Archive for February, 2018


Operation RESOLUTE BROWN: Vantruck Justice and Motorama 2018; Installing a Gear Vendors Overdrive

Feb 28, 2018 in Events, vantruck

I know I said I’d make this a lessons learned at Motorama 2018 post, but let’s go back to vans for a minute. Motorama 2018 would mark one year since the ill-fated Motorama 2017 trip which left Vantruck in a state of “de-shittification” for months, resulting in the post series OPERATION ENDURING BROWN .  Fortunately, for the past few months, it’s reached a stable plateau, even managing to go to a car show and on several large-object getting trips to New York…


(yes, it IS in fact in the middle of Upper Manhattan… who thought that was a good idea???)

…New Jersey, New Hampshire, and whatever else around here starts with New, as well as being the resident Bruh Can I Borrow Your truck, which has resulted in another two or so trips to New York State and New Jersey. Basically what I’m saying is, it’s been solely responsible for at least 0.0001C of global warming.

So I had to make Motorama 2018′s trip count. Now a year in the making, it was time to close the chapter of making Vantruck less shitty to begin on the journey of making it more gooder. Thus, we begin OPERATION RESOLUTE BROWN.

I decided the first major salvo would be getting it a fourth gear prior to Motorama. With only 3 speeds in the Ford C6 transmission and the top gear being 1:1 into a 4.10 ratio rear axle, getting the thing to go faster than 55mph was strenuous… not for lack of power, but just for sheer engine speed on the highway. Vantruck’s known repeatable gas mileage was a linear function of speed, more or less: 9 mpg at 55, decreasing to 8 mpg at 65mph and may Al Gore personally lobotomize you for trying to go 70mph consistently – the 7.5 liter V8 spun at 3,200 RPM or basically 80% of its redline just to keep up with the nearest Pumpkin Spice Lattemobile.

There were two major paths I worked with which people seemed to have done. One was swapping the transmission for a type E4OD 4-speed, which was used in Ford trucks in the later 80s and through the 1990s. That would have involved sourcing a functioning (or rebuilt) E4OD and also transplanting over the transmission controller or buying an aftermarket standalone controller. Beyond that, fitting the larger-cased E4OD would have involved moving and making new transmission mounting crossmembers. It seemed overall like the more correct but more involved route – it was not much of a stretch at that point to simply change engines with it by purchasing the entire running gear of a different truck. powerstroke swap

The other option was adding a discrete overdrive unit. Up until I started doing this research, I’ve never even heard of aftermarket bolt-on overdrive gears, but hey! They seemed much more common “back in the day” when less transmissions came with anything but 1:1 for the highest gear. They seem to generally work like large drill gearboxes driven in reverse, and are mostly of the deNormanville design, also called the Laycock (huehuehue) design:

Pretty nifty. It’s like an inside-out Roll Cake, for your transmission! The downside was that these things were quite pricy new – a full kit from Gear Vendors, the current manufacturer of these units, was going to run $3,000. My van salon estimated around $900 for installation including modification (cutting and rebalancing) the drive shaft. So in other words, both my options were going to be almost equally expensive with time economy, make-it or buy-it, and convenience tradeoffs.

We all know the real answer is “Tesla swap it” of course – if I had my own lift and garage, I’d probably have just machined my own overdrive box by running a PTO gearbox or some other kind of industrial dongle backwards with giant dog clutch and Overhaul’s old clamp actuator as a shifter. But I don’t – I have what I can do on the ground without a lift, often with snow cover.

After consulting with my vanstylists, I decided to pursue the external overdrive route. Convenience won out in the end, as the installation would be largely bolt-on with only modification of the driveshaft and moving one frame crossmember. I wouldn’t get the benefit of the locking torque converter of the E4OD, but would still see highway RPMs fall by 25% at least. It was going to be 80% of the results for a small fraction of the work of a whole transmission or powertrain swap. The only trick to making it really Econolinical was trying to find a used unit.

I set up traps on eBay and Craigslist and waited a few weeks, but it paid off in getting me a $1,200 unit removed from a truck the owner was parting out after a crash. This meant it must have been moving before the crash, which means it most likely works!

It was just very…. gooey. Obviously something was leaking, either it, or something onto it. Nothing I’m not familiar with! A few passes in the sink with degreaser and a small wire brush and it was as clean as I’d care to get it.

The unit came with the adapter spline, replacement tail housing for the transmission, and a whole bag of spaghetti that was the Gear Vendors auto-drive control system. I’m not going to use it. There’s all manners of lockouts and disables – primarily to keep the unit from activating in reverse gear or under 25-30mph when its internal oil pump would have a hard time keeping the clutches engaged. These sensor wires all end up in phone jacks in the control unit housing. Who picked that connector!?

