Original Terra Scorcher - Recommissioning

[Golden]

Hi All - I recently bought a Lunch Box Mini, and then a Monster Beetle.... and then got my folks to dig out my Terra Scorcher from 1988/9 ish... 

Just charged the original Tamiya battery packs and put EIGHT AAs into the controller with an antennae taller than the house.... and it works! The MSC was a tiny bit corroded, but once scrubbed a few times it’s just put the biggest grin back on my face.

It has a couple of broken components - a drop link and the classic bodged repaired front bumper part (see pics) - which generally brings me to my question/advice on recommissioning. 

I built this when I was 9 or so - and the paint is a bit scruffy.... And the stickers are a bit tatty now too.... but what are people’s thoughts on the best way to get this up and running properly again? Not sure how sympathetic to be - or to buy new bits and stickers? All the wheels spin freely - in fact amazingly well - so the bearings seem pretty sweet I think - and it’s quite incredible for the age and lack of use over 30-odd years.

I’ll fully disassemble, clean and rebuild I think...

List of known faults:
 

1) Snapped drop link

2) bodged front end repair

3) suspension is very saggy - buggy doesn’t return to full ride height

4) MSC needs a good clean. 
 

Pics below - but I’d welcome suggestions/thoughts on what to do with it.... (take apart, clean and reassemble???). I’ve got some 3300ma batteries and also a sport tuned motor which was going into the Monster Beetle...
 

Many thanks!

[mud4fun]

I would strip it, clean and re-grease it all (old grease can go hard), check the shocks, fit new O rings (as they go brittle with age and leak) and fill with new oil.

I would also fit a new electronic speed controller (eg. £20 Hobbywing 1060), a LiPo pack and a new torque tuned motor to bring it up to modern day standards.

Then go enjoy it. 

 

EDIT. I'm a recent convert to LiPo myself, was running NiCd's (not even NiMhs) for last 40 years. They transform the buggies, much lighter and a little bit more poke. I would avoid sport tuned motors though, these buggies prefer torquey motors as their 4WD drivetrain has more friction and transmission losses in it than touring cars or modern buggies. If you do fit the sport tuned then you'll need to drop a pinion size, probably even two. My daughter ran a Tamiya Super Stock RR (a sport tuned motor) in her Terra Scorcher for a week or so and didn't get on with it, we swapped it for a torquey motor.

[Golden]

Many thanks for this - very helpful. Would you recommend Tamiya ceramic greases for the gear box and drive shafts, and maybe a dab of 3in1 oil for the wheel bearings?
 

I still don’t fully understand the difference between the torque tuned and sport tuned motors though. I fitted a sport tuned 370 motor to the lunch box mini I have - and it absolutely flew in a straight line, but was completely unusable and would fall over and crash repeatedly. I went against every life-long instinct to go fast..(!) and refitted the original standard motor back in, and can enjoy the thing again...

So the torque tuned motor rather than sport tuned here? How do the two compare?

I’m also not sure on how to match pinion size to different motors - and what the effects are...? Is it relatively simple to get ones head around - or do I need to look it up on  table or something for best combinations? Less teeth equal less gearing.... but then if the motor spins up more quickly...?(!)  

I’m still not convinced by Lipos - seems far too scary re the whole burning-your-house-down-spontaneous-combustion-thing!

Thanks for your input. Much appreciated. 

[mud4fun]

I just use whatever grease I have to hand to be honest as long as it is plastic safe. I just get tubs of it from places like modelsport. I do use the specialist greases on some items such as ball diffs etc but generally just use a cheaper grease.

Yes, sorry, ignore me on the motor. I was talking more in generic terms rather than specific motors, I wasn't talking about the specific Tamiya motors. The tamiya sport tuned actually is quite torquey bizarrely. They really do need to work on their motor names 

Generally speaking smaller pinion = faster acceleration, bigger pinion = higher top speed. However, it is more complex than that. Some modern motors that can spin up to 30K+ rpm will often require a smaller pinion to avoid straining the motor, ESC and battery but the car will still have a higher top speed simply because the motor will spin much higher anyway. 

