Marui Samurai - Another SilverTriple's journey...

[silvertriple 2854]

Hi everyone,

Recently a project I had in mind materialised... The Marui Samurai 4WD was one of my dreamt cars when I was 15 years old. I never got one back in the time. This car looked awesome and aggressive. It maybe the most beautiful roll cage buggy of those times, ahead of the Javelin (which is still very nice and totally among my favorites).

For the technical specs : 

• 4WD
• 3 Differentials
• Chain transmission
• 1070g !

And what is really awesome is its look. It really looks aggressive, with bigger diameter rims and low profile tyres on the front, and some smaller rims and bigger tires at the rear end. And the driver figure is much more realistic than what it was on Marui's Hunter and Galaxy...

Few press articles I found out while searching for information (not exhaustive list - I'm still searching for more)

• Marui Samurai Test track - Radio Control Model Cars - March 1986 : https://www.overrc.com/vintage/documentation/archives-de-mike/Marui Samurai MC.pdf (source: www. overrc.com)
• Marui Samurai - Radio Race Car International - April 1986 : https://www.overrc.com/vintage/documentation/archives-de-mike/Marui Samurai.pdf (source: www. overrc.com)
• Marui Samurai Track test - Radio Control Model Cars -  July 1986 : https://www.overrc.com/vintage/documentation/archives-de-mike/Mauri Samurai MC Track Test.pdf (source: www.overrc.com)
• The Samurai 4WD (french) - Auto RCM - February 1986 : https://www.retromodelisme.com/article_page/1589/samurai-4wd-marui.html (source : retromodelisme.com)
• Marui Samurai Banzai! (french) - Auto 8 - February 1986 : https://www.retromodelisme.com/article_page/4227/essai-samourai-marui-marui.html (source : retromodelisme.com)[/list]

Long story short, searches were active on "Marui" in many places for ages before even I started my Hunter project. And I saw some Samurai going thru... Until I decided it was time...

• Few weeks ago, I contacted someone in the region where I was born and where my parents are still living. For the small story, the guy posted some pics of his Samurai on a group asking question on a car he was considering as he'd like to be able to use it without the fear of breaking something, and that was the day of my 50's anniversary... We discussed and it appear thru the discussion that the guy knew my uncle, and he accepted to book the car for me for a few months. I asked my father to go and buy the car for me, but was not sure how long it would take for him to do...
• Decided it was time to find some parts for a project, found one set of rear plates for almost nothing and ordered them, intension was to tease about the car on some forums
• A Marui chassis is always a thing to bother about when you start a Marui project. Dadio was selling one of his modeled chassis on ebay, he gave me the link and I was alone to bid on it.
• The day I received the chassis, one good friend in another forum contacted me to proposed me a Samurai with a broken chassis, as he knew that I was that in mind. Having a chassis already, I thought the chassis was made for this one, so I decided to go for it

The first of the two Samurai arrived home last week, with a Galaxy roll cage and few parts.

It's not complete, but I don't mind. This is a project, a new journey, and will keep me busy for some time, which is definitely what I'm looking for :-D

Yesterday, after getting the Nichimo Spirit FF down to parts, I decided it was time to do the same with the Samurai to have a more precise idea of what was needed for it.

Status at the end of what is missing or need rework :

• Left and right chassis to replace (Thanks Dadio to the rescue)
• Middle Front Bulkhead broken
• Gearbox damaged with a lot of play for the center diff (I believe the car was probably running forward in RWD and backward in FWD :-D)
• Rear right arm slightly damage where the pivot ball is placed. Luckily, it seems that I can just inverse the arms to get that back to work[
• One of the front Knuckle is damaged (again a thread which was damaged)
• Missing a roof, and roll cage requires work
• Driver missing

On the good side : not everything is bad, and with the play on the gearbox, I feel very lucky having none of the gears to replace...

And there is also the second Samurai I'll probably not have in hands before Xmas. In any case, this is one of the new background routing I'll regularly post about in the next few weeks/months...

That's all for today!

[KEV THE REV 2248]

You have actually found some of the weaknesses I spoke about , but luckily your gears are good . The diffs are like hens teeth to find . I had 2 of these , but they are long gone . As you said the Samurai is one of the coolest looking buggies ever

[silvertriple 2854]

54 minutes ago, KEV THE REV said:

You have actually found some of the weaknesses I spoke about , but luckily yours are good . The diffs are like hens teeth to find . I had 2 of these , but they are long gone . As you said the Samurai is one of the coolest looking buggies ever

Well, The Samurai Warrior was the coolest looking Marui car, but all Marui cars were cool, and very often cooler than their counterparts on the market...

[silvertriple 2854]

Ball bearing size is today's question...

The Marui manual is not really explicit regarding the ball bearing size (and some may be quite specific). So if anyone can route me to the proper size information, it would be very helpful...

