T2 Judgement day: my take on building a Terminator-chassis Clodbuster

[andymac0035]

This is another "looking back" thread. This would be the 2nd Terminator chassis clod I built, hence the name T2.

This is my take on how to build a CPE Terminator race-clod into a bash-worthy all-around-use fun monster truck.

I started building this truck in the summer of 2013. I built (and re-built) it several times over the next 4 years. I'd had a Terminator race-clod before, and it was not all I had hoped it would be. It was a bit on the fragile side and I really don't like link-mounted shocks. I had an idea of what I wanted to do, which was build one that mounted the shocks from the axle, to the chassis. Another thing was that while I prefer the stock chassis, I came to realize that old-school 4-link design on my 1st clod was putting too much stress on the C-hubs, where as the race-style 4-link would not.

I did many re-builds on this, so I want to concentrate on the final draft, but here's a few pics from the 1st draft. Notice the weird long ends on the shocks. Those were the only way to make things reach, and clear the tires. They are attached at the axle using mounting plates usually meant to extend the wheelbase, but instead the mount holes are used to mount the shocks to the axle.

The truck proved to be quite the hi-flyer once the right powertrain was added.

[andymac0035]

Okay, on with how it was built:

I built this around the idea to use traxxas titan "monster" 550's which are brushed 21-turn 550 motors, and an EVX-2 esc. The problems were clearing everything suspension-wise (more on that later), and gearing the truck up because the 21-turn motors were not fast enough for me on stock (13t pinion) gearing and I didn't want to deal with dual brushless at the time. Buying a set of adjustable motor mounts was easy enough, but fitting 19t pinions was not as easy. This required getting out the dremel.

How much bigger the hole needed to be:
(remove material ONLY from the side you want the motor to travel to)

Where that little retaining nut (for the anti-rotational bracket) is held, has to be ground off:

I retained the screw tubes, and drilled the clear cover to allow them to pass though, just like with the stock cover. Also had to add a washer to make it all flush.
Gear mesh is tricky, and best done with the axle off the truck...and keep a D-battery handy...you don't want the gears binding from being too tight. Also notice the cover is on backwards and I later had to take it apart and flip it around....

Side note, I also tried both gearing up stock 27t silver cans on 3S, and hotter motors on 2S, as well as stock gearing and hotter motors on 3S and stock motors on 4S. They all either ran too hot and burned out too fast, or had no low-end torque. It would have been a LOT easier to make things fit and work suspension-wise with 540's, but the 21-turn 550's geared up where the only ones to offer the best of both worlds.

[andymac0035]

I picked this servo mount up in a trade, dunno' if it's home-made or what, but it's a real sturdy one. Feels like it's made of steel.

This steering linkage would change a little, but this was the basically what I stuck with. I really liked how it it was tucked in verses sticking far out like so many axle-mounts do.

This linkage proved to be pretty strong and the mount would work itself loose. I figured it needed a 3rd point of attachment, and came up with this. This a a stock clodbuster short link bent a little and using stock ends and ballstuds. After that, it never came loose again.

You will see various links in some of these pics, but in the end I went with steels tow-links from the traxxas e-maxx. These were much stronger and had much better rod ends than any of the aftermarket clod stuff out at the time. Plus with them being tow links it was really easy to make alignment adjustments.

[andymac0035]

I suppose I should have said at the beginning, I only used a CPE Terminator center section. Normally you would buy the whole kit, but I didn't want any of the suspension bits as I was building my own. This meant that the anti-sway bars needed to be figured out. Normally you bolt a rod end to a machined link and it works like a slider on the end of the bar. I ended up threading the end of the bar and using these small P-clips to attach it.

Upgrading the stock bushings to 12x6 bearings is a must, but this is why I do not recommend the use of 5x8 bearings in a clodbuster. Use the stock bronze bushings if you are going to give it any kind of serous power upgrade. These bearings are just too small.

This is what happens, and sad to say I lost a few sets of gears because of this. Side note, at one time I turned this truck into a crawler, hence the locker seen in this pic.

Pick of it as a crawler:

[andymac0035]

I've stripped out a LOT of wheel-pegs over the years, to the point where anytime I buy a new set of wheels I do this, and bolt them directly to the stock drive hubs. The screws are 2mm (as opposed to 3mm). This truck does use wheels extensions. I used many different ones, but in the end settled on 1/2" mini-wideners from RC4WD.

I typically don't like gluing tires to the wheels. I would later go on to using shoe-goo on just one bead, but back then I used to glue rubber bands into the bead. This would give the friction needed to hold the tire from spinning inside the wheel, yet still let me take it off to get dirt and water out. I also would add 3 more breather holes to the wheels to get better tire flex.
(you can see the RC4WD mini wideners and barrel nuts in the background)

More to come.... but here it is right before I re-built it into it's final design, you may notice some suspension changes.

The terminator chassis is not very robust, it needs a lot of reinforcement..... as I found out.....

[andymac0035]

So now I'm getting to the nuts+bolts of this, here's the truck/chassis all torn down. Those plates are not supposed to be all wavey......

Shown here is a battery tray I made. It's intended to hold a pair of 2S hardcase lipos (wired in series =4S) to power the EVX-2 ESC. It sits on the terminator electronics tray, which has been flipped upside down with some added pieces that let me get it as low as possible. This was done, as the ESC and RX box are mounted on the side plates above it.

Clodbuster axles use braces, (long and short), these are 4 of the long ones, with the bent parts pounded flat and used as braces for the chassis. I had bent and straitened this chassis many times..... it never bent again after this.