Also I change the pinion based on the surface, I find I can run bigger pinions on flat tarmac whereas on rough ground or grass the bigger pinion would cause overheating issues with motor/ESC so I fit a smaller pinion. Also if we are racing on a tight twisty track (such as our garden track) high top speeds are irrelevant so we use smaller pinions for quicker acceleration instead. Fast long tracks we may go bigger pinion.

Smaller pinions will generally give longer run times of your battery when used for bashing.

Yeah, I had same fears with LiPo but I just replaced the 8.4NiCd's I use in my thundershot with a 2S (7.4v) 4000mah LiPo, it gives roughly the same speeds but gives 4-5 times as much runtime in race conditions and the car is 200g lighter!

 

[Golden]

Thanks for the above - really helpful. I’m going to get cracking on the refurbishment and repairs  Over the weekend I think - and can’t wait to use it properly again!

[Grumpy pants]

9 hours ago, mud4fun said:

I would strip it, clean and re-grease it all (old grease can go hard), check the shocks, fit new O rings (as they go brittle with age and leak) and fill with new oil.

I would also fit a new electronic speed controller (eg. £20 Hobbywing 1060), a LiPo pack and a new torque tuned motor to bring it up to modern day standards.

Then go enjoy it. 

 

Great advice, simple, cost effective and succinct 💥

[davidwj95]

It looks like the A5 part (bumper mount) has had a few repairs.  This is a weak spot on these.  It would be worth getting an aluminium A5 part from RCmart.

[Golden]

Yep. Definitely need a new front piece (A5....) and will get a metal reinforcement bracket too. Just stripped it all down and it’s got wd40 or similar on pretty much every metal joint and bearing (which I really don’t remember doing.....) hence all the metal and original bearings are in great shape. 
 

Sadly the chassis has a snapped screw hole (where the front suspension and diff bolt into the chassis). Could bodge repair it - but there are still chassis available on Ebay for this generation (not sure if the new one is different as the old one needs the screw holes for the resistor....). Shame, as the cost of the few parts I need (as they’re part of larger sprues) is starting to mount up and I wanted to keep it as original as possible (I’ve had this broom for 35 years...).

The rear shocks have original oil in but the fronts are empty. Will post some pics over the next day or so as I clean it up and rebuild. 

Thanks for all the help. 

[mud4fun]

7 hours ago, Golden said:

Yep. Definitely need a new front piece (A5....) and will get a metal reinforcement bracket too. Just stripped it all down and it’s got wd40 or similar on pretty much every metal joint and bearing (which I really don’t remember doing.....) hence all the metal and original bearings are in great shape. 
 

Sadly the chassis has a snapped screw hole (where the front suspension and diff bolt into the chassis). Could bodge repair it - but there are still chassis available on Ebay for this generation (not sure if the new one is different as the old one needs the screw holes for the resistor....). Shame, as the cost of the few parts I need (as they’re part of larger sprues) is starting to mount up and I wanted to keep it as original as possible (I’ve had this broom for 35 years...).

The rear shocks have original oil in but the fronts are empty. Will post some pics over the next day or so as I clean it up and rebuild. 

Thanks for all the help. 

All chassis tubs are the same across all four derivatives including the re-re's

You don't need to buy an alloy A5, if you can get hold of the another rear mount B8 you can then fit that to the front, slice the old broken A5 in half and bolt that to the bumper. The lower part of the old A5 then clips into the square recess in the lower gearbox over the long screw and holds itself in place (you can slacken or tighten the screw ever so slightly to get a snug fit). By splitting the part you will find alot less stress passed through into the suspension mount.

All our thundershots and terra scorchers have this mod and all have done hundreds or even thousands of hours use with no further issues. In the event of a heavy front end impact the bumper can pop loose but is easily clipped back in place. We even did the same mod as part of the new build of my daughters brand new 2020 terra scorcher before it had even been used. We just kept the original intact A5 to refit if the buggy is ever sold.

