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

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@@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.

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Glad you liked it!

Glad I could help!

I have made a few of these before!

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Happy to help!

You're welcome!

Glad to help

Thank you! Cheers!

My pleasure!

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.

Thanks 👍

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

Thank you for your kind words.

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

You should!

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

No guts no glory.. Trying to put a shaft drive V Star 650 in mid size go-kart chain drive kart rear end/shaft drive street bike motor and transmission.. lol I have the need for speed 😂

Eyyy brother from another mother larrylivinlife

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

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.

You are very welcome!

Glad to help

Go for it!

@@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.

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Thanks for watching!

Glad you enjoyed it

Glad you enjoyed it!

Glad you liked it!

Thank you! Cheers!

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

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

@@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

@@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/

@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.

Sounds like a great idea.

@@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 RU-vid channel with a short video about it. U will send you a link when I make th video. Thanks brother.

Thanks for watching!

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.

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Thank you for your kind comments.

You are welcome!

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.

I appreciate that!

You're welcome!

Thanks.

Thank you!

Thanks, hope it was useful.

You are welcome!

Glad to help

Thank you!

Thanks for the sub!

@@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

Thanks

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

Thanks!

Thanks!

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

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

Go for it!

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.

Thanks.

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.

There may be an existing bike sprocket which could be modified to suit the differentials. Probably have to drill alternative holes in the sprocket and possibly open up the centre hole. Companies such as Talon can custom machine sprockets to suit. Alternatively, blank sprockets are available on eBay and you would need to get the centre hole and fixing holes drilled.

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.

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.

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

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.

Thank you! Cheers!

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.

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

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

Hi Richard, 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 The above rotors should fit the 1.6L NA/NB (100mm pcd) output flanges using the existing bolt holes in the rotors)

You are welcome!

Most differentials can be run in either direction. Open diffs, viscous coupled LSDs and ATBs run OK either way. Plate & Ramp clutched types can only rotate one way. An alternative to the chain line problem is to use a jack-shaft to move the chain to the position of the differential's sprocket. This allows you to use standard length axles from the differential.

Thanks! 👍

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.

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

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.

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

Yes, it does not get too hot as there are no hypoid gears constantly revolving. I did make a 3D printed oil/grease retaining cover for one differential. I painted it inside and out to make sure that it was oil resistant.

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

@@DougsShed Many thanks for your help

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.

@@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.

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).

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.

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

1.6 diff is 240mm and 1.8 diff is 278mm

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.

Thank you! Cheers!