Graupner/Mugen Mercury CAD model...

[terry.sc]

Our vintage races have strict official 1/10 buggy dimension rules, after someone turned up with an Optima about 60cm long. So the Mercury has to stay under 250mm wide and there isn't much room there if you want to change the wheels. The hubs are JC Racing Products 2.5mm Yokomo wheel adapters with JC Racing YZ10 wheels.
The adapters are made for a 5mm axle so I sleeved them inside with 4-5mm aluminium tube. It does mean you have be careful to keep everything square when assembling as it is easy for the hub to be slightly off centre. The ends of the adapters still made it wider than 250mm so they were ground back to flush with the end of the axle using sanding drum in a Dremel. My first plan was to get some adapters made with a 4mm hole but I couldn't get them done on time.

I have my doubts as well, looking at how thin the material is right there : the ball bearing installed inside the small gear makes the material is quite thin there, giving it no chance to survive, and I'm doubtfull on the possibility to 3D print it in metal...

I am looking at replacing the centre differential gear as well and trying to work out if I can make the differential gear smaller so the smaller gear could be larger for more strenght around the bearing and to give a better gear ratio for brushless motors, but I don't think there is much space in the differential gear because of the pins for the small gears. Ideally moving the pin the spur gear runs on downwards would allow a bigger gear for more strength, but it would mean the gear cover no longer fitting.

Something I've got to think about and work out a solution, as I don't expect to ever find a set of replacement gears.

[silvertriple]

Our vintage races have strict official 1/10 buggy dimension rules, after someone turned up with an Optima about 60cm long. So the Mercury has to stay under 250mm wide and there isn't much room there if you want to change the wheels. The hubs are JC Racing Products 2.5mm Yokomo wheel adapters with JC Racing YZ10 wheels.
The adapters are made for a 5mm axle so I sleeved them inside with 4-5mm aluminium tube. It does mean you have be careful to keep everything square when assembling as it is easy for the hub to be slightly off centre. The ends of the adapters still made it wider than 250mm so they were ground back to flush with the end of the axle using sanding drum in a Dremel. My first plan was to get some adapters made with a 4mm hole but I couldn't get them done on time.

I have my doubts as well, looking at how thin the material is right there : the ball bearing installed inside the small gear makes the material is quite thin there, giving it no chance to survive, and I'm doubtfull on the possibility to 3D print it in metal...

I am looking at replacing the centre differential gear as well and trying to work out if I can make the differential gear smaller so the smaller gear could be larger for more strenght around the bearing and to give a better gear ratio for brushless motors, but I don't think there is much space in the differential gear because of the pins for the small gears. Ideally moving the pin the spur gear runs on downwards would allow a bigger gear for more strength, but it would mean the gear cover no longer fitting.

Something I've got to think about and work out a solution, as I don't expect to ever find a set of replacement gears.

Only option I can think of is Aluminium for the spur gear, but with CNC... Costly, but probably the most solid option we can consider...

[silvertriple]

My Mugen Mercury chassis was damaged at the rear end. I found a NIP with the 2 chassis halves, and took it, and I will rebuild the car using it. The Mercury I had for some time is back in his owner hands.

The right spindle was broken on mine. And my friend had only left spindles. And while @GoMachV sent me a set with the right spindle, I gave the set to my friend as a contribution for given me the honnor to model the car. I printed spindles using Nylon-Like resin (Siraya Tech Blu Obsidian Black), and I have the intension to use them for this car, and to put them to the test.


I started to remove everything from the original chassis to put it on the new chassis.

The build starts by the motor plate and part of the center diff


Next you complete the center diff. I put the belts already, as the rear one could be difficult to push in after the center flanges of the center diff.


Next you complete the gearbox... Something to note : I don't think the spur gear will last long. I may need to find a solution. @terry.sc, please update on your own progress (i'm interested, as i'm likely to have the exact same issue soon).


Looking at the way the spur gear is, no fancy motor here. A plain old sliver can.


The gearbox cap is another new part...


Both front and rear diff and associated setting excentric rings are brand new as well.



I just noticed while mounting the right spindle on the right arm that I'm missing some of the bushings... I've ordered ball bearings to replace them... They will take a lot of time to come, but that should give me plenty of time to sort the rims/tires topic out : i'm not sure I'll change the axles, although that might be an option (I checked what I have here, and nothing fits perfectly, and while I have the information that i would work with some DF3 swinsghafts and axles, it would also require me to change the diff cups by something difficult to find nowadaysà...
Anyway, this build was started but is now on hold...

EDIT: I just ordered a SLS print in a special nylon for the spur gear. I'll report about this when parts arrive...

[terry.sc]

Next you complete the gearbox... Something to note : I don't think the spur gear will last long. I may need to find a solution. @terry.sc, please update on your own progress (i'm interested, as i'm likely to have the exact same issue soon).

