Jcmac Posted June 9, 2021 Report Share Posted June 9, 2021 Hi Marco, thankyou for your kind response. I made more room above the bellhousing by reshaping the heater box but this is different on a Midget so there maybe more clearance. This means without a large hole there is no unusual noise, except quieter I had to make a cut-out for the starter motor but manage to keep the original motor. I also uses some aluminium sheet to create a cover over the starter motor gear for safety and to keep out water and dirt as much as possible. After looking at concentric release bearings, I was able to adapt the clutch release arm to operate the clutch to keep the problems "outside" this time. The Midget has a full length transmission tunnel which will not accept the MX5 gbox so I removed the bottom as necessary and also the front floor cross-member but then added a replacement bolt in lowered crossmember to replace the strength. I had to cut away all torque tube mounting which is quite tedious, then I shortened the prop-shaft about 150mm and rewelded with no noticeable balancing required after test driving. We are fortunate here not to have a TUV looking quite so close but we do need to be safe and well engineered. We can justify a gbox change on the grounds of efficiency without affecting the TAX and MOT status, i.e no MOT or TAX required after 40 years old (with certain exception but I have carefully consulted the DVLC website) The gearing for the MG is fantastic... almost identical for 1,2,3,4 and then overdrive for 5, and so slick. The original box did not have syncro on 1st so my daughter found it a bit tricky and the noise was terrible. I had bought a low ratio differential to get better cruising speed which VERY low in a 1275 Midget 60mph max comfortable but now 75-80after a bit of a run up Actually not too bad if you use the revs. NOTE: I have just measured my MG gearstick position at 660mm from the bell-housing flange for your interest. This could be made a little less (maybe 10-20mm) by cutting deeper into the gearbox and a little more off the turret and a thinner mounting block. I think this would stop the need to cut cut the H tunnel cover but you might need to do something more if you want it right in the centre again. I guess you could use steel angle to reduce that to maybe 6mm from 12mm but this may lose some rigidity and affect the gearchange. Apologies for the long post and please excuse my grammar even though English is my first language! regards, John PS I have included a few photos which may be interesting, I was not nearly as good as you at keeping a photo history as I was against a deadline of 6 weeks in NewZealand, a thing of distant memory.... Quote Link to post Share on other sites
Tim D. Posted June 10, 2021 Report Share Posted June 10, 2021 8 hours ago, Jcmac said: Hi Marco, thankyou for your kind response. I made more room above the bellhousing by reshaping the heater box but this is different on a Midget so there maybe more clearance. This means without a large hole there is no unusual noise, except quieter I had to make a cut-out for the starter motor but manage to keep the original motor. I also uses some aluminium sheet to create a cover over the starter motor gear for safety and to keep out water and dirt as much as possible. After looking at concentric release bearings, I was able to adapt the clutch release arm to operate the clutch to keep the problems "outside" this time. The Midget has a full length transmission tunnel which will not accept the MX5 gbox so I removed the bottom as necessary and also the front floor cross-member but then added a replacement bolt in lowered crossmember to replace the strength. I had to cut away all torque tube mounting which is quite tedious, then I shortened the prop-shaft about 150mm and rewelded with no noticeable balancing required after test driving. We are fortunate here not to have a TUV looking quite so close but we do need to be safe and well engineered. We can justify a gbox change on the grounds of efficiency without affecting the TAX and MOT status, i.e no MOT or TAX required after 40 years old (with certain exception but I have carefully consulted the DVLC website) The gearing for the MG is fantastic... almost identical for 1,2,3,4 and then overdrive for 5, and so slick. The original box did not have syncro on 1st so my daughter found it a bit tricky and the noise was terrible. I had bought a low ratio differential to get better cruising speed which VERY low in a 1275 Midget 60mph max comfortable but now 75-80after a bit of a run up Actually not too bad if you use the revs. NOTE: I have just measured my MG gearstick position at 660mm from the bell-housing flange for your interest. This could be made a little less (maybe 10-20mm) by cutting deeper into the gearbox and a little more off the turret and a thinner mounting block. I think this would stop the need to cut cut the H tunnel cover but you might need to do something more if you want it right in the centre again. I guess you could use steel angle to reduce that to maybe 6mm from 12mm but this may lose some rigidity and affect the gearchange. Apologies for the long post and please excuse my grammar even though English is my first language! regards, John PS I have included a few photos which may be interesting, I was not nearly as good as you at keeping a photo history as I was against a deadline of 6 weeks in NewZealand, a thing of distant memory.... Looks nice. I also have a re-gearboxed midget. The more common ford type 9 conversion mated to a rover k series. Bundles of fun! Quote Link to post Share on other sites
