Funco SRB Build (short rear track width)

[casethejoint]

I have been inspired recently by the awesome Funco Rough Rider based buggies by @ScaleXtreme :-

... and @TamTom and others here, and I've always fancied building one. So I have decided this is to be my next project

My issue with all those that I've seen so far is the rear track width. The original SRB is not very scale in this respect - it's far too wide. Makes for better handling of course, but to me it's never looked quite right.

So I decided to start with this problem to see if I could solve it. What I noticed is that there's a spacing bit of metal in the rear swing arms, that's about 10mm, and I think could be removed with a little black magic. So this is where I started, bye bye little 10mm piece of pot metal:-

... and mated back up again, looking something like this:-

Now, I know what you're thinking : "But Dean, the shocks won't clear the rear wheels!". I know, I had the same thought. But in the spirit of making it up as I go along I thought I'd proceed and see where I got to.

So I cleaned up the cuts with little filing to get a good face edge:-

I need to get some bulk and strength back into this piece, so I fabricated a collar from some alloy tubing:-

 

This fits like this:-

 

... and made a jig for myself with a vice and a piece of 6mm dowel to keep the hole clear and enable me to put it all together:-

Glue of choice for this type of thing for me is J B Weld, so I mixed some of that up, filled it into my fabricated collar and clamped it all together (the collar is a tight fit).

And it came out like this:-

Which will take about 10mm off each side of the track width.

Happy with that, so I proceed to put together a gearcase from some spares that I had (won't show you pics of that, you all know what an SRB gearcase looks like - nothing special here, no diff or anything, but I did ballrace it of course and also used some stainless screws).

I then built up the one shortened side that I'd built to see how it all hangs together:-

Looks pretty good.

Made some shortened drive shafts:-

... and popped a wheel on to check out how bad the shock problem is.

Now it gets interesting. Believe it or not, if I can mount it like this:-

... it just clears

So I think this is going to work! I have already planned to make some slightly narrower tires by cutting out a ring of tread and re-gluing (waiting for my flexible CA to be delivered) to get some scale looking tires. For that I'll have to shave off a couple of mm from the wheels and I think that will ultimately give me the track width that I'm after for this build.

So I finished off the other side and here's where I'm up to, now waiting on the JB Weld to cure.

 

 

[mongoose1983]

Brilliant! Now I'm curious and would like to see how that looks under the Sand Scorcher bodyshell. Any chance, Dean?

[SRB Bloke]

Brilliant work, loving the concept and looking forward to seeing more. 

[casethejoint]

I personally think it looks better Erich, as the SRB was always, from a scale point of view, too wide at the rear. I don't think that's limited to Scorcher and Rough Rider either, I think this will work better with all the SRB's (I'll try each of them).

Of course it will have a serious impact on the handling of the buggy in corners. And as we all know the SRB is famed for it's "on rails" handling so that's a shame

Stock SRB width:-

Width reduced:-

 

The shocks will definitely not work correctly with Scorcher wheels and tires. So for this I'm thinking the Superchamp rear suspension might be better. I can't see a simple way to reposition the stock shocks.

Sorry for lack of side on pics but the body isn't mounted properly due to wrong rollbar being fitted. I'll dig out the correct one and post some more pics later....

@SRB Bloke - thanks. I might need to pick your brains on tire width reduction, for which I know you're the resident expert. Specifically, do I run glue all around the cut and put it together in one hit, or do I do a centimeter or so of glue and work my way around piecemeal? Also, should re-enforce from the inside once done? I have some old Ford Ranger tires ready to experiment with, although the glue hasn't arrived yet.

Thanks!

 

[Shodog]

Great work on that rear arm. I would caution you on running it. In stock form the car is not wide enough and will roll with the slightest provocation. This mod will make it roll even easier. 

[casethejoint]

@Shodog - indeed. The only way this thing is ever getting around a corner is if I can find some 6" gauge railway track, but that's a whole other project for another day

[Backlash]

Have you considered designing some narrow rear arms and getting them 3D printed at Shapeways??  That way you could also move the shock mounting point in to clear the tyres..

If you cant do it yourself, then maybe someone like Toykid or Pintopower can help you with the design side of things..

I noticed on Pintopowers recent SRB/Hornet hybrid build that he made some narrow rear wheels to narrow the track of that buggy.. Maybe some narrow rear SRB arms would be another way to get around that problem as well..

https://www.tamiyaclub.com/showroom_model.asp?cid=130770&id=26101

[casethejoint]

Found the right rollbar, so here's a few more as a Scorcher Erich. I think it's good - more scale?

 

@Backlash - yes, actually there's lots I'd like to do at Shapeways :). For rapid prototyping though for me I still quite like a hacksaw and a few other metalworking tools. There's a lot of time you have to invest in 3D printing on the modelling side, getting the dimensions right, print/test/tweak cycles etc. Takes weeks, whereas this all took me maybe 2 hours. And I got to use a saw, which isn't that often in Tamiya land :).