Thanks

[CoolHands 636]

For the ninja I used 14 of the top one and 8 of the lower one. I suspect shogun would be similar numbers, and probably same sizes? The rs (rubber shielded) was for hubs ie exposed to the elements. I believe they only did 2 sizes ‘small’ and ‘large’ which is the 2 below.

4x8x3 (MS) Bearing (x1) MR84zz 

6x10x3 (RS) Bearing (x1) MR106rs 

[silvertriple 2854]

14 hours ago, CoolHands said:

For the ninja I used 14 of the top one and 8 of the lower one. I suspect shogun would be similar numbers, and probably same sizes? The rs (rubber shielded) was for hubs ie exposed to the elements. I believe they only did 2 sizes ‘small’ and ‘large’ which is the 2 below.

4x8x3 (MS) Bearing (x1) MR84zz 

6x10x3 (RS) Bearing (x1) MR106rs 

I went to the same conclusion. And in terms of numbers it's 10 for the 4x8x3 and 8 for the 6x10x3.

 

[KEV THE REV 2248]

21 hours ago, silvertriple said:

I went to the same conclusion. And in terms of numbers it's 10 for the 4x8x3 and 8 for the 6x10x3.

Just had a look through my parts list and I bought exactly those bearings and quantities some time ago .

[Goudar 526]

I grab a seat to see how it ends. Good luck !

[silvertriple 2854]

1 minute ago, Goudar said:

I grab a seat to see how it ends. Good luck !

I start to feel the pressure :-D

Not much progress this week-end. 2 days of work before the vacations, I hope to be able to have some progress (small) before xmas...

[silvertriple 2854]

As I  reached my parents place,

I finally succeed to get my hands on my second Samurai, which I had requested my father to catch up few weeks ago... It's in decent condition and I'm very happy with it...

[Ray_ve 747]

That's a beauty! Very decent condition. The perfect Xmas present.

[KEV THE REV 2248]

Awesome, with box and manual too

[Kol__ 2745]

I know next to nothing about the Marui range of cars, but that certainly is a cool looking car!

[silvertriple 2854]

Detailed inspection of the second Samurai without getting it down to parts for the moment (have enough in the queue to work out at this stage before starting this - and the first Samurai is still waiting for parts)... 

I took benefit of the weather to take some pics...

The driver is in, but he will require some work... I'll decide what I do with it once in parts : cleaning and rebuild or remove the paint, repaint and rebuild...

The roof mounting will require a slight revision... TX/RX are working.

The front body mount is broken and will require replacement (the STL is on thingiverse, that will make it)

The front damper is having a step when moving. I will check once down to parts and cleaned up (the one from the other Samurai is dirty but seems to work much better). The piano wires acting as spring for the front suspension may require replacement, as they can play a role in the step.

The chassis is marked by usage, but is in proper condition (no apparent sign of cracks)

The left half gearbox is damaged at the place where the motor support goes (the screw is in the Samurai box)...

Other elements :
- The linear MSC is in the box, and I don't know if it is working. I will have to test it. In any case, its fixation plate is absent (I may have it with the other samurai, which would allow to reproduce the part in 3D printing if needed).
- There is an ESC to run it (Hobbywing Quicrun 1060WP), and it is directly glued with tape on the accu pack
- The rims are marked, but I have seen other in much worse state. Tires are worn out. I will need to find a solution for those.
- Differentials are working perfectly. Small details, and I don't know if it is a question of settings or a problem, this will be seen once the gear box is tore down : the rear is driving front, but the front doesn't drive rear (I think it may be link with the center differential setting, but this will need check later on).

[silvertriple 2854]

The different sizes is a key particularity of the Samurai.

I'm trying to recap here the different options:

1. Original rims.
   1. You may search on Thingiverse, someone put some stl for the tires, printed in some flexible TPU filament, they may be a valid option...
   2. However,  I may have found a much better solution IMHO
      • Front : T693 | Block - Front Tyres - Blue - CAT (pr) | Schumacher RC Racing (racing-cars.com) - 2 inches, min block tires (same dimensions as the front Samurai tires)
      • Rear :  Rear Tire(Medium/2pcs/w/Inner/Scorpion2014）SCT002MB - KYOSHO RC - mini block tires, same dimension as the rear Samurai tires...
2. Other alternatives requires new rims or designs not too much different between front and rear.
   1. You may consider similar diameter tyres such as Hotshot tires, Alien8 sells Samurai like wheels for Hotshot tires (shapeways) - and it would be probably much better to get front and rear to get the same design
   2. Other solution is to use at the rear Kyosho Turbo Optima re-release wheel set (2 inches, large) and front from Kyosho 4wd Optima (jcracingproducts.co.uk) with tires from Kyosho (the front version for the one used on the Turbo Scorpion re-release which is used on the Kyosho Dirt Hog (2.2 inches, 4WD Front)...
   3. In last ressort, you may use any 4WD Hex Wheels with an adaptor (some exists on the Shapeways, and there might be even some on Thingiverse if you have the capability to print).

