How to Build a Simple MX5 Chain Drive Differential - No Machining, No Welding

** Now with Subtitles**
How to build a cheap and easy Mazda MX5 based, chain drive differential using basic hand tools.
No lathe or welding required.
The video shows the conversion of the 1.6 and 1.8 Mazda MX5 (Miata), open action differentials from the NA & NB series cars (up to 2005).
Note: NC models have a different differential with larger bearings (which are difficult to find suitable sealed replacement bearings).
The same build techniques can be applied to other differentials including some aftermarket limited-slip differentials (LSD) such as the Blackline HLF030 Mazda MX5 (NB), ATB LSD.
I used self-aligning bearings which combine the bearings with circular flanged, pressed steel housings SBPF207 for differentials with 35mm bearing spigots or SBPF208 for differentials with 40mm bearing spigots. Typically 40mm simplybearings.co.uk/shop/p23...
or 35mm simplybearings.co.uk/shop/p23...
The output flanged, stub shafts come with the MX5 differentials. The ones on the 1.6L MX5 have (4)10mm bolts on a 100mm pcd for MX5 bolt-on CV joints.
1.6L open differentials use different output shafts from 1.6L VLSD LSDs (different splines and lengths).
The output flanges on the 1.8L (Torsen) MX5 have (4) 10mm bolts on a 110mm pcd for bolt-on MX5 CV joints.
Alternatively, 1.8L MX5 (up to 2005) can have conventional push-in type CV joints/axles rather than the less common flanged type output shafts. The 1.8L flanged output shafts can be replaced by the push-in type CV joints.
The distance from output flange to output flange is 240mm for the 1.6L differential and 278mm for the 1.8L differential.
The sprockets are custom made and are available from www.bandcexpress.co.uk
The dimensions for the smaller 6" MX5 (1.6) differentials are: Centre hole 96mm diameter*, fixing hole PCD 114mm (8) holes 10.5mm diameter equispaced.
* Increase centre hole size if you are fitting the sprockets over the lubricant retaining can*
The dimensions for the larger 7" MX5 (1.8) differentials are: Centre hole 108mm diameter*, fixing hole PCD 134mm (10) holes 10.5mm diameter equispaced.
* Increase centre hole size if you are fitting the sprockets over the lubricant retaining can*

[@bikeroftheeverywheres864]

Weeks and months of searching led me to this video, thank you Sir for laying everything out in an easy to understand way!

[@DougsShed]

Glad it helped!

[@johnkoury1116]

@@DougsShed I have to say that I did not know what I was looking for at first but then. I found this video everything clicked. Thank you.

[@tminer2110]

If this hasn't blown up yet it will soon! I'll play my part! Awsome vid and thanks

[@petecort5446]

Amazing work, I'll be transferring some of your tips to my self build lsd diff, I turned a 10mm plate and threaded to allow attachment of the cup(welded) one side and the sprocket the other 👍

[@RoadWarrior427]

Ingenious!!! I really appreciated this vid. I would have never thought of this on my own. Thanks for sharing!

[@alexx09RO]

Wow - the part where you suggested using an oil filter as a casing was just amazing. Never would come to my mind! Nice one!

[@DougsShed]

Glad it helped!

[@tonyd7164]

FANTASTIC ! thanks for doing all the R&D. cheers

[@alexbuckley1748]

Absolutely brilliant, the best diy fabrication video I've seen in a long time.

[@DougsShed]

Glad you liked it!

[@beardedbaldguy4359]

You have the best and easiest example on the internet period. Thank you so much for sharing your knowledge and wisdom with us! I’m doing a krosskart build. This will be how I do the rear end.

[@bokicar1]

Omg, this is fantastic! I didn't finished the video and I already ordered second hand mazda diff. Thank you very much!

[@DougsShed]

Glad I could help!

[@joell439]

Wow - thanks for all the details. Just found your channel and this first video I’ve seen immediately deserved a subscription. Looking forward to seeing the rest of your content. 👍👍😎👍👍

[@DougsShed]

Glad it was helpful!

[@zezoner]

Thank you for sharing this. I love your precision and your detail. Cheers

[@DougsShed]

Thank you for your kind words.

[@jamesandonian7829]

Amazing idea!!!! Literally, overkill for any go kart! I love it

[@davidelliott5843]

Sidecar outfits don’t turn well in any gear. ;)

[@bjwest6618]

Always enjoy your videos and your willingness to share knowledge. Most appreciated.