Anyways, how about a switch and “don’t be a dumbass” for the time being?


For the first time, I’ve succumbed to the forces of practicality and paid someone for the installation of a major vehicle system. This is the beginning of the end :(

Well, as I said – the previous issues of having to work outside on the ground, in a below-freezing mostly snow-covered parking lot made installing this myself a serious impracticality, coupled with my much decreased time recently from tending to my secret whispers startup. I definitely contemplated trying to get everything except the driveshaft done, then only having my van salon do those modifications.

But for just under $1K, they put everything together (minus the control system installation, by my request) and in fact actually had an entirely new 2-piece driveshaft made, instead of cutting the old one. Okay, pay for nice things, get nice things… sigh.

Here’s a photo of that setup, including a new crossmember since the center hanger bearing had to be relocated. On the left: My own shoddy dirt floor chop job exhaust repair. <:(


I proceeded to wire the control solenoid up. All it needs is 12 volts to activate the shift valve!

The van salon did discover what had caused the unit to get so greasy: The sump gasket was loose and damaged. I ordered a new one right after the fact, but I haven’t been able to get under there to install it just yet. So for now, it dribbles small amounts of gear oil if I actually try to fill it up all the way. In the above photo, you can in fact see a drop forming.

What, one of my vans dribbling small amounts of oil constantly? Never!

One conundrum was swapping over the Ford speedometer cable drive end to the GM style threaded fitting that Gear Vendors uses. This was a problem to solve later! Road test NOW!

I grounded the solenoid nearby on the frame and ran a Little Red Wire all the way up the chassis wiring bundle which slinks between the frame and body, proceeding to wrap it the wrong way around the cruise control actuator in the process. It enters the cabin with the other aftermarket wiring.

I committed abject electrical terrorism and jumpered it to the fuel pump circuit, which has already been jumpered to… something I can’t remember. Oh boy, this will get interesting when fuse blows.

The final connections were made using a spare random switch I had, reinstalled into the famous “What the hell did this switch go to?” hole!

Some people buy or make an elegant on-the-shifter button switch solution, but I found it just as easy to swipe at the dashboard. Did I mention ROAD TEST NOW?????

I used a phone GPS speedometer to get a direct speed reading in lieu of having the speedometer cable hooked up. Basically, get on the highway and flip the switch. The satisfying thunk indicates the unit has activated. At 55mph, the engine RPM fell to around 2,100. The absolutely fantastic thing is that 70mph engine speed is now the former 55mph speed, at around 2,650 RPM. It’s now disturbingly quiet, with only wind buffeting in the cabin. Far quieter than Mikuvan – with its higher wind noise and lesser sound insulation and my fake racevan muffler.

It was in fact now too easy with the torque overhead of the 460 to start going 75mph and up without noticing. This is also where I found out it has a resonant, likely tire-balance related, issue at between 71-75mph. Once you break through that, it’s like crossing the sound barrier. I ran out of testicular tenaciousness at around 82mph and decided to not explore further.

I only forgot to disable it after getting off the highway once – which caused it to fall out of overdrive mode. There’s a sprag clutch connecting the two shafts which forces 1:1 mode if it can’t shift for any reason, and it will pick up again as soon as the input shaft spins fast enough. From what I understand, this isn’t the end of the world, but also isn’t good for the cone clutch linings, so I’ll just have to Get Good at remembering to turn it off. (I didn’t mess up once during Motorama!)

A couple of days later, my speedometer parts came in the mail.

I bought a common 20″ GM style extension cable which has the 7/8″ threaded coupling on both sides. GV gives you a big bucket of hardware to adapt to like every possible speedometer situation, but the seller didn’t end up having to use the extension cable originally and so did not include it. I literally got a chunk of the speedometer cable of his truck, which, while well-meaning, was less than helpful.

The Ford speedometer gear comes off with a small clip and the fitting behind it gets shoved into the aluminum adapter provided by GV. There’s nothing holding these two together except the friction of two O-rings, which is fine I guess.

The GM male fitting tightens into the other side of the aluminum tube.

The female nut side of the GM cable then tightens onto the fitting on the GV unit. I just kept everything held up with a few cable ties after that, and we’re done here.

