with the speedo drive, a couple of magnets on the prop shaft and a hall effect or proximity sensor and then electronic speedo job done....

Yep. Plan B...... 

Chris is working on this also as the Jimny & SJ gearboxes have no speedo drive at all (it’s in the transfer box).

He’s been trying to create a dc servo motor drive to drive the original speedo 

Link to post
Share on other sites

perfect project for an Arduino! Had a problem with Libbys Focus dash board and had to take the dash apart all the needles, speedo, Tach ,fuel and temp all driven by small PCB mounted servo motors.

mike

Link to post
Share on other sites
10 hours ago, Nick Jones said:

Yep. Plan B...... 

Chris is working on this also as the Jimny & SJ gearboxes have no speedo drive at all (it’s in the transfer box).

He’s been trying to create a dc servo motor drive to drive the original speedo 

Hi Nick,

when you come up with an electronic speedo drive please share.

I've been trying to rid the behind dash area on my TR4A of wires and drive cables and want to remove the speedo cable.

A couple of years ago I bought a digital thingy that would fit where the angle drive fits on the GB but haven't got round to inventing the end at the gauge.  I was thinking of a DC servo as I want to retain the existing gauge.

 

Roger

Link to post
Share on other sites
  • 2 weeks later...

Yes, Chris is messing about with a DC servo motor.  He's struggling - I think because the the motor is not entirely as advertised (or is ambiguously advertised).

Meanwhile, I've been monkeying at a level I understand - actual bits of metal and gears.  This has been made possible by the generosity of Nuala (aka Greta) who kindly sent me a right angle drive from her parts stash.

This appears mechanically fit, but bears the scars of a PO grinding bits of the body away to try a generate a bit of extra gap between drive and chassis - not a problem for me as I'm likely to need every mm I can find!

This is what the angle drive looks like dismantled
IMG_5424s.jpg

I think it's an aftermarket one rather than OE, with cast iron body.  This actually helped as it turns out as it has the threaded sleeve retained by a spring clip (top right) rather than a peened washer...... though getting the clip out was a mission and provoked some cussing.

These are the parts from Mazda that have to learn to play with the above in the most compact manner possible...
IMG_5425s.jpg

It's trickier than it needs to be due to Mazda (again) failing to anticipate my needs when they designed it.... :rolleyes: So dimensions are just slightly wrong in the harder-to-resolve direction in a couple of places.

IMG_5437s.jpg

Most awkward of these is that the end of the Mazda speedo cable needs to be a light press fit inside the  gear - but is already slightly too small.  Slightly enough to make the creation of a sleeve challenging but too much for loctite etc.  The nose of it and the gear-shaft (right) also need to shortened as much as possible as I need to sit the nose of the right-angle drive as far into the gearbox socket as possible to miss the chassis.

IMG_5436s.jpg

Also, the nose of the angle drive is slightly too small in diameter and needs a sleeve making. Also thin wall but should be do-able.

Ought to be sorting the rear mount first so I know how much room there is to play with, but it seems I have tennis elbow.  This has been lurking for a while but recently I seem to have tipped over the edge so that almost anything I do with my right hand needing more than a light touch a). hurts alot & b) makes it worse.  So I'm trying to behave......  Haven't played tennis for about 35 years either :wallbash:

So I've ordered a propshaft from Dave Mac and been talking to others about speedo calibration.  Needless to say, Mazda are less obliging than Toyota and offer the choice of 3.83 or 3.66:1 for the speedo drive when the original is 3:1.  This means that I need a speedo TPM of either 846 or 866.    The original 1152 was 6% out anyway due to the 3.63 diff.  I'm told that 840 or 860 are possible but are in "km territory".  Speedograph Richfield are front runners at present in both attitude and cost.  Could probably sort it myself if I could locate the right gear(s) but no one will sell them.

In theory there are Mazda combinations from other incarnations of that gearbox family (RX7, rwd 626 , 929 and various pickups) that would give near enough the right result.  The pitfalls are accuracy of information, availability and a significant risk that the spiral drive gear will be the wrong hand due to the speedo drive being on the left on most of these gearboxes while the MX5 is on the right.  Fortunately I happened across a sad story about this on the internet before being over-tempted to try anything smart myself!

 

Link to post
Share on other sites
1 hour ago, Nick Jones said:

but it seems I have tennis elbow.  This has been lurking for a while but recently I seem to have tipped over the edge so that almost anything I do with my right hand needing more than a light touch a). hurts alot & b) makes it worse

Owwwwww!!

Having just finally kicked the same into touch myself (taken a couple of months) I appreciate how painful this is! First occured for me onboard, where fortunately I had an oiler who was a wizard at massage (damn useful guys those Filipinos!) who had it sorted in minutes.

May be worth finding a suitable sports massage person who can have a go? If your current covid restrictions allow of course....... It is truly amazing what a bit of massage can do for tennis elbow, you can take my word for it.

I am watching this gearbox thread with great interest, whilst hoping that you haven't forgotten the injection manifold you were building (I may most likely be pilfering your design ideas on that!)

Phil

Link to post
Share on other sites

Yeah, something like 4% of cases have anything to do with actual tennis I think I read....

Most common among people who work with their hands..... My grip is shot - can’t pull plugs out or get the lid off anything.... 

I haven’t forgotten the ITB manifold..... but I have bigger problems just now, mostly self-inflicted :rolleyes:

Link to post
Share on other sites

Nick- I have done the same thing.

I know what you mean about the mx5 cable being too loose in the right angles sleeve- I thought about it and ended up filling the gap with rtv. I know it is bound to fail eventually, but I figured I'd see if it worked for any length of time before using solder in the gap. The idea was that the rtv would fail before the nylon gears stripped or the right angle seized.

Other option could be to build the mx5 cable up with solder and file down to size. 

I've no idea if it'll work yet as I haven't run it. 

FB_IMG_1607028884001.jpg

FB_IMG_1607028915549.jpg

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...