[@DougsShed]

Glad to help

[@ecobogan238]

Very cool mate, am looking to do this on an off road buggy. Great to use existing, much cheaper and well designed components that are in the millions lying idle worldwide. Keep it up

[@ptyatas4380]

I definitely could have used this 2 years ago before I mad a straight axel go-kart rear end for my miata kart powered by a gsxr1000 motor, definitely genius work my sir

[@magnon1975]

Thanks for sharing your ideas ! So useful to fellow builders.

[@DougsShed]

Thanks - That's why I posted the video....

[@danielkarrington8983]

You make it look so easy

[@aliterogasolini6401]

Great, thanks for sharing. The art of tinkering in your shed is still alive and well. Will subscribe now.

[@DougsShed]

Thanks 👍

[@bigsquatchsasfoot1964]

This is genius and well thought out my good man and actually exactly what I was looking for ( being to thick to think of something this clever myself) thanks so much for sharing appreciate it very much 👍

[@DougsShed]

You're welcome!

[@11green11]

Amazing enginuity ! Thanks for sharing such a priceless and useful hack 💪😎👍

[@DougsShed]

My pleasure!

[@michaelmayo3127]

That what I like to see, no puller, just a crowbar and a club-hammer, always get the job done. Bravo Mr. Yardex!! The sheet metal-man. Great Video.

[@DougsShed]

I go by the old adage "Everything in the toolbox is a hammer!"

[@lonestarsherp7560]

Great video, very easy to do now I have to come up with a project to put that in.

[@DougsShed]

You should!

[@ToxicSocietyTroll]

I don't need one, but sure enjoyed you teaching me how to build one if I do! Thanks for sharing your knowledge!

[@DougsShed]

Thanks for watching!

[@icouldntthinkofagoodname7216]

Now I have to change the design for my crosskart. Good thing I haven't started buying parts yet lol.

[@blackpit3147]

Very well! Cool idea! I really like it! I love these designs, especially home built ones! Big like! Definitely a Subscription!

[@DougsShed]

Thank you! Cheers!

[@derkaderka808ify]

Get out of here!!! That was amazing!! Very well described !! Thankyou kind sir for sharing your knowledge!!! Thankyou

[@DougsShed]

You are very welcome!

[@frotobaggins7169]

there may not be a welder or a lathe here but there sure is an experienced, skilled hand or two. good video.

[@mouseinthefalls7836]

Totally awesome.... Now I can go make my own for an electric 4x4 go cart. Thank you sir for your time and information on this.

[@DougsShed]

Go for it!

[@mouseinthefalls7836]

@@DougsShed , As I build my project I will be posting videos of it, until then I will do my research on parts and if you like you are very welcome to check out the few videos that I have and offer your suggestions if you wish.

[@lekomato]

great video Doug, Thanks!

[@DougsShed]

Glad you liked it!

[@lesafighter]

you sir are a genius :D

[@Platypus2048]

Awesome video! Thank you so much for sharing this!

[@DougsShed]

Glad you enjoyed it!

[@chrisbilton]

Hi there I’m so gutted you retired in April I’ve just done a slight bit of research on you , this video is quality !! I’m not to steady handed etc and would much prefer to pay someone to make one for me with the housing like on westgarahes site , if you could point me in a direction to buy one built I would me appreciate it or even the one out the video 🤣 thank you Doug inspires me so much

[@benjamindavidson632]

Makes sense. I had a similar idea for an off road buggy I wanted to build. I was going to use a whole rear subframe to keep it as cheap as possible. What I planned to do was weld the miata diff and install a chain ring instead of the ring gear and cut windows in the case to allow the chain to pass through.

[@DougsShed]

It may be difficult to get a large enough diameter sprocket to fit in with the windowed Miata differential case. You could still use the complete subframe etc and mount the simple MX5 chain drive unit to the subframe.

[@beanvo9924]

It’s amazing how he just drill things and it worked. It looks easy but man if you did something like this before, you’ll know how hard it is.

[@DougsShed]

I have made a few of these before!

[@dkryptonut]

Really appreciate you sharing this. Been wanting to do a DIY one of these for a while and this will help me a lot!

[@DougsShed]

Glad it was helpful!

[@johnkoury1116]

Beautiful!!!! I am going to start building one of these for a mini dump truck for homeowners and construction teams. Thank you for the idea.

