Kronos XTR Horatio's XTR Build

[Horatio]

Hi guys. I detailed my build step by step in November 2021.

My review as I go along is frank. It has lots of photographs and really the only mistake I made was to post it onto a forum that is now barren and broken.

Please visit RC tech below, a forum that had so much to offer for so long. So much techy stuff.

Kronos XTR Build On RCtech

As always PJ is first on the scene. She couldn't wait to see what I was getting up to!

New car smell! Size-wise, the wheelbase is very similar to a race truggy.

This is quality stuff. Look at this and compare it to the typical basher stuff out there. This isn't cheap tat or crudely stamped out monkey metal. Very nice!!

Time to compare with an old skool monster....

Body has a crazy graffiti vibe going on, mixed with a retro 50's style dorsal. This body will divide the crowd. But no-one can claim that Arrma bodies are any better looking.

Magic combo of Torox 185 Kuron 825.
Why is it so quick? Are there any other stock combinations that come close?

Spare body painted.

Lights and grill under the body.

This is a nice safe place to keep your lipos.

Battery tray - this bolt goes into a regular nut. I decided to use a lock nut. No brainer.

Dual lock - velcro, reinvented. You need this, you just hadn't realised it. You're welcome!

Keeping everything as neat as possible.

 

[AngrySection8]

Gotta love the savage! Out of the 7 I've had I've still got 3, your tvps look a bit longer than standard length but not quite xl? Maybe it's the angle, nice xtr too!

 

[Horatio]

Servo installed. This combo is smooth, quiet and centres as well as my Protek 170 SBLs - but it's waterproof and a fraction of the cost.

3VCS is my Radio of choice. Yes, really! Sticks only for me. It was either that or....

...this!!

Gens 6S 4500 battery provides 'more than adequate' power. To put it another way - it's F#£@ing ridiculous!!!

This machine is just waay too much fun, but The Kuron 825 isn't supposed to get as hot as a nitro engine, apparently.

Time to stop the outside getting inside.

Keeping this machine running right requires combatting heat. Running in February showed me that the heat levels weren't going to work for me come the warmer weather.

So, geared up to find out what this machine can do!

No more chippings or grass

Free of dirt, dual fans keep air flowing through the finned heat sink. Heat battle won!

Time to fix the servo saver.....

Solution = Found!!!
Thanks to great minds like Dani C that worked through finding a company that could produce a music wire spring to the exact requirements.

Subtle fettling to improve clearances on tranny case improves steering throw.

Steering that works shouldn't be underestimated. Especially at high speed.

Gotta love the savage! Out of the 7 I've had I've still got 3, your tvps look a bit longer than standard length but not quite xl? Maybe it's the angle, nice xtr too!

Those are my lovingly machined FLM tvp's. They're worth a £1 million. (Ebay £35).

This rig on stock gearing and electronics flies past the camera at 62mph having achieved 0-60 in 4.28 secs.

 

[KnowAir]

Super clean build! I don't think I have a single rc as clean as even the Savage you pictured,LOL.
TBH, I couldn't be bothered to clean an rc to that level. Just not in me.

 

[Horatio]

Super clean build! I don't think I have a single rc as clean as even the Savage you pictured,LOL.
TBH, I couldn't be bothered to clean an rc to that level. Just not in me.

I rag them around in filthy, muddy, grassy conditions. But the Savage was lovingly restored in 2019. It's old!

It was literally a total rebuild, under the watchful eye of PJ of course.

Running the truck in wet grass etc does result in some major cleaning afterwards. The problem is, my rigs would never be allowed back in the house otherwise!

In it's day, this was how I raced it. 19 years ago....

They are supposed to get down and dirty though.

 

[Horatio]

For anyone that wants to see the detail of this rebuild, it's here.:

Savage Rebuild

 

[Horatio]

Super clean build! I don't think I have a single rc as clean as even the Savage you pictured,LOL.
TBH, I couldn't be bothered to clean an rc to that level. Just not in me.

I think right back to the 90's, it was instilled into me to always brush/blow cars down in between heats. Even when racing indoors.

So bearings, pivots, bushes and anything ferrous get serious attention following a run.

These days it can be weeks in-between runs, so cleaning isn't so bad.