 

 

 

[mongoose1983]

I absolutely LOVE the looks your BajaVW got with the mod!  

[SRB Bloke]

Maybe it would be a pain to drive, but you're right that scorcher looks a lot more scale..

No probs on those tyres, any advice you need just pm me...   I always reinforced the joint with the piece of tyre I'd cut out  (after I'd dremelled it in to a flat piece of rubber..  I used black flexible super glue and normally did it a few centimetres at a time as I went round the tyre.  

If you get really stuck let me know, I've made a few different ones for different people who where building Funco's most famously @Sayroll

keep putting up your pics, really liking this thread.. 

[casethejoint]

Thanks @SRB Bloke I may need to take you up on that, but I'll have a go first

Right, Scorcher pics out of the way I disassembled it all and got the new rear arms ready for the barrel polisher (basically had to dremmel polish the bits that I know the polisher will miss):-

... and in they go, where they'll stay a couple of days and should come out nice and clean together with some mucho shiny UJs.

Meanwhile, back in the garage it's gonna get messy:-

To be continued...

[Grastens]

If the modified shell is going to be as cleanly-executed as those rear suspension arms, it should be quick and relatively pain-free for the hapless shell 

[njmlondon]

Loving this project!

what is that barrel polisher? Never seen one of them.

[casethejoint]

I managed to get the sides off today and have filled one side with some 1mm styrene sheet. Will do the other side later in the week.

Next I need to make a horizontal line across the sides in order to get the right alignment of the side cheeks. They need to be a little lower than the Rough Rider, and the driver also needs to drop. @ScaleXtremes thread is proving very useful for ideas.

Anyway, I don't think I can start to work out my horizontal line before getting a chassis together to put this on. I thought about using my Rough Rider chassis as a guide, but with the narrowed rear track and the fact that I'll also be reducing the rear camber a little for this Funco build, I realise I can't proceed now without finishing the chassis first so I can put the body on and work out those final lines. 

So I have to await the barrel polisher and might go quiet on you all for a week.

@njmlondon - 

 

[SRB Bloke]

Quiet for a week !!!!! Nooooooooo! How will we cope without another update.  I'll just have to go and watch paint dry. 😩

[njmlondon]

On 5/7/2017 at 10:23 PM, casethejoint said:

I managed to get the sides off today and have filled one side with some 1mm styrene sheet. Will do the other side later in the week.

Looking good so far.

What is your build method for the side pods going to be? I have seen one done with shaped balsa acting as a former. Is this what you will be doing too?

[casethejoint]

Thanks - if you compare mine to @ScaleXtreme you'll see his cuts are much better (amazing in fact, it's not easy) than mine.

Since this pic I've filled it and once primed and painted it won't make any difference. That said I'm using this project as a way to hone my styrene chops a bit. I've used it a little in the past but mostly for repairs to shells. This is my first full on conversion.

So will be styrene all the way rather than balsa. I'll use the rib method to ensure both sides are equal and I'm going to heat form a styrene sheet to get the curves. That part is something I've never done before, so I've ordered, ahem "a few", styrene sheets so that I can make the odd mistake and not tell you/pretend it never happened

[SRB Bloke]

23 hours ago, casethejoint said:

So will be styrene all the way rather than balsa. I'll use the rib method to ensure both sides are equal and I'm going to heat form a styrene sheet to get the curves. That part is something I've never done before, so I've ordered, ahem "a few", styrene sheets so that I can make the odd mistake and not tell you/pretend it never happened

Don't stress its real easy stuff to work with....  when you want to make two side identical always make the former/templates at the same time, and remember to make any changes to both templates as you work forward.  I know that sounds obvious but its easy to forget/get carried away when working.

Have Fun !!  

[casethejoint]

Yep, I'm loving the material and ease to work with (and the PlasticWeld glue is great for speed to set and strength).

Thanks for the tips. I've also found some good videos on heat forming for the curves, which is the bit that I'm worried about as I've not really done anything like that before.

The great thing is other than the body cuts, I can't really go far wrong as it's non-destructive. I'll just have to throw away what doesn't work and try again. So perfect opportunity for me to learn a few tricks with the stuff.

[casethejoint]

Hi gang,

Apologies for the long delay in between posts. The usual family and work commitments have been in the way, but I finally managed to grab a few hours to make some progress on this build.

In truth, it's not all family and work. I'm on the edge of my capabilities with this one (which is great, nothing like pushing yourself  ) so there's probably an element of trepidation/lack of confidence. But a little bit of rare spare time and a couple of Peroni's have seen that put to one side tonight

So here's where we're at.