[@DougsShed]

Sounds like a great idea.

[@johnkoury1116]

@@DougsShed I just located two Rebel 500 motors that I am going to use for the mini dump truck. They are chain drive so I am still going to have to build one or two of these. I am thinking about building a 1/2 to 3/4 size dump truck to use around the farm and put it up for sale but I believe that it will sell so fast it will make my head spin. At least that is what people tell me who hear me discuss the build. I found the coolest thing on marketplace. It is a Drill press and tapping press station that is from an old machine shop that closed sometime after the Second World War and stayed locked and sealed. I was privy to the family opening it and I made them an offer and they accepted it. I am going to try and start my KZbin channel with a short video about it. U will send you a link when I make th video. Thanks brother.

[@firstlastname99]

You're an excellent instructor here at the University of KZbin. Thanks for the instruction.

[@DougsShed]

Glad to help

[@ROVITTv]

Amazing work

[@DougsShed]

Thank you! Cheers!

[@chuckvoss9344]

thank you, for sharing this detailed information with us.

[@DougsShed]

You are welcome!

[@jasoncampbell4723]

Awesome video. Thanks for sharing.

[@DougsShed]

Thanks for watching!

[@johnconnors4127]

Cracking stuff mate.

[@DougsShed]

Thanks.

[@EngineeredToDesign]

Absolute genius! I just planned a whole new build AWD vehicle and completely overlooked the fact that I would need at least a front differential otherwise it would be very difficult to drive! Thank you

[@DougsShed]

You might even need a centre differential to avoid axle wind-up between front and rear (if running on paved surfaces).

[@White_Night_Demon]

@@DougsShed so you would need 3 differentials in total? One for front, one for rear and one for the center for a AWD system?

[@DougsShed]

@@White_Night_Demon Have a look at Dennis Palatov's blog on his build of his 4wd sports car prototype www.dpcars.net/dp1dsn/dd.htm

[@DougsShed]

@@White_Night_Demon Have a look at Dennis Palatov's blog on the build of his 4wd prototype www.dpcars.net/dp1dsn/dd.htm Full blog here www.dpcars.net/dp1dsn/

[@White_Night_Demon]

@What's going on in Doug's Shed? thanks will check it out - been meaning to make my own ratrod that has 5 mode steering(Front, rear, all wheel, same direction and off - just for fun haha), 3 mode driving system (front drive, rear drive and all wheel drive, I believe 4WD only lets you choose either FWD or RWD but can't do AWD?), and it'd also have the option to be pedal powered (Which is why the differential is chain driven rather than a propellar shaft)and or driven by a small engine (I was thinking maybe a 2 stroke one cylinder(so I dont have to worry about changing the engine oil every so often since it gets changed when I fuel up altogether), or that yamaha 4 stroke four cylinder engine with crossplane crankshaft motobike engine (since I like its exhaust note hehe), or if I can get someone to build me one, a 2 stroke small engine v8 that is built from 8 separate chainsaw or weed wacker engines haha since no small engine 2 stroke v8 exists which means it'd have to be custom built and tuned and with a crossplane crankshaft too to boot - and that'd sound awesome!). The pedal power will most definitely help when I run out of fuel for the small engine or if it dies for whatever reasons! Hahaha I'll also see if I can use some bike gear sprokets set on the differential and add a derailer so I can fine tune the the speed on the fly like on a bike! The bulk of the torque and speed changes will be on (maybe custom built unless I can find one that fits a small engine that is also not heavy...) 3 speed + reverse gearbox that connects the drive from the pedals or the small engine that sits at the front of the ratrod. I was thinking of using plastic PVC tubing for basically the whole body and frame, those tubes you use for plumbing for light weight (And have a higher power to weight ratio when using the small engine...) but I dunno if that'll hold up, especially when I go offroading onto rocks (well small rocks obviously, I doubt I'd be able to climb big ones...hahaha) or speed bumps or whatever that isn't smooth... i have seen a few builds here on youtube where they made go karts out of them PVC piping so it must hold up, right? Hahaha But yeah, that's my plan. WIll first need to design working prototypes for each part of the vehicle before I make the real thing to actual scale for use on the ratrod.

[@johng5295]

Thanks in a million. Great content. Awesome imagination. Grade: A++💥

[@DougsShed]

You're welcome!