Time to fit the HD hubs and Swiss Steel outdrives on the centre diff now.

 

[KnowAir]

I think right back to the 90's, it was instilled into me to always brush/blow cars down in between heats. Even when racing indoors.

So bearings, pivots, bushes and anything ferrous get serious attention following a run.

These days it can be weeks in-between runs, so cleaning isn't so bad.

Time to fit the HD hubs and Swiss Steel outdrives on the centre diff now.

Well, for racing and "inside house" storage, I'd likely do the same. For backyard shenanigans and "cold storage" in a detached garage, I don't have to bother.

 

[Horatio]

Well, for racing and "inside house" storage, I'd likely do the same. For backyard shenanigans and "cold storage" in a detached garage, I don't have to bother.

I've just pulled the trigger on this.

 

[KnowAir]

I've just pulled the trigger on this. View attachment 4393

Ooh niice! That's high end stuff!! Let us know how it performs. Great I'm sure. I can indeed appreciate the finer things even though I can't afford them. TBH, I doubt I'd notice much of a difference in my rigs being they all are pretty much rtr grade electronics equipped. Enjoy!!

 

[Horatio]

So looking over the Kronos today,

Ooh niice! That's high end stuff!! Let us know how it performs. Great I'm sure. I can indeed appreciate the finer things even though I can't afford them. TBH, I doubt I'd notice much of a difference in my rigs being they all are pretty much rtr grade electronics equipped. Enjoy!!

I want to give the XTR another speed run. This should help.

The centre diff has been blowing fluid.

So it was time for a rebuild of the diff. I needed to fit the new spring steel outputs anyway.

Turns out, the steel spur was getting loose. 2 of the screws were backing out and thus fluid was escaping.

Probably explains why the diff was getting warm - what little fluid was left was having to do all the work.

Fresh oil. I'm sticking with 100000 for now, but I might up this to 500000 if I keep ballooning my front tyres. Very unlikely with my Jetkos on speed runs, but an ever present risk with my stock tyres. I don't want to shred them though, they work well on grass ...... When they're on the ground!

Diff all shiny and new.

Now the pinion. It forever gets loose, the little f£#@er. It's thread locked etc but still it has a mind of it's own. I don't want it to part company or damage the spur.

I'm not all that keen on using thread lock on the motor shaft, otherwise I run the risk of having to blow torch it off!

My feeling is that for this scale, whilst mod 1 works fine, the pinion and grub screw are far too weedy for this kinda rig.

Please someone - design a beefier pinion! Turtle Racing - I wish they'd do 1/8th pinions.

 

[Horatio]

I just put some magnifiers over my eyes.

Just found out that thread lock on weedy grub screws accumulates at the top of the thread, like a flange!

The weird thing then, once it's fully hardened, is that when you attempt to tighten the grub screw, it doesn't clamp down onto the flat of the motor shaft.

I had to chisel the threads and clean it. Best course of action would be change the grub screw. But it's howling outside and I can't be bothered venturing into the shed.

This is where a good percentage of my diff fluid ended up.

Looking much better after a good clean.

 

[KnowAir]

I just put some magnifiers over my eyes.

Just found out that thread lock on weedy grub screws accumulates at the top of the thread, like a flange!

The weird thing then, once it's fully hardened, is that when you attempt to tighten the grub screw, it doesn't clamp down onto the flat of the motor shaft.

I had to chisel the threads and clean it. Best course of action would be change the grub screw. But it's howling outside and I can't be bothered venturing into the shed. View attachment 4407
This is where a good percentage of my diff fluid ended up.