Nick Jones Posted June 10, 2021 Report Share Posted June 10, 2021 Hi Marco, Great to see see you have it all working. Just a little project for next winter to tidy up the console area so it matches the perfection elsewhere. Are you liking the way it drives? JcMac, squeezing an MX5 box in a Midget is no small task either! Good work. Cheers Nick Quote Link to post Share on other sites
Z320 Posted June 11, 2021 Author Report Share Posted June 11, 2021 Hi Nick, thank you and YES: I like driving it very much, this will make long distance trips on the Autobahn much more compfortable. This is comming up very soon for a trip to Austria. I'm also very pleased about the engine noice when idling, this was never a pleasure, as I realize (and told already) because of the noisy TR gearbox. My "air heating from the engine" is now very limited after I did a modification, What I have to become used to is the different noice of the mazda gearbox while driving on 1-2-3, and what I have to look for is to close the holes in the gb bell. Btw: shifting the gears is indeed shorter than on the TR gb - BUT only the sidward way from 1-2 to 3-4, not sideward to 5 and not backward and forward. Ciao. Marco Quote Link to post Share on other sites
Z320 Posted June 11, 2021 Author Report Share Posted June 11, 2021 (edited) Hi John, that's very interesting what modifications you had to make for your Midget. And the standard Mazda friction disc d=200 mm and the Aisin DZ-008 did not fit? Ciao, Marco Edited June 15, 2021 by Z320 Midget, not Sprite Quote Link to post Share on other sites
Jcmac Posted June 14, 2021 Report Share Posted June 14, 2021 Hi Marco, sorry for delay in reply. Thanks for your interest. I had searched the internet for suppliers of clutch plates but failed to find a suitable part. I had not heard of Aisin but have looked it up and it is interesting. I will check it out to see if 200mm will fit inside the MG cover plate. This would be so much easier if I need to replace it or if I do another for friend who is interested. I will keep you informed. Many thanks. John Quote Link to post Share on other sites
Z320 Posted June 15, 2021 Author Report Share Posted June 15, 2021 (edited) a quick search on the www tells me there are at least 3 different sizes of friction plates for the Midget, All smaller than 215 / 200 mm: 6 1/4", 6 1/2", 7 1/4"... Which size is yours? I have to look at home, I remember having the Aisin part list for Mazda on my private computer. Edited June 15, 2021 by Z320 Quote Link to post Share on other sites
Z320 Posted June 15, 2021 Author Report Share Posted June 15, 2021 sorry, can't find it Quote Link to post Share on other sites
Z320 Posted July 3, 2021 Author Report Share Posted July 3, 2021 Hi there, after 1.800 km with the MX-5 gearbox I can tell you some news. It still works without any problem and I'm mainly pleased about. But the noise out from the holes of the chopped bell are "irritating", I have to close them next winter. The heating from the cut out of the gb tunnel and gaiter was like a 2,000 Watt heardryer, I "closed" them with pieces of soft foam from above and below. Here a look with the gaiter removed for the photo. From below with "sausages" of soft foam sidewards and around the rear end. With this the heating is like a heardryer with "only" 500 Watt.....perhaps I try to move the shifter in the correct position next winter. The movement of the gearbox to the engine is only about 2-3 mm, as the o-ring shows, my worry was unfounded. Very pleased I'm about my speedo drive: it still works and compared with Google maps on 300 km distance it is only 3% "shorter", that's OK for me. Well, that's it for today. Ciao, Marco Quote Link to post Share on other sites
RogerH Posted July 4, 2021 Report Share Posted July 4, 2021 Hi Marco, to reduce the heat flow from around the gear stick why not fit a simple gaiter https://www.moss-europe.co.uk/catalogsearch/result/?search_group=&q=gear+stick+gaiter Roger Quote Link to post Share on other sites
Z320 Posted July 4, 2021 Author Report Share Posted July 4, 2021 (edited) Thank you Roger, sadly that doesn't work because the cut out of the tunnel cover for the shifter housing and the housing reaching through...... Edited July 4, 2021 by Z320 Quote Link to post Share on other sites
JohnC Posted July 6, 2021 Report Share Posted July 6, 2021 On 7/4/2021 at 6:41 PM, Z320 said: sadly that doesn't work because the cut out of the tunnel cover for the shifter housing and the housing reaching through. Gaffer tape. Pretty sure WD40 won't work, so Gaffer tape it must be Quote Link to post Share on other sites