[@SEILLC]

I need one of these, probably the 1.6 version. Perfect size for my project. I'd first like to see the bolts in use though.

[@boltonky]

Appreciate the video one of the best ones on how to do it, if only mx5 stuff wasn't so expensive where i live. Agreed custom work cost as its all about the time it takes

[@DougsShed]

Lots of other differentials which can be converted in similar ways. Just about every small front wheel drive car has a differential which can be converted.

[@gerarddavid9732]

Really nice explanation off everything I love looking at you video

[@DougsShed]

I appreciate that!

[@ilovebuhbbles2308]

Im so glad I came across this because Im gonna build a crosskart this summer and having no diff kinda sucks

[@DougsShed]

You may wish to use an limited-slip type differential if you are using your crosskart on dirt/sand/mud. Probably best to look for a plate and ramp type rather than a Torsen or ATB.

[@davidf.8497]

Great work! Thanks!

[@DougsShed]

Glad you liked it!

[@RUSTICW0LF]

That was great mate, thanks for sharing. Off to the scrappy now. 👍🐺👍

[@DougsShed]

Glad you enjoyed it

[@JA-dk3xc]

2 SAY THAT THIS IS GENIOUS... ITS AN UNDER STATEMENT 4 SURE.. THANKU 4 ALL UR EFFERTS .. 2 CREATE .. SUCH A WELL THOUGHT OUT VID.. EVEN I GOT IT..

[@DougsShed]

Thank you for your kind comments.

[@RDAUGIRD]

I considered a jackshaft, but it will be easier to just machine a spacer and put the sprocket in line with the trans sprocket. Thanks again for the great video and information.

[@lenny0347]

glad i seen this, cheers mate

[@DougsShed]

Thanks, hope it was useful.

[@paulpvhl1930]

Very generous. I'll subscribe knowing nothing of your channel. Thanks.

[@DougsShed]

Thank you!

[@13699111]

Thank you for posting this video I've been looking at trike conversion bad left leg I'm shocked at cost guess that says my age is old .

[@sonex413]

Beautiful! Subscribed!

[@DougsShed]

Thanks for the sub!

[@sonex413]

@@DougsShed You're welcome! Nothing better than watching this kind of creativity. I was a factory trained master tech at a Yamaha/ Kawasaki dealership for about 20 yrs, worked on a lot of custom and performance stuff. I appreciate the idea of taking what you've got and turning it into what you need! Not in need of a diff at the moment, but that unit sure is sweet! -Mike

[@psyborg9915]

Spot on info,sir,cheers!

[@DougsShed]

Glad to help

[@2000freefuel]

Awesome, now show us how to make a differential for the bottom bracket crank set!

[@FilterYT]

Very generous of you, thank you!

[@beastman.330]

Absolutely beuautiful work.

[@DougsShed]

Thanks

[@chrissmith7669]

Very nice video. Thanks for the excellent idea.

[@DougsShed]

You are welcome!

[@ethanwelch6345]

What kind of bearings and output shafts did you get? Or where? Really great video you even explained how much grease to use - thanks for making this

[@DougsShed]

I have used housed, self aligning bearings which combine the bearings with circular flanged, pressed steel housings SBPF207 for differentials with 35mm bearing spigots or SBPF208 for differentials with 40mm bearing spigots. The output flanged, stub shafts come with the MX5 differentials. The ones on the 1.6L MX5 have (4)10mm bolts on a 100mm pcd for MX5 bolt-on CV joints. The ones on the 1.8L MX5 have (4) 10mm bolts on a 110mm pcd for bolt-on MX5 CV joints.

[@chrislachance6304]

I really live what you’ve done here. Great idea and completely useful. I am looking to build a buggy for my daughter to cruise around my lake property and I’d like to make a 4WD for her and this is perfect but I need two haha. Could you tell me where you sourced the bearings. I’m living in Ecuador so I will likely need to source parts in the US.

[@DougsShed]

Have a look on ebay.com for US suppliers Found this one SBPF207-35 35mm housed bearings ebay item 282068285209 40mm version for the larger MX5 units should also be available with the pressed steel flanges SBPF208-40, or failing that the cast iron flanged housed bearings or pillow block type are usually available.

[@hakunamatataadventurebus5944]

Nice job!

[@DougsShed]

Thank you!