I put together the chassis because I need something to try and understand how the body sits in relation to the wheels etc. Prior to my last post I managed to get some bits into the polisher for a few days, so basically we have uber-shiny bling. I know that a lot of people here don't like 'em shiny, and I know it's not really very "scale" looking, but I'm a sucker for it so there you go :).

So this is my chassis.

 

 

Which at least gives me a good platform to start hacking the body into shape. This is where I got up to last time.

So, today, I started trying to work out where my line is on the side flares. This is my final placement, based on looking at a few real Funcos online and deciding that the rear line starts where the existing Tamiya molding has a protrusion just before the rear shocks.

... to my eye, that line should continue with the side flare so it becomes one line. This is about a 5mm drop from the original Tamiya RR shell.

Here's a side-on view showing how this sits with the reduced rear tracking and also my sliced up reduced width Sand Blasters (which didn't come out great - more on that later).

These rear wheels I think are perfect btw - they came from Chris at Rogue, but I seem to have a set suitable for a Ranger and not a narrow front pair. Will email him tonight just on the off-chance if he has a set of narrows.

So, into the vice the side flares go :). This is the saw-eye view.

 

Speaking of saws, this is what I used. It's a Tamiya razor saw. I know Tamiya tools are expensive, but there really is nothing nicer than working with decent tools. And this really is a decent tool - made this so easy. And I also am a firm believer that exceptionally sharp tools are actually safer to work with.

This is the first (left side) flare after first cut.

And in situ, will be something like this.

I'll need to get this slope angle right - I think I have it pretty much bang on where I want it in this pic. Hopefully I'll be able to position it right when the time comes.

The inward curve is about the radius of a Halfords spray can lid, which was convenient

This was a rough cut

And then after a little dremeling, this is what I have

 

The rest of my evening was spent doing the other side, which I now have and a nicely matched pair (I used the left one as a template).

I have given a light coat of primer to the shell to show up any areas that need filling before I make the ribs and start to glue this together.

I hope to have some more time again pretty much every evening this week (yay!) and will post more progress pics as I go

 

 

[casethejoint]

Pretty good progress tonight. I made up the ribs using a vice to make sure all 4 were as close to equal as possible.

These then fit into the top of the cheeks that I cut out earlier. I just put a dab of glue to hold in these in position while I worked out where I was going from here.

Once I was confident I stuck these in properly and added some re-enforcement for strength.

I curved the sides of the cheeks using a hot air gun and then bending by hand. This part was really hard and took most of the evening - there were a few failed attempts before I got something I was happy enough with. And it's not perfect. But I learned a lot about doing this and I think next time I could do it better.

Glued and clamped to get into position.

I've filed off the edge here so that the front curve piece should sit nicely.

This is what it'll look like in situ.

Some filler and a rub down later.

 

I'll leave these overnight then give them a coat of primer to highlight any low spots that need more filler. Then I have to take the plunge and stick 'em on

 

[casethejoint]

I filled and sanded the side cheeks into shape, then took the plunge and attached the first side.

 

As you can see, here I've rough cut the front curve piece. I used some thin (0.5mm) styrene for this - no way are my heat bending skills up to scratch to do a fiddly piece like this that way.

Here it is after a little sanding.

 

I then started to fill it ready for final sanding before hitting the other side.

 

The garage needs to make way for some household DIY things now so probably won't get to side 2 until tomorrow.

After both cheeks are on I'm planning to do some tweaks to the rear which have come to mind since I started this - more on that later

[casethejoint]

Got the DIY homework out the way faster than expected, so was able to do the other side

If you look closely it's the *tiniest* bit out of symmetrical, but honestly I'm dead chuffed with how close I've got it and there's no way I could have done better than this. Totally at the edge of my ability. Very happy

More filler and glue than bodyshell now

Right, here's where I am with the rear..... get where I'm going with it? Any guesses as to what decal is going over this?

I've since removed this attempt and need a slightly larger radius (it just fouls the shock mount) but I'm convinced it's the path forward.

[SRB Bloke]

Looking good, don't let the thought of it put you off. You're doing well, the more you do the easier it gets and you'll learn your own techniques..

The same with the tyres, if it's re-joining the tyres back together that you're not happy about there are ways of making that easier..  keen to see how you've got on.

keep those updates coming.

[casethejoint]

Thanks Steve - yes it is getting easier, and I'm definitely building some chops too. So all good. I have actually exceeded my own expectations so I'm not complaining. Also, the bits that I was dreading (those side cheeks) are now done, so downhill from here for me.

The tires - not great. I won't show you my first attempt. And I probably won't show you my second attempt either. Not sure if there'll be a third and I might have to drop you a line about that ;). I think I'm good with things that don't move around too much on you. With metal and styrene I can put it in vice, rig up clamps, all sorts of ways to hold and manipulate things. Rubber I'm finding is very unforgiving that way and so not something I naturally have any kind of technique for.