[andymac0035]

So....
The key to making those long 550 motors work with the adjustable motor mounts that made them even longer, was going to a cantilever suspension. This had some drawbacks, as I had to mount the shocks upside down, which meant I had to be really picky filling the shocks with oil and getting all the air out of them. I used the cantilevers off of the traxxas summit. The mounting bolts were huge though, and I tried to get around this using smaller bolts and spacers but it didn't hold up. I had a 2nd set of suspension pieces like what I used for mounting the suspension and shocks to the axle at the start of the build, these were a little different and the holes all lined up with the holes in the chassis (the other CPE ones didn't line up). Unknown brand (got them in a trade). I drilled the hole out large enough to use the summit mounting hardware and that made it all work out. They also made great braces for that part of the chassis.

I needed some 6mm nuts, and used some for spacers up front, since they are not offset like the one's on the back are.

Here it is getting ready for the axles. If you look closely, you can see the differences in the front and rear cantilevers.

And here it is with the axles in place:

[andymac0035]

Onto steering:

When I originally built this it had a a vertical servo mount up front and no rear-steer. When I added the new steering mount (seen a few posts up) I had to reverse the steering on my radio. I only had a 2-channel radio at the time and never thought about dual axle-mounted servo's. Needless to say, that changed as now with a vertical servo mount put to the rear axle that had steering opposite of the front.... add to that the traxxas RX had 2 plug-ins for steering, and it was time to make the terminator 4-wheel-steer.


On the front steer I made up a new short link. This is nice because I was able to use a camber link in the middle of it. No more taking the links off for adjustments.

Here's the rear linkage. Both this and the one above were made using bits cut off of and axial wraith tie bar. Notice also that it's attached as close to the center of the servo saver as possible, as I didn't want excessive steer in the rear.
Yes, I know, it's rusty, I play in the snow a lot.

This video was taken shortly before this re-build, so a few things are different.
It was my 1st draft of the cantilevers using the smaller bolts and spacers and before I switched to hardcase batteries.
https://www.youtube.com/watch?v=PPYzQFzu3pk

[andymac0035]

And here it is all back together. Articulation was quite good.

I later got into the crawling scene with it. I didn't like it with 2.2's on it, but with giant tracs, or stock tires put on backwards it was pretty fun.

[andymac0035]

I ran the truck for a while like this on 4S (2Sx2) but eventually tried to do some weight savings as it was a pound heavier than my stock-ish clod that I had at that time (and that matters in deep snow). On 4S the truck topped out at 27mph with the 19t pinions, which made me pretty darn happy when I wasn't breaking something. The EVX2 esc ended up on the other clod and a sidewinder3 in brushed mode went into this truck. That lead to me using a single 3S hardcase and experimenting with removing the flux rings from the titan motors. I really wish I had thought of that sooner, because I discovered something.

a little copy+paste from my original thread on clodtalk:

With stock gearing (13t pinions)
On 4-cell lipo my terminator with flux rings maxed out @ 17mph.
On 3-cell lipo without flux rings top speed was.... 17 mph!
So it makes a difference. Makes me wished I had an esc that could handle 4S, I'd like to know how fast that would be (with 19t pinions).
But I went to 3S to save weight for handling, and snow-running.

Anyways, here's a video of it running when I 1st geared it up (but before the cantilevers)
https://www.youtube.com/watch?v=Ef6B29xMDBo





Some more zooming around and also my 1st feeble attempts at crawling with it:
https://www.youtube.com/watch?v=I4q1AQpMF4w

[andymac0035]

Here it is with a different body and the 4WS in place.
https://www.youtube.com/watch?v=wswOH5n3uLg



I ran it with this body for a while, but eventually went back to the jeep body.
....and as you can see..... I like running these in the snow.

[andymac0035]

Here's a few more snow pics with the jeep body back on it:

[andymac0035]

Here it is at the local R/C track during practice time. I was actually able to keep pace with traffic.

https://www.youtube.com/watch?v=3YBILoMs8_8





and here it is with the cantilever suspension in place.
One of the things I liked about the cantilevers is that they cut down on how much the chassis "rolled" back (under acceleration) making the front of the body lurch up ridiculously.
https://www.youtube.com/watch?v=NH-oRmxayH0



and in the snow:
https://www.youtube.com/watch?v=_zgftuIe8RQ

[andymac0035]

I tried lockers and crawling with it for a while, but it kept stripping out lockers and the rocks had worn the gearcases thin. The steering just wasn't good enough either. I figured 4WS would make up for lack of steering angle, but no such luck. Too many compromises that I didn't want to make at the time. I replaced both gearcases, but didn't mod them for bigger pinion gears (that's a mistake, I should have done that) and put stock gearing in it. I flipped the electronics tray right-side-up, which raised it up and I actually used it for mounting electronics. The rectangular holes in the lower part of the chassis are meant to be for the stock battery slot, which was now filled with a 3S hardcase, and that's the way it would stay. This "I-rock" body looked pretty cool on there. This is from the summer of 2016.

https://www.youtube.com/watch?v=Yw2Ar1icd1s

[andymac0035]

Crawling comp in 2016:

I had some axial crawlers by this time but could not resist bringing along the monster truck.

They had a pull sled competition. I did this pull after some 2.2 rigs set the weight (there's lead in that there sled). It pulled it out the gate easily. Needless to say.... I was asked to come back after the crawlers finished their pull-off. Then they tossed a bunch more weight in there..... and it still pulled it out the gate no problem. It took all the weight they had (lead heaped about as full as you could fill it) to stop me, and even then it went better than half-track. Pretty good considering how I'd lightened the truck and gone down to a 3 cell lipo.

It owned the articulation ramp.

Size comparison next to an axial SMT10

They had a hillclimb too.