[@larrysullivan6536]

I absolutely brilliant I’d like to no the best way to mount that into a trike frame though if possible ?? Cheers great video larrysullivan in London

[@DougsShed]

Have a look at www.casarva.co.uk. They manufacture mounting frame and suspension kits.

[@MindField_Custom]

Doug, Absolutely amazing ingenuity. I do have a question. How much difference is there between the width of the original LSD and your chain driven LSD? Does the track width change much, or at all? I’m working on a design for a trike and I’m hoping to use something like this setup.

[@DougsShed]

The width between the output flanges of the differential is the same as the original Miata/MX5/Eunos. However, the position of chain sprocket may require the differential to be offset from the car's centre line, which would require different length drive shafts. If the bike engine can be offset or a jack-shaft can be used, you could fit the differential such that equal length (stock) drive shafts can be used.

[@larrylamb3480]

And to think that dealers are selling motorcycle differentials for trikes for THOUSANDS OF DOLLARS !!!!! Thank you sir !!!!

[@livinlikelarry8782]

Eyyy brother from another mother larrylivinlife

[@White_Night_Demon]

well first you need to go find a working diff for free for all this to work....

[@RDAUGIRD]

I am building a Harley Davidson Shovelhead powered trike, this will save me a bundle. The only thing I need to add would be inboard brake rotors on the stub axles. The trike is an old-school chopper that will have no fenders and I don't want modern rotors visible at the wheels.

[@bigdogbigben]

wow that awesome

[@forwardmotionrobotics]

Awesome videos on this Doug! Have you had any issues with these assemblies when pushed around 300hp? I'm building something similar with a turbo hayabusa and am looking at honda lsd units as well. Maybe larger input shafts and axles would be needed?

[@DougsShed]

At those power levels - chains start to be a problem. Twin chains and sprockets are sometimes used. After-market LSDs are usually pretty strong and you should look at ones with substantial (standard) output shafts. Possibly BMW. A lot of lightweight single seater hillclimb cars with tuned Busa power still just use Quaife QDF7ZR sealed chain drive ATB LSDs and standard tripod type (Ford Fiesta) push-in CV joints.

[@forwardmotionrobotics]

@@DougsShed Thanks for the info I'm looking into all of the above:)

[@annybodykila]

nice, thank you

[@M.TTT.]

Awesome, hopefully will use something like this in a future build. Cheers

[@DougsShed]

Go for it!

[@BEYTEK]

good to see another scottish youtube channel

[@DougsShed]

Thanks!

[@martingardener90]

Very similar to one I built a while back for a trike using Sierra diff parts. I had to get some machining done but nothing too expensive. I initially was going to mount a disc on the end of the can for parking brake but changed it to using the can as a band brake, now wish I'd stuck with the disc set up. Also was going to mount two sprockets - one for electric driven reverse but things were getting too complicated!

[@DougsShed]

Yes they can get complicated. I have built versions with single discs, twin discs and various types of electric reverse.

[@MikeJones-js8gh]

Great. Video . Thanks. One question. Where can you mount a brake disk. Thanks again

[@DougsShed]

With a chain drive differential, you can mount disc rotors on both of the flanged output shafts (sandwiched between the flange and the bolt-on CV joint). On LSDs and 'spool' units you can fit a single disc rotor on the body of the diff housing but this needs an additional machined mount/spacer for the disc.

[@SWINGERINTO]

Thank you, very informative! Is there any reason that this would work differently with a limited slip diff?

[@DougsShed]

I have made many chain drive differentials using lots of different types of limited-slip differentials. The Mazda MX5 Mk1 VLSD (Viscous Coupled LSD) is one of the easiest to convert. The MX5 Torsen type1 and type2 LSDs can also be converted however the housings have quite a few holes to seal up which can be tricky. The MX5 Blackline ATB LSD (as sold by Rally Design) is an excellent base for building a chain drive LSD.

[@SWINGERINTO]

@@DougsShed Thank you! I'm at the parts collection phase, and just recently acquired a 99 miata diff. Great video!!!

[@user-px8un6md9e]

Hello mate I've bought a Piaggio Ape Proto from Italy, (its an ape 50 converted with Kawasaki Ninja 650 engine) It was used to race on the snow but I'm needing to convert it to road use and looking for an LSD. Do you sell these diffs? thanks

[@polski7267]

Following this for a 1.8 diff now, Where do you get your alloy tube from usually? I’m struggling to find something that’s 108mm Guide is spot on though glad I found your channel I’ve watched a few now

[@DougsShed]

4.1/2" x 10swg (114.3 x3.2mm) www.ebay.co.uk/itm/ALUMINIUM-ROUND-TUBE-3-3-1-4-3-1-2-4-4-1-2-5-6-inch-select-size-length/192449775545?var=492464022926&hash=item2ccee687b9:g:3gUAAOSw0F9bm81a

[@SLfamily1]

Good job men

[@DougsShed]

Thanks!