And to remind myself of my escapade…

Was it worth it? In terms of reducing the wear and stress on the engine just trying to puff along the highway, yes. Economically, with around $2,200 spent all up, it would at first glance take around 15-16,000 miles to pay off at around 2.69 a gallon average and around 9 MPG. But then I have to remember that 9 MPG is now at 70-75mph instead of 55… With more comprehensive testing, 60-65mph driving results in slightly over 10 MPG so I bet 55mph is going to see above 11.

However, I’m never going to bother going 55mph again. The gas mileage argument is really kind of moot to me also. It was just good to move at real-people speeds.

All of this happened in the 3 weeks before Motorama after I got back from CES and had a brief escapade to Atlanta. January was a crowded month. But I’m proud to say that Vantruck Justice was achieved!

huehue we touched butts

I met up with Alex Horne for DOUBLE VANTRUCK PARTY . Stay tuned for how Clocker did at the tournament, and how that affects my strategies and design paths for Overhaul!

My Life is Ruined Again: BattleBots Season 3 and the Triumphant Return (?) of Overhaul

Feb 21, 2018 in BattleBots 2018, Overhaul 2

> mfw season 3 announcement

The rumors began shortly after July, when Science Channel announced it was going to pick up BattleBots after ABC unceremoniously shat us out in favor of a …. boy band show? Well fuck me sideways with a fracking well, look at how that turned out for you guys! The rumors intensified in November as discussions and negotiations were clearly under way, and reached a crescendo in January, each week leaving us wondering if “next week” was going to be it.

Well, now they announced it. Crap. Now I actually have to finish something!

Overhaul’s upgrades have been in in the works – albeit slowly. After season 2, I had a whole list of changes I wanted to make and “design regrets” resulting from the extremely fast build season and required turnaround time I wanted to address. Really, I (and a lot of other builders) see #season3 as a chance to do Season 2 “correctly”, addressing things that didn’t go the way we want or designs that could have been done better. And frankly, anybody trying to build from scratch for the season now is either a dumbass or more of a man than I

that apparently ain’t hard

So that’s where we are now. The story of Overhaul upgrades actually goes back to right after Season 2 ended, and starts with what is basically the last large mechanical assembly that was designed, the clamp actuator…. meaning it was the most rushed and horrifying.

Ball screws were a bad idea. I was attracted too much to the promise of 90+ percent transmission efficiency, but they ended up being too fragile and also had the nasty habit of backdriving – made most obvious in my match against Beta. During the following 3-bot rumble with Sawblaze and Road Rash, the ball screw stripped out almost completely and began acting like an Acme leadscrew anyway.

Trust me, that hurts me viscerally to look at.

There was also a confounding problem with the actuator design and the clamp arm. In general, the actuator ended up too bulky to hide effectively without making the head ungainly. Because of the positioning of the motor and the bulkiness of the ball screw, I chose to simply add a little ‘horn’ to the clamp arm (the protrusion close to the pivot point) in order to protect the actuator motor from being landed on if Overhaul got flipped over.

In order to get the clamp running again quickly in case Season 3 happened relatively soon (*ahem*) and to explore the large Acme threaded rod market, I actually designed and machined up a retrofit using 7/8″ Acme screws and nuts – the odd size was for the easiest fitment to the existing actuator bearings, since the root of the 7/8″ Acme thread form required minimal machining to fit.

Also, I found the nuts on sale on eBay for like $20. There’s an engineering justification for every spur of the moment purchasing decision.

I wanted to redesign the whole upper half with a new acme screw based actuator to solve this. Furthermore, I wanted to move from a live-screw design to a dead screw one, where the actuator contains the mating nut within large carrier bearings and simply rides up and down a stationary screw, which is the design I’ve historically used for Überclocker.

The premise went from using the higher efficiency transmission option to the more durable and simple one and just overpowering the everloving fuck out of it to get my desired closing forces. As a large portion of combat robots revolves around the latter, it was clearly the way to go.

I cloned the Overhaul 2 CAD model into a new directory so I can start messing with everything. Here we go!

This is the actuator in its current position in the bot.

I wanted to try and see if I could move to a pull-stroke closing like Überclocker has been running. In general, the answer is “not really” due to how far the actuator will stick out into the ‘grabby zone’. In Überclocker, I sacrifice a whole lot of leverage to position the actuator almost vertically so it’s much more out of the way. I wanted to not make that sacrifice for Overhaul unless I had to, or if it were super convenient. functional requirement: be lazy

I also investigated the idea of flipping the thing upside down. In this configuration, if the trunnion tube is made non-offset (inline with the leadscrew) the motor will unfortunately hang down very low into the ‘grabby zone’ and be vulnerable.

All of this position testing though was enough knowledge for me to begin hashing out the next part of the design.