Fitting alloy parts just transfers the impact forces into other places so it has to be carefully balanced between risk and cost of the areas likely to be damaged, typically the gearbox and tub mounts so you end up with even more expensive and time consuming damage and repairs.

This is a cheap and effective repair for a runner, the B Parts trees often sell for half or even a third of the cost of the A parts tree.

[Golden]

Thanks for this - very interesting - and I can see how B8 is identical in shape to the top part of A5...

There’s not much price difference in the A tree from the B sprues, but I can see the advantage in a two piece clip (using the bottom part of my A5 which is actually ok....) - and how it will splay upon impact rather than more likely cracking if it was a solid piece. 

Have fully stripped the car now and will start to clean all parts properly (am amazed at the condition - and I seem to have sprayed wd40 everywhere as mentioned above, which has preserved it quite nicely I think). 
 

Pics of the damaged parts below. It’s a shame as I’d really like to keep the original chassis for posterity (although it says “Thunder Shot” inside!) - but I don’t think gluing this part will even remotely work... they seem to be about £15 on eBay - but really wanted to keep the original... welcome folks’ thoughts on this - but I think it’s had it?

Cost wise it’s not massively off the re-re... (chassis, oil for dampers, various greases, drop link, A or B sprue, maybe some reproduction stickers ....) - but I kind of like the fact that it’s my original one.... apart from all the new bits on it!

 

[Grumpy pants]

Definitely replace, don’t repair, it will break again in a jiffy which would be disappointing and tedious.

The plastics are old and less robust now and they will be more likely to split, break etc.

As a runner that could well be used enthusiastically again you will end up replacing a fair bit of it anyway- triggers broom springs to mind 😂

[mud4fun]

If it is to be used as a runner/basher then I would just repair it, seriously I have run thundershots for decades that are full of cracks. My fastest thundershot which has just done over 1000 laps of the round 3 postal racing challenge has major cracks in its upper suspension arm/gearbox mounts AND it has a cracked tub with broken front mounting AND one of the gearbox mounting screw holes has worn away so the screw dropped out. It has managed to continue running perfectly well with just 2 screws holding the entire front end on.

So if it was me, why bother spending money until you need to, use epoxy and a thin metal washer to bodge a repair and just go enjoy the buggy. No need to spend a fortune to get it looking pretty if you are using it and potentially going to break it again anyway. Wait until it finally falls apart until replacing the broken parts 

[Golden]

I’ll have a go at a bodge repair and see how it is. It's been broken for a while I think, and only fell apart when I unscrewed it.... just wanted to guage views as to whether it would likely hold up - but will soon see I guess.

While I’ve (sort of!) got your attention - what damper oil should I use for the shocks - can’t seem to find anything with the Tamiya part numbers which are listed in either the old kit instructions or the new ones.... it’ll be bashed around the back garden and driveway. Looks like it’s yellow #400 damper oil -  top end of the soft range as standard. 
 

[mud4fun]

6 hours ago, Golden said:

I’ll have a go at a bodge repair and see how it is. It's been broken for a while I think, and only fell apart when I unscrewed it.... just wanted to guage views as to whether it would likely hold up - but will soon see I guess.

While I’ve (sort of!) got your attention - what damper oil should I use for the shocks - can’t seem to find anything with the Tamiya part numbers which are listed in either the old kit instructions or the new ones.... it’ll be bashed around the back garden and driveway. Looks like it’s yellow #400 damper oil -  top end of the soft range as standard. 
 

yeah, I use core-rc 350 cst oil for off road and 500 for on in all the CVA;s on all our buggies, seems to work for us. I'm not a pro racer so to be honest I doubt I could tell any difference in minor variations between grades LOL

I had same broken part on the tub I just swapped out of my thundershot. I only swapped it because I had a spare one that I had squared off the battery tunnel to allow a square section LiPo to fit in, the broken tub may well have been like that for 20 years and I had never noticed, it was the first time I'd taken the front gearbox off in decades. I will also epoxy a repair so we can re-use that tub for a basher buggy.