[@coolhandluke1503]

Dear sir, in your humble opinion would an open center diff like this be impractical in a off road buggy/crosskart with a zx9r motor?

[@DougsShed]

Don't fit a differential to a crosskart - regulations usually do not allow differentials and they will detract from the performance & handling of the vehicle.

[@coolhandluke1503]

@@DougsShed I'm building a piranha from edge performance and the plans I have don't meet race spec, so I wont compete in this one. Not to worried about power loss as the zx9r is a bit overkill, was looking for a 600, but this is what came up in my local area. When you say detract from handling is that because of the single wheel spin making life hard on every type of lose surface? The idea behind the diff was to negate every buggy I've driven Achilles heel, poor turning circle, my plan was to create a cheaper open diff and if all goes well, then I replace it with a helical gear LSD, not even sure if this is viable, I would have to be sure the lsd would even work with the weight and power of buggy. Any advice is appreciated and thank for taking the time to respond

[@DougsShed]

@@coolhandluke1503 If you are set on using a differential, a viscous coupled type LSD would probably be the best as it gives good slow speed turning as well as reasonable grip on loose surfaces. I would not use a helical geared ATB as these can have very poor traction on slippy surfaces or when a wheel is off the ground. A plate and ramp LSD would give best traction but these can also induce understeer and larger turning circles at low speed (they are also high maintenance). I have used the Mazda MX5 viscous LSDs in many of my chain drive units

[@jhonatanzegarra2670]

I would like to know if this differential would be suitable for a 150 - 200 cc engine. that move from 1 to 4 people, or it would be too heavy that it would lose energy. excellent video, a very clean job, greetings from Peru! answer please!

[@DougsShed]

The smaller differential from the Mazda Miata 1.6 may be better for your small car. Many other small car differentials can be converted to chain drive in a similar way if Miata differentials are not available in Peru.

[@bodge7255]

Hi Doug. First of all I doff my hat to you. This is awesome. I'm mechanically minded myself i love this. Am i right in saying this could be made with pretty much any diff front or rear ?

[@DougsShed]

Yes, I have used many different differentials from cars such as the Ford Sierra (rear diff), Ford Fiesta/Escort/Focus (front diffs), VW Golf (front diff) and BMW (rear diff).

[@RDAUGIRD]

My 1.8 diff and stub axles came yesterday, excited to get started on this project. Do you know of any brake rotors that will fit the output shafts? I believe they are 4x110MM.

[@DougsShed]

Hi Richard, I think I repied to this question a couple of weeks ago. Anyhow - try these Suzuki GSX600f (89-97) rear disc rotors should be easy to adapt to suit the 1.8L. You would need to redrill to 110mm pcd. Rotors are 250mm diameter. These ones look like they have enough metal to redrill at 45 degrees to the original mounting holes www.ebay.co.uk/itm/203832938196

[@johnbowen2963]

wow im impressed

[@DougsShed]

Thanks.

[@JodBronson]

Awesome !!!

[@DougsShed]

Thank you! Cheers!

[@Hermanimace]

Hi, I really appreciate you sharing this information with us. I would like to ask what differential he would recommend for a kartcross buggy. It has 10´´ wheels and the working angle is small, but I drive with it on the road and gravel. Now I have no differential there. If you look at my videos, you will understand what I need it for. It is very understeer in sharp corners, but sometimes I need to drift. Thank you very much. (Sorry for my english, I am form Czechia :) )

[@DougsShed]

The Mk1 MX5 (NA) Viscous Coupled LSD (VLSD) would be a good choice. It is small, lightweight and the viscous coupled lsd action gives a compromise of good traction and differential action on corners. Plate and ramp type LSDs give the best traction but can promote understeer (similar to a solid rear axle). Automatic Torque Biassing (ATB) differentials can loose traction on slippery surfaces/gravel/mud or if one drive wheel is off the ground.