Looking much better after a good clean.
View attachment 4409

I was gonna say the threadlocker builds up on the threads..preventing proper tightening, LOL.
Whenever I have a pinion come loose, new grub, use it to chase the threads in the pinion. Run it as far as possible into the pinion while the gear is off the motor. That should break up the old threadlocker. Then remove the grub and reinstall with fresh threadlocker. Works for me.
I have found the aluminum diff cups are more hassle than they're worth for my use.. meaning I have experienced the screws backing out several times from the spur..actually chewed up the center diff and motor mounts one time..
Problem I have is the aluminum cup needs to be completely oil free or the threadlocker doesn't work.. this is a non issue with plastic diff cups. The screws don't back out.
Aluminum cups shouldn't be necessary IMO. The only time the diff gets hot enough to melt plastic cups is when the fluid is too thin for the conditions, excessive "diffing out" from thin fluid creates excess heat. Use thicker fluid to prevent overheating the diff.
As to the pewny grub screws found on most M1 pinions, I buy Tekno M1, they use an oversized grub. I think it's like 5mm? They're the bee's knee's

 

[morrjr71]

As to the pewny grub screws found on most M1 pinions, I buy Tekno M1, they use an oversized grub. I think it's like 5mm? They're the bee's knee's

The Tekno pinions are the only ones I use now: you can get more torque on the larger grub screws. I've never had one come loose.

 

[Horatio]

I was gonna say the threadlocker builds up on the threads..preventing proper tightening, LOL.
Whenever I have a pinion come loose, new grub, use it to chase the threads in the pinion. Run it as far as possible into the pinion while the gear is off the motor. That should break up the old threadlocker. Then remove the grub and reinstall with fresh threadlocker. Works for me.
I have found the aluminum diff cups are more hassle than they're worth for my use.. meaning I have experienced the screws backing out several times from the spur..actually chewed up the center diff and motor mounts one time..
Problem I have is the aluminum cup needs to be completely oil free or the threadlocker doesn't work.. this is a non issue with plastic diff cups. The screws don't back out.
Aluminum cups shouldn't be necessary IMO. The only time the diff gets hot enough to melt plastic cups is when the fluid is too thin for the conditions, excessive "diffing out" from thin fluid creates excess heat. Use thicker fluid to prevent overheating the diff.
As to the pewny grub screws found on most M1 pinions, I buy Tekno M1, they use an oversized grub. I think it's like 5mm? They're the bee's knee's

Great tips, thank you. I'm going to order some Tekno M1's then. Makes sense to me.

I degrease my bolts and grub screws prior to applying blue loctite, but here the issue is just the way the thread lock has got it's panties into a wad.

I'll have a look for some fresh grub screws. I don't have a small enough tap, so nice clean grub screws should do the job. The thread in the pinion is ok. It's just weird how the the thread lock stayed on the upper portion of the threads and made a hat.

The grub screw on this pinion is about as big as it could be given the design of it - presumably the Tekno one have a little extra meat to work with? Either way, I'm sold on the larger grub screw. Cheers!

 

[KnowAir]

Just checked Tekno site, m5 grub screw.. they're my go to for sure. I use others, but only buy Tekno when replacing nowadays.
https://www.teknorc.com/?s=Mod1+pinion&post_type=product

As to the aluminum diff cups, my problem has been getting the threads in the cup clean..I have a tendency to make a mess of things and usually end up with slicone fluid in the threads.. no bueno with threadlocker.

 

[Horatio]

Problem now is finding Tekno 4173 13t Mod 1 M5 5mm grub screw in the UK.

In almost every instance, the pinions are coming from abroad. Unless I want to go from 13t to 17t.

£13 for pinion. £20 for postage. FFS.

 

[KnowAir]

Problem now is finding Tekno 4173 13t Mod 1 M5 5mm grub screw in the UK.

In almost every instance, the pinions are coming from abroad. Unless I want to go from 13t to 17t.

£13 for pinion. £20 for postage. FFS.

I was wondering about availability in your region.. they are pricey (Tekno) worth it for me, but not hard to get here in the states.

 

[Horatio]

I was wondering about availability in your region.. they are pricey (Tekno) worth it for me, but not hard to get here in the states.

I have no qualms paying £13 for a decent pinion - just not the £20 for the shipping. I'll find one. I'll have a chat with the UK Tekno importer, RPRC distribution. I need to have a little chat with them about an ET48 2.0 anyway

 

[Horatio]

Onyx 6S pack arrived today. It's really nice and everything, but it wasn't supplied with the XT90 that I selected.

I'm sure their fancy-ass plugs are awesome, but I'm not prepared to swap everything out.

So, female XT90's are with me tomorrow. Thursday the weather should be fine. Last chance, because Friday I'm off to the Edinburgh Fringe Festival.