For now, I just imported the model of the P90X gearbox which was never quite implemented. Into the same model, I imported a bearing I bought on McMaster-Carr which I got curious about while specifying new thrust bearings for the this thing.

These are “one piece” ball and tapered-roller thrust bearings, so-called since McMaster usually sells thrust bearings in little kits of 2 washers and a basket of round things. Don’t be fooled, though… the “one piece” part is just a stamped sheet steel shell that holds the two bearing halves vaguely together.

The one on the right is a ball bearing based one, and the left one is a tapered roller bearing which is basically tapered the ‘wrong’ way compared to a normal one. This means it can support almost no radial load but a ton (or approximately 7 tons) of thrust load!

I found the tapered roller bearing one a little janky, though. The full roller complement meant it had quite a lot of drag when rotating, and the packaging was a good 3/4″ thick. There’s also no way I can reasonably use its 14,000 pound rating …. and that’s an industrial rating, mind you, meaning it will happily do that for thousands of hours and not just 3 minutes. So I chose to move along (for now) using the ball version, which only has a …. 7,000 pound dynamic load rating, but was thinner and lighter.


The brown object in the middle is a stock round Acme 1″-4 nut that will either be machined as a gear (quick modeled as teeth here) or have a machined ring gear shoved around it with a thermally-enhanced intereference fit (LN2 the nut, bake the gear, shove them together and run away fast)

You might be wondering what the plan for radial loads is, since ostensibly I have two thrust-only bearings designed into the thing so far. The fake answer is that the leadscrew nut, being bronze, will just ride in the stationary bore of the thrust bearings, since the magnitude of thrust loads will be much higher than potential radial loads on a stationary leadscrew.

The real answer is “yolo”.

Here I am playing with actuator positions again. The “pull-to-close” position in this photo mimics that of Überclocker.  I still felt that the important parts were too exposed here.

Another attempt just flips the actuator upside-down and exposes pretty much only the leadscrew. This was at least tolerable in conception – something being mashed into the leadscrew (which could also be shielded) might still leave me enough travel to get a good grab.

Okay, but what else did I learn from Season 2!? That if you leave something important exposed…. say, a master power switch or similar, and run on the assumption that the chances of something getting into there and causing damage are very low, then it will happen to you 100% of the time.

So I gave up the “pull to close” actuator position in favor of just trying to keep the leadscrew short and fat in order to maximize its column rigidity.  The bonus upside is it woud let me keep the existing center hub between the two arms if need be.

This positioning candidate was actually pretty favorable. I could see how the clamp arm geometry might be changed slightly to better accommodate it, and also permit it to use a relatively short leadscrew

Using the geometric constraints put forth by the toy component placement,  I basically wrapped an aluminum chunk around it. The cavities are for the gears and bearings.

I changed the design to an “embedded P80″ to save length. The clamp motor is being moved to brushless, meaning Overhaul will be completely powered by questionable Chinesium. This time, since the Acme screw will not backdrive, I don’t have to hold the stick to apply pressure to the clamp arm any more, making it more Clocker-like in driving. Furthermore, this also affords me the opportunity to overpower the actuator while keeping a high gear ratio for force application. Überclocker’s current actuator is a regular 36:1 geared 550-class drill motor run at over 2x nominal voltage for moar powar – the short duty cycle of a grab and lift haven’t caused motor burnout problems.

A couple of different brushless motors could fit on this gearbox – right now, the SK3-6374 motor is in for modeling purposes.

Adding more parts and thinking about how to interface to the rest of the bot. The large rod-end is a convenient way to join to the wrist pin in the lift hub.

The design is more or less finished here. Those 4 square holes in the side are actually on a 2.25″ bolt circle, so four 3/8″ screws on each side will fasten the actuator to machined trunnion plates. I may end up making 2 of them dowel pins for shear strength and leaving only 2 as threaded holes.

With the new much more compact design, I was able to get a happy result for placing the actuator within the head. This was a good state to reach – I now have a solution where the trunnion bolt holes line up with the circular arc containing the patterned circular cutouts which Overhaul is known for. As a result, I can just hijack one of those holes (appropriately repositioned) as a trunnion axis, much like it is now.

All of this work occurred in the late December to mid January timeframe. I receive the new actuator billets and custom leadscrew nut back from my Chinese contract manufacturer this week.

In the next episode of Overhaul’s Improbable Overhaul Makeover?, I travel to Motorama 2018 with Überclocker in order to practice driving and strategy – and learn some disturbing new information which might disrupt my #season3 ambitions…