[@Hermanimace]

​@@DougsShed OK, thank you very much :)

[@bloodredhornet2704]

Fantastic

[@DougsShed]

Thank you! Cheers!

[@KyiPyarLayKoChittal]

Thank you sir

[@DougsShed]

You are welcome!

[@truog2003brasilia]

very cool!👍

[@DougsShed]

Thanks! 👍

[@anthonybrown7959]

Thats awesome. How cheap. I know of folk paying 1200 for a full works diff. I know which way I will be going. Could you list the bearings/ caps and suppliers please. Looking forward to seeing what you post next.

[@DougsShed]

The bearing and sprocket details and suppliers are now listed in the video description below the video (click "Show more..) to see all the text.

[@kmjquinlan]

So filling the diff up with grease acts like a limited slip? Or does it actually need to move and lubricate inside? Most greased bearings should have a lot lease than you'd expect, 10-20% fill to allow it to move around the bearings, when a bearing is packed full of grease it quickly overheats and destroys itself. Great job and great video, thanks for sharing!

[@DougsShed]

No - Grease filling will not create an LSD. We use LSD versions of the MX5 differentials, either the stock viscous coupled LSD, the Torsen Type 1 or type 2 or an aftermarket ATB LSD. The bearings are sealed and do not see the grease which fills the differential case. There are still some voids in the differential case which can allow for expansion. Heat build-up in the case is not as great as with a conventional differential as there are no crown-wheel and pinion gears (which are the primary cause of heat).

[@WilliamGuess-ns6th]

How are you supporting the axles outside, and are you just relying on the clips to hold the axles in?

[@DougsShed]

The clips hold in the output shafts (usually need extreme violence to get them back off). The CV type axles do not put any great axial loads on the output shafts.

[@yvesbouchard3519]

Just one word , wow , some people are really getting screwed... It was my project stopper, now it starts

[@DougsShed]

If you are making these for a living you have to charge a realistic price.

[@georgeclarke1183]

would this mazda 1.8 differential based conversion be able to handle the power of honda blackbird 1100 engine

[@DougsShed]

1.8L (up to 2005) differential is pretty strong and should cope with the power from a Blackbird. My choice would be the after-market, Blackline HLF030 torque biassing LSD - This unit is relatively cheap and easy to seal up and is compatible with the 1.8L (up to 2005) model's CV joints or output shafts. Available from Rally Design www.rallydesign.co.uk/product_info.php?cPath=885_2937_2975&products_id=24642

[@shaynegadsden]

It would easily handle it the mazda 1.8 has double the torque of a blackbird

[@Cbegnaud]

Genius!

[@DougsShed]

I love to re-purpose items.

[@homeshiphometv8168]

Great !

[@dkryptonut]

There seem to be a lot of RX8 bits around lately, do you think an RX8 diff would be a suitable substitute for the MX-5 diff?

[@DougsShed]

I did convert one RX8 differential for a customer. The standard RX8 differential was a Tochigi Fuji type LSD and was not easy to convert and the taper rings for the cone clutches were cracked and broken (very common) and the parts were not available to rebuild.

[@dkryptonut]

@@DougsShed ha, thanks, I'll avoid them then 🤣

[@bokicar1]

Dear Sir, do you have a recommendation where to find a sprocket to fit those bolt circuit? If I'm not mistaking it's 5 1/4 inch, which Is strange that is in imperial measures for a Japanese manufacturer.

[@DougsShed]

The bolt circle diameters of these sprockets are exact metric sizes. The sprockets were custom drilled to suit the Mazda differentials. I sometimes buy blank sprockets and bore the centre hole and drill the bolt fixing holes and sometimes I buy in completed sprockets from B & C Express www.bandcexpress.co.uk

[@bokicar1]

@@DougsShed Many thanks for your help

[@stevewhitesell4195]

Great video! Could you by chance tell me the the width, bearing shoulder to bearing shoulder, on a 1.8 miata diff? I'm building a small dune buggy, waiting on parts, antsy to get frame welded up.

[@DougsShed]

On the 1.8 Miata open differential fitted with the self-aligning, side mount bearings, the distance between the outer faces of the bearing mounting flanges is approximately 175mm.

[@stevewhitesell4195]

@@DougsShed Thank you so much. I'm looking at rebuilding a miata Tochigi Fuji Super LSD with broken tabs on the friction cones. Unable to find parts so may be tig welding new tabs on.

