Gristle McThornbody EB410 Build and Questions

[GMcThornbody]

Ordered my EB410. This is the thread I'll be asking setup questions and documenting my build progress.

The track I'm racing at is outdoor, primarily dirt. There may be some clay in there, but the material is sunbaked and pretty hard and dusty. Relatively smooth, though. They pretty much run open everything, so I haven't selected a motor just yet. I have an older setup with only a few runs on it, Tekin RS and an Orion brushless, but I don't recall the turns or kv of it. I'll have to get it out of the vehicle it's in to see, but I plan on using that for the time being just to save some of the up-front money. Same with the servo. I know it's a plenty capable servo, but I don't remember the specifics.

This is what I'm using as a baseline set up, but I'm open to any modifications people think I should make. http://site.petitrc.com/setup/tekno/setupeb410/EB410_BrianJames_Rome20180610/

First question I have is regarding recommended tires. From what I've read, it sounds like a good baseline is either Proline Holeshots (m3) or Jconcept Double Dees (blue), with one recommendation of AKA Impacts or Gridirons. Any other recommendations or suggestions. That information I found was a bit old, so something may have come out that's way better.

Other question, that I may just be overlooking while reading. What springs and sway bars come with the base kit? It's probably listed on the website, but my eyes are just flipping past.

 

[GMcThornbody]

Continuing to log my progress. Ordered my buggy. Upgrades ordered with:

Tekno Aluminum Servo Horn
Tekno Carbon Fiber Top Plate
Tekno Aluminum shock caps
Tekno Rear Sway Bar Set
Tekno Front Sway Bar kit (was honestly surprised that the kit doesn't include a front sway bar)
Tekno Orange Rear and Green Rear springs
Trinity Aluminum Steering rack and bell crank
Yeah Racing "Tornado Plus" cooling fan. I'm sure'll totally live up to Tornado and not burn right out.
ProTek chassis protector sheet.

Grabbed a few front end spare parts as well. I know Billl Delong gave me a good list, but it was a bit much all at once (however much appreciated information. Thanks, man!). I'll probably grab a few more things on the list on my next round of picking up stuff.

For wheels and tires, I picked up Pro-line Velocity rims, as generally any wheels seemed as good as the other as long as they fit right. For Tires, I got JConcept Double Dees in Green. Of the JConcept Double Dees, Proline Holeshots, AKA Impacts, or Gridirons, that's all that I could order a full set of front and rears that one or the other wasn't on backorder. Go figure.

 

[brianscotch]

Thanks for logging this. Just ordered an EB410 too, am going to run it a bit before I do many upgrades but this will give me a good starting point.

 

[GMcThornbody]

No problem. To be fair, some things I ordered were either because what's included isn't the baseline set up I'm following (springs, rear swaybar set) or things I'm surprised weren't included at all (front sway bar kit) The servo horn is just something I do to every vehicle that isn't a low speed fun time car. The top plate wasn't much more expensive than other motor fan mounting positions, and racing in the daytime in the southeast US with high powered stuff, I can't imagine the fan really being optional.

The aluminum bellcrank and chassis protector, well the bell cranks are easy to break anyways, so it was a choice between ordering a spare stock, or getting an upgrade I was going to get anyways and still having the spare stock. My experience, with the old monster truck class anyways, was that the front end parts are what takes all the beating. So beefing up and stocking spares for that end was generally a priority for me. Heck, my racing Revo had full RPM front end parts, and never broke anything on it again after that. Not exactly ideal racing set up, but sure was bullet proof. But then again, monster truck class was like racing high speed, well suspended shopping carts and I loved it.

The chassis protector was purely by choice. I just want to keep the bottom from getting too scratched up. I've never needed one, but it's nice to have clean screw heads if you ever have to tear down that far.

 

[GMcThornbody]

Stuff came in. Started my build. Built the diffs without oil for the moment, as the oil is coming in a separate shipment. I must say, to call the fitment between the diff gear case and the ring gear tight is an understatement. First I had to file just a touch of a chamfer (maybe 1/3 of a mm, if that) around the case edge to get it to fit inside the ring gear teeth. There was just so little tolerance, I couldn't get it lined up. I'm not entirely convinced that the plastic had a touch of flare making it wider than the inner diameter of the ring teeth. Then, the first one fit so tight that I almost couldn't separate it back out, much less spin it to line up the screw holes. After separating it, I left the front and rear diffs just loose. Put the screws in just enough that everything is secure and in one place until the oil gets in.

Also, regarding the 0.5 mm shims for tuning. Any recommendations on where to get more, or is there a bag in the box full of them somewhere? Not sure if I'd trust what comes out of Lowes or Home Depot. I figure I'll have to head to the hobby shop to get them but I'm open to suggestions that may be more convenient.

 

[devnull]

I'd like to know where to get a selection of shims too. I was poking around Amazon recently looking for some and didn't find much. Their search feature tends to try to show you everything under the sun except for what you are actually looking for at times. It's annoying, but that's just kinda how it goes when they're trying to sell.

 

[GMcThornbody]

Continuing this journal, for those who come after me. I hope it'll provide some insight and prevent some hiccups to folks like me who haven't built many race kits. I've built plenty of bashers, but those aren't nearly as tightly built so even I'm learning some new stuff.