Yeah, try the bodge repair, at the end of the day if it gets the buggy running for minimum cost then it has to be worth a shot. Better for a buggy to be used if possible than sat on a shelf waiting until you can afford new parts. 

[Golden]

Thanks for this. Was umming and arring about how far to go with repairing it and think I’ll see how my bodge goes. And even make a little aluminium plate out of some sheet I have and epoxy that on if it doesn’t last. I like the idea of keeping my original buggy as much as possible!

Thanks for the guidance on the damper oil too.  

[Golden]

Back together after being thoroughly cleaned. Quite a few parts split actually - so lucky I’d bought some A, B and C sprues. One of the gear box casings had lost a screw fixing, and a wheel retaining triangle/hub had split too. 

I ended up taking EVERYONE’S advice - and repaired the chassis AND bought a new one in case it destroyed itself - so I have parts to hand!

I recycled the bottom part of my original A5 on the bumper and used the B8 part as recommended on the front bumper - so thanks to mud4fun for that. I also saw a really interesting fix on you tube using hop up shafts and a couple of spacers to change the way in which the front end wishbones are held to the front of the car, which I think makes sense, so might give that a go if it breaks again (as I have a new A sprue with a new part A5 to use).
 

 

I’d also mashed/kerbed each of the wheels, but think I’ve saved them with a little trimming of the lip with a Stanley knife - so overall, hoping it’ll run really well.

The gearboxes are a bit notchy and I was surprised to see the nylon gears catching on the inside of the casing, so shaved them with a dremmel but I don't think they mesh very well (there’s no apparent wear to the parts though....), and I cleaned the bearings in brake cleaner - whereupon they span up really nicely, but I then sprayed them with GT85 and now they don’t spin that freely - so may either replace or try a bearing oil..... or just leave it alone and get on with it already!

Looking forward to testing it out tomorrow in the daylight - and will then decide whether to repaint the shell - which wasn’t my finest work aged 9 or so (daubed I’m heavily with a brush) - or whether it might just need to be backed in silver and polish the outer surface and replace the decals.

The driver definitely needs some work though!

Thanks for everyone’s help on this. 
 

[mud4fun]

Good work! Think you may need new tyres if you decide to keep running it but go enjoy it for now 

[Golden]

My main hobby is actually working on old (full size...) BMWs, Peugeot’s and Imprezas - and I can’t help but restore rather than just get on with it or buy a completely new one.... (I think references to “Trigger’s Broom” have been made already!).

So... I started to try to clean the shell up a bit, as my 9 year old self hadn’t quite made it to the same levels of OCD as the 42 year old version, and the driver’s window had a bit of paint on it.... and I ended up stripping the shell about half way - using mentholated spirit and a cloth. I’ve read a few threads about melting shells and cloudiness, so took care to wash it in a bowl of soapy water every 20 minutes or so - and I’m going to leave it a day or so to see if it’s dried the plastic out/cracking or cloudiness comes through.I’ve ordered some repro decals from MCI Racing - so fingers crossed the shell doesn't suffer too much. 
 

[Golden]

Shell’s completely stripped (took around 5 hours in total - so two evenings in front of the tv... and used about a quarter of a standard UK sized bottle of methylated spirit). I’ve bravely decided to use the correct colour to repaint with (ps-4)(Although it’s been painted in ps16 I think for 32 years or so - and I don’t like change....). 
 

I did try the car out yesterday and it’s bl**dy brilliant! Stupidly forgot to reinstall the driver which covers all the electrics, so had to do another (far quicker this time....) mini strip and clean - and used compressed air/air dusters which worked really well.

 

You can of course buy an RC car which is far more capable and modern for not much more than the cost of the rebuild parts I’ve bought - but where’s the fun in that? Nostalgia and 80s retro cool every time. Really pleased it all works well - and thanks again for the advice above re the front end. Will post some pics when it’s repainted.