[@DougsShed]

That is a common problem with Fuji LSDs. Like you I could not find replacement friction cones for an RX8 Fuji LSD. The diff still worked with the cracked frictions in place (minus one of the broken off tabs).

[@keospinproductions]

could any diff work? essentially

[@nigelwood5127]

ha much for you to make me one your video was the best on this thanks

[@DougsShed]

Sorry, you will have to build one yourself - they don't get much simpler than this one.

[@paultelford3312]

Hi Doug - very instructive video. A couple of things I didn't understand about bearing fitment due to the length of the inner race of the bearings however: 1) when you fit the bearings onto the diff spigot at 16.40, the centre line of the balls within the bearing are not actually over the spigot section of the diff, does that not introduce a lever effect which will tend unseat the bearing? 2) because of the length of the inner race (compared to the original bearing which would be fitted within the gearbox) does that not prevent the CV joint splines fully engaging in the diff?

[@DougsShed]

Hi Paul, Thanks for your questions. The housed bearings do have long inner races but they are quite substantial and are fully engaged and locked to the spigots on the differential housing. The bearing placement will add a bit of leverage but this should not cause any problems. The projection of the bearing beyond the end of the differential spigots is not a problem with the CV joints as the MX5 CV joints have very long shafts as the original differential cases had oil seals placed well outboard of the differential. Have a look at my latest video showing how I fitted oil seal carriers to this MX5 chain drive differential. kzbin.info/www/bejne/i5Oco6Ogqtl1hJI

[@paultelford3312]

Hi Doug, I am actually making a diff carrier for a Sylva Riot which uses Fiesta shafts into a quaife ATB. It appears that the short length of Fiesta shaft may present a problem using the original Riot triangular diff carrier (and the bearings which i can't find the spec of) but I'm unable to find any information on them. Can you help? www.bing.com/images/search?view=detailV2&ccid=AXpjQIfm&id=7CE2D47EAAB5421BCB9AC0BB2A7F1D90D276E6AE&thid=OIP.AXpjQIfm3doSE36SrRqv0gHaFj&mediaurl=https%3a%2f%2fth.bing.com%2fth%2fid%2fR017a634087e6ddda12137e92ad1aafd2%3frik%3druZ20pAdfyq7wA%26riu%3dhttp%253a%252f%252fwww.scottmakin.co.uk%252fMy_Riot_0486.jpg%26ehk%3dyBnfpPXpWpxJFR2ic2FEVwpCNC4ugJKhEhuAqFSz2%252bc%253d%26risl%3d%26pid%3dImgRaw&exph=768&expw=1024&q=sylva+riot&simid=607987538931644663&ck=2017686A4919076C19ED9DDF67BB7E59&selectedIndex=391&FORM=IRPRST&ajaxhist=0

[@DougsShed]

Bearings will probably be these simplybearings.co.uk/shop/p23126/SAPF208-24-Round-4-Bolt-Pressed-Steel-Bearing-Housing-with-1-1/2-inch-Collar-Insert/product_info.html

[@paultelford3312]

those are 43mm wide on the inner race compared to the (non-self aligning) bearings which are specified by Quaife at 3/4 inch (=additional 24mm) . does this additional 24mm not preclude the CV joint's spline from engaging sufficiently in the diff for its C clip to locate properly? also, the ground shaft of the CV (between the body and the spline) is 28mm compared to the bearing at 1 1/2 inch so the bearing inner race will not be supporting it

[@DougsShed]

Hi Paul, IB5 Ford differentials have bearing spigots in the range 22 to 25mm long depending on model. Quaife QDF7ZR (Sealed chain drive differential) has a built in spacer on the left hand spigot which makes it shorter. QDF7Z (Standard IB5 ATB) unit has the longer spigot without the spacer. The 1/-1/2" ID housed bearing would need to have part of the protruding inner race machined off to set the outer face of the bearing flush with the differential's bearing spigot. In which case the housed bearing needs to be a good press fit onto the spigot as the grub screws could no longer be used. The bearings never support the CV joint, the 28mm stub shaft is a running clearance in the differential housing. With the MX5 differential, the CV joints have very long stub shafts therefore the housed bearings protruding beyond the differential spigots is not a problem. The other alternative is to machine purpose built bearing carriers and use LJ1-1/22RS sealed roller bearings. The purpose made bearing carriers could also incorporate 40mm ID oil seals for the CV joints. Doug.