Diff fluid came in last night, and I had a bit of minor disaster. As I said before, I partially assembled the diffs just to have all the parts in one place. For the front and rear diffs, I'd just threaded the screws in enough to keep anything from coming loose or falling out. However, for the center diff I had things a touch more snug. While not tightened, I basically stopped as soon as the screws were flush to the to the spur, but no tighter. Last night, one of the hexes stripped out when I went to loosen it. Then on another diff (the rear one, but front and rear are identical) one of the hexes started to strip out when the screw still had about 1mm to go. I went and knocked about 1.5 mm off the tip my hex driver with a dremel, but I'm not entirely sold that it was just the driver being worn out. I'm going to the shop tonight to get a new driver, hopefully they have some M2.5x10mm screws and if I'm lucky, they'll have some shims. You'd think they would, but unfortunately my LHS caters only to bashers with no immediately local race scene. So who knows what I'll find.

So lesson to new guys and a reminder to old. Check those drivers, especially that little 1.5 mm one. If it feels loose, just save yourself the trouble.

Additionally, if you're like me and have very few gear diff builds under your belt, the diagram for filling the diff fluid in the manual is... misleading. The picture shows fluid to just over the spider gears, but the text says (unless I was just having a moment and misreading) to 1 mm from the top. Well, it's closer to the picture than the text, as now my front diff will have amazing skin, thanks to the silicon bath it took.

For the most part, the rear end went together with no issue. I'd say be a little generous with lubing the threads on the turnbuckles. I went stingy and have rods popping off when I try to adjust them. I'm hoping it'll work in a little with time, but until then, well... my $15 digital harbor freight caliper will be a great investment, as one side currently it's just easier to pop the rod off and adjust it.

 

[TBuggy]

You should get some MIP hex drivers and you will soon realize it was the bits fault. I have stripped the same screw you mentioned once. When re-building the diffs (any part of the car really) if I have the slightest sign of a screw starting to strip I throw it out and replace it.

I have a very detailed build log for the ET410 and the build is identical with just a few differences in parts.
https://www.teknoforums.com/threads/tbuggys-et410.516/

 

[brianscotch]

Out of curiosity, did your kit not come with the oils, grease and thread lock? What oil are you using for your diffs?

 

[TBuggy]

yes the kit came with oils, grease and thread lock. The kit oils from what I have heard are very similar to PT oils so that is what I have stuck with when changing or needing different viscosities.

 

[GMcThornbody]

As mentioned above, it did but I'm running 15k/30k/7k in front/center/rear. Lots of setups for clay/indoor, but the one setup I found for outdoor has thicker center diff fluid. Not surprising, since it's going to dry, dusty and loose, want to lock up the center diff a bit more than stock.

So, continuing, I followed the above advice, picked up some MIP drivers. A WORLD of difference from my LowBucks Racing drivers, especially in the 1.5 mm. Also, holy crap, good luck finding M2.5x10mm flat head screws. LHS didn't have any in stock, and was even a little surprised I was looking for them. They ordered them just for the future, but with my LHS, that could be 2 weeks before they showed up. The guy suggested maybe trying Fastenal (basically a chain that deals primarily in screws, bolt, and fasteners of all kinds) but they don't stock smaller than M3 in the store. So, thank goodness for Amazon Prime, and I'll be set for life for M2.5x10mm screws.

Front end went together well. Learning from my mistakes and from TBuggy's build, I was much more generous with greasing my turnbuckles. I didn't follow his drill idea, but I do like it. I may have to reseat the ring gear on the diff a bit. I can't tell if I was imagining it, but after full assembly it felt like there was just the ever so slightest bit of occasional resistance when spinning the drive train. Wasn't there before everything was put together, but felt like the ring gear on the diff was just ever so slightly out of true.

 

[devnull]

It sucks waiting for something like screws that holds up your build/fix.

I bought a wide range of screw kits for flat head socket head, socket head cap and button head screws in ss and steel. There are a few gaps from 1mm up to 4mm, but not many (well, the really small ones, M1, M1.2 and M1.4 are phillips head). I have the M2.5 you mentioned in ss, but haven't found a kit for steel M2.5 at this point. Looked through eBay and Amazon, didn't find one. I suppose there just isn't much demand for it. Just bought some long M3 & M4 cap screw kits too. I definitely don't like waiting.

 

[GMcThornbody]

Had a productive weekend, with a few hiccups. Save for shocks and wheels (which I hate building both, so procrastinating) and electronics installation, the buggy is built. A few more lessons learned. While installing my Yeah Racing fan into the carbon fiber top plate, I thought the Yeah Racing fans would be sufficient. They are not. So, either pre thread the plate, get way stronger screws, or bore the holes out and get longer screws and nuts. Wasn't at all surprised, but figured I'd try. Also, I do wish it was a little easier to get the center diff out of the assembled buggy. From what I can tell, it's either a bit of a squeeze or more than just removing the top plate. Not the worst thing in the world, but would be nice. Maybe I'm just missing the trick to it.

Also realized a bone head move on my part. I knew that AE wheels needed +1mm hexes. I knew that I was getting wheels for the AE buggy. But my brain just didn't fully engage, and tell me to get different fitment or hexes. Oh well, I needed to order this 0.5mm shims for tuning anyways. Those are unreasonably hard