EDIT: I just ordered a SLS print in a special nylon for the spur gear. I'll report about this when parts arrive...

I have only just this weekend had chance to look at cleaning them, a lot going on at home means I don't have much free time to do anything at the moment. I do want to get this sorted as it is nice to drive and want something durable. As soon as I can get something organised I will let you know now i know we need two sets of gears. I would be interested in knowing how the 3D printed one works out.

[silvertriple]

SLS Prints arrived today...


Only thing left is to test them... I really need to rebuild the car to move ahead on this part...
@terry.sc, you may contact me in pm if you want more details.

[silvertriple]

I have no proper wheels for this car... And although I have the model of the Mercury rims, I don't like them. Further the driver is 14mm axis with a very large axle...

I have few options :

• replace the universal and diff cups by something more recent to install a 12 mm hex (I'm said that original optima diff cups and DF03 universal would work for this)

• start with a 4mm bolt, cut it, and drill to holes to put a pins to lock the parts and implement a 12mm hex while keeping the original universal

• print specifically designed rims for the Mercury 4XI with the original 14mm hex drivers

Last option appears to be the quickest on my side, and looking at the way the hubs are on this car, it is likely that I would have to print rims anyway... I decided to design rims with the same offset as the original ones, and here is the design : it's a very simple one, and I did also design front rims a bit narrower, as the target is really to use very standard 4WD 2.2" tires...



I'll have to print the rims very soon...

[silvertriple]

The chassis assembly moved a bit... I used non branded shocks I found on Aliexpress and they seem to be of a good quality...



The rims are printed, but I want to review a small detail: the hex room a bit too tight...


Remains to do : RX and ESC implementation, then it will be time to deal with the custom bodyshell...

[terry.sc]

The wheels look good, The kit wheels are useless if you are going to run it anyway, the plastic under the chrome is hard and brittle, I have got a new set I picked up but they will just be used for display as one of them even shows sings of cracking in the packet.

start with a 4mm bolt, cut it, and drill to holes to put a pins to lock the parts and implement a 12mm hex while keeping the original universal

This was going to be my first plan, get some new axles made to fit the kit universals so I could use hex drives but 3 of the 4 screws in the universal joints were locked solid. Normally I would use heat on the screws to break down any threadlock, but didn't want to do that in case I damaged the plastic parts. That is why I resorted to Yokomo wheels and adapters as they were easy for me to find.

[silvertriple]

The chassis is now operational, and wheels are fitted on it. They are definitely better than the original rims...



Next is to trim the custom bodyshell...

[silvertriple]

Bodyshell and wings are trimed, and I can say that I'm very happy with the result...





I will have to do some paint next...

[silvertriple]

The Mercury 4Xi came with a key for the wheel nuts. They are bigger than what we found usually on 1/10 EP cars. And it's damaged.

I solved this with a very simple but effective print...



Next part is the paintjob. Something simple is on the card. I used some masking tape to try to define the windows format, and I will scan it and cut some masks from that... For anything else, the plan is to do something very simple...

[silvertriple]

Spent this morning to deal with the paintjob...
Fluorescent red, white stripe, black and smoke for the window. Quick reminder : this is not an original bodyshell, it is based on an approximative CAD model, mold was printed and the bodyshell was vacformed by a friend (I may have to work out a better bottom line for the mold, as it appeared difficult to read on the bodyshell, and you can see on the pictures the way I trimmed the body is far from perfect)...





The car is just missing body clips and it is be ready to run...

[Ambrose44]

As someone who raced a Mugen Mercury in the early 90’s let me say that what you have done is just incredible. I was heart broken when my first Mercury was clapped out. Some years back I acquired another one but haven’t yet completed the build (I’m a bit reluctant to run it because they are so rare).

Are you selling these in kit because I would be interested in purchasing one of you are?

[silvertriple]

As someone who raced a Mugen Mercury in the early 90’s let me say that what you have done is just incredible. I was heart broken when my first Mercury was clapped out. Some years back I acquired another one but haven’t yet completed the build (I’m a bit reluctant to run it because they are so rare).

Are you selling these in kit because I would be interested in purchasing one of you are?

At this stage, At the very exception of custom wheels, I have non of the parts validated with 3D printing test... It's a long way to go before I get there... And last comment : I do not sell kits or parts; I do files for 3D printing.
you may follow my page on https://www.facebook.com/profile.php?id=61555214226826 as I may get into the Mercury printing tests at some points, but it is likely to be a few months from now as I have already a lot of in progress project closer to concretisation phase....

[silvertriple]

One of the Australian vintage bashers contacted me as he would like to get some parts for his car. At the very exception of the spindles, wheels, and metal motor plate, I have not tested anything yet on this car.

My chassis should not be that far off based on what I can see with the bodyshell, but I'll have to test it anyway.

In the meantime, I decided to start dimensionnal testing on the arms and shock towers...


I've launched a print, we'll see how it looks like in comparison to the reality...