Obviously I prefer a combination that keep the particularity of the rims diameter difference which is key in the Samurai design.

Now that being said, you should also consider that the tires are participating to the dampening, and changing the size of the rear tire profile may lead to some damage to the shock towers... The best options is maybe the one using the original rims and tire sizes.

 

[KEV THE REV 2248]

Would the eBay Pargu Samurai rims help your research?

[silvertriple 2854]

10 hours ago, KEV THE REV said:

Would the eBay Pargu Samurai rims help your research?

Well, they are nice for sure... But expensive as well. It's on my watch list since I had a Samurai in mind... And with solutions they could make it... 

(link is here: VINTAGE MARUI Samurai Roues en alliage SET style ancien neuf | eBay)

[KEV THE REV 2248]

They are very nice . I have a set of his covers for my Rough Rider 

[silvertriple 2854]

On 1/22/2022 at 11:18 AM, KEV THE REV said:

They are very nice . I have a set of his covers for my Rough Rider 

Nice they are... But what about their weight? I'm said they are heavy, so not really suitable to run....

[silvertriple 2854]

Samurai wheels... They are beautiful, and I'd like to keep the unique design for it when running my Samurai with some more modern tyres. That means different dimensions...

Tried to think about my strategy... And thought about a parameterized wheel in Fusion360, with the target of being able to create different size of wheels by just amending the diameter and the width (and eventually to be considered later on the type of wheel driver)...

Started to set some parameters in Fusion 360, creating a profile, revolving it, and so on...

And tadaaaa

I've not tried yet the next step, which is to change the parameters... But, I have some hope

[silvertriple 2854]

The "wheel resizing" feature doesn't work as expected yet. Some parts are not resizable yet, and the slot are not expandable. I believe it is due to the filets, and I may have to think more to get it right, but I already progressed a lot on that aspect.

Went to bed far too late yesterday (this morning actually), and it was not solved, but at least, I had an idea during the night on what to to to make it work

[silvertriple 2854]

Milestone... (and thanks @optimaforever for the hints)

Good progress done on the wheel definition. I can modify the number of slots, the arms thickness, the internal diameter of the tire...
Next on this is to add functions to add some proportionality to the slot internal and external diameter, and eventually on the hub size, but the key principles are set. 

Next is to add rings to set the modern tires in place, and to apply the same principles on a rear wheel (and I did not have to redo the whole thing, just to tweak what I've done until now - for those trying to the do the same, extrude the slot without fillets, and apply fillets after that, it seems the fillet is not playing well with a parameterized circular pattern).

[silvertriple 2854]

Continuing digging into the parameterization of my front wheel, with the idea than the spoke thickness should  increase when the diameter of the wheel increase or reduce when the number of spoke is higher, and tried to add some parameters to do that.

It seems that confusion360 doesn't not like this, like the fillet, and move things even though it should not be affected by the calculation. I also noticed that you have to specify when creating a parameter it is a value without unit, even if you divide a distance by another as apparently, it doesn't consider it this way, and if you use this value to multiply a distance, it would trigger some error as you try to multiply millimeters with millimeters... I guess I touch the limitations of the parameterization... or it is just bugged.

Anyway, I will keep my wheel the way it is with 3 parameters to deal with to set it to another dimension or n-slot type, and I'll manage the spoke thickness by myself for the time being...

[silvertriple 2854]

Until I had to build this wheels with some(lot)thing(s) in mind, I was using Tinkercad just because it was much more easy to play with (but too limited, clearly, which means I already hit the limits of it in quite a few occasions). This is basically the second thing I designed with Fusion360 (the rear reinforcement from the Hunter was also made in Fusion360, but I did not really understood a lot of things). I started on Wednesday evenning this week on the wheel. Few hours later, I already did more complex things than what I ever did in Tinkercad. It's really powerful and it can do quite a lot of things... Between Wednesday and today I made a lot of mistakes, learned a lot of things, revert back other things, understood a lot more of things and so on... The basis to learn something...

Even found a way to make my wheel look like the real one

Then took the rear wheel out of the Samurai, and started to model it. It's not parameterized yet, but it's already in good path...

Once parameterized, I will be able to do something else :-). Maybe first will be to redo all my previous parts in Fusion360, again to learn new things, and maybe to even get them better than what they were initially with Tinkercad...

In the meantime, did not succeed to get the printer working again. I still have something that I do not understand: maybe my nozzle is partially cogged again and that could explain this. But it's very difficult to handle multiple things at the same time, specially while discussing with others on instant messenging at the same time (even if this sometimes helps :-) )

[silvertriple 2854]

Once you get the trick, it's surprisingly easy...

Make sure your apply all the required constraints. If you forget to apply linear axis colinearity with your first symmetry axis, it doesn't work with the circular pattern properly... In terms of wheels, I can already see some easy stuff to do