Lou s A30 Posted August 11, 2021 Report Share Posted August 11, 2021 (edited) Hi Marco. and others... I am fitting an MX5 gearbox to a 948cc A Series engine in my 1954 Austin A30. I have driven it once. It works well. I have it out again to check and fix some issues. One was being certain that I had engine and gearbox lined up properly. Researching this issue I came across your incredibly informative post. Reading it gave me a lot of pleasure. It made me feel like I was going through it all again. Your idea of using a temporary brace to check alignment of input shaft and spigot bush worked great and proved that I was spot on the first time. Being a member of the Austin A30 A35 Owners Club in the UK has allowed me to post my A30 journey on their forum. This is the link http://forum.austina30a35ownersclub.co.uk/viewtopic.php?f=10&t=12022 **** (NOTE.... The above forum is going through a website upgrade and migration. ) Regards. Lou (Lou's A30. Australia) Edited August 11, 2021 by Lou s A30 More info Quote Link to post Share on other sites
Z320 Posted August 11, 2021 Author Report Share Posted August 11, 2021 (edited) Hi Lou, great to hear from you from Down under! Do you know what is the most amazing about? How a guy from Germany with his TR4A and a guy from Australia with a A30 find together... By the internet and via a forum - opened for everybody to read and see all photos! Crazy, isn't it? Ciao, Marco Edited August 11, 2021 by Z320 Quote Link to post Share on other sites
Lou s A30 Posted August 12, 2021 Report Share Posted August 12, 2021 Yes Marco, it's amazing. In my lifetime it's gone from writing letters ( 6 weeks) to a small phone in the hand ( instant). Some photos Quote Link to post Share on other sites
Tim D. Posted August 12, 2021 Report Share Posted August 12, 2021 6 hours ago, Lou s A30 said: Yes Marco, it's amazing. In my lifetime it's gone from writing letters ( 6 weeks) to a small phone in the hand ( instant). Some photos Lou, looks great. I've done a similar conversion on my midget albeit with a ford type 9 gearbox and k series engine. Your photos really show just how short the original gearbox is. Quote Link to post Share on other sites
Z320 Posted August 12, 2021 Author Report Share Posted August 12, 2021 Great photos, telling everything (most of it)! Same job, but different details. Sadly the link to the A30/35 forum does not work. Do I have to register and lock in there? Quote Link to post Share on other sites
Lou s A30 Posted August 13, 2021 Report Share Posted August 13, 2021 (edited) On 8/11/2021 at 10:45 PM, Lou s A30 said: *** (NOTE.... The above forum is going through a website upgrade and migration. ) Hi Marco. I will let you know when they have it up and running again. You won't need to register or log in to read it. Regards. Lou Edited August 13, 2021 by Lou s A30 Spelling errors Quote Link to post Share on other sites
Lou s A30 Posted August 13, 2021 Report Share Posted August 13, 2021 14 hours ago, Z320 said: (most of it) Marco, Yes it is as long as yours on my forum post. Quote Link to post Share on other sites
Lou s A30 Posted August 13, 2021 Report Share Posted August 13, 2021 On 8/12/2021 at 5:01 PM, Tim D. said: Lou, looks great. I've done a similar conversion on my midget albeit with a ford type 9 gearbox and k series engine. Your photos really show just how short the original gearbox is. Yes Tim, the MX5 gearbox is bigger than the engine too. Unless I had read an article in Austin A30 A35 Owners Club magazine I would not have thought it possible to install it in an A30. But it fits well. Lou Quote Link to post Share on other sites
Z320 Posted August 13, 2021 Author Report Share Posted August 13, 2021 58 minutes ago, Lou s A30 said: Hi Marco. I will let you know when they have it up and running again. You won't need to register or log in to read it. Regards. Lou Sorry me, German saying is: "Who can read has an advantage" Indeed this is the case. Quote Link to post Share on other sites
Lou s A30 Posted August 14, 2021 Report Share Posted August 14, 2021 Hi Marco. I meant you can read but not post as a guest without joining. The link is now working. http://forum.austina30a35ownersclub.co.uk/viewtopic.php?f=10&t=12022 Regards. Lou Quote Link to post Share on other sites
Z320 Posted August 14, 2021 Author Report Share Posted August 14, 2021 Interesting how you make the propshaft, I was not courageous enough to go that way and was "pleased" to find the u-joint on the MX-5 sliding yoke slightly worn. Quote Link to post Share on other sites
Lou s A30 Posted August 14, 2021 Report Share Posted August 14, 2021 Hi Marco. Glad to see you taking an interest. I have an engineering background and a do anything attitude. I take great pleasure in achieving. Propshaft and flywheel/pressure plate are being balanced so I will see how well I did. Regards. Lou Quote Link to post Share on other sites
Z320 Posted August 15, 2021 Author Report Share Posted August 15, 2021 (edited) To do everything yourself on old cars and motorcycles is more than 50% of the fun with them.... Edited August 15, 2021 by Z320 Quote Link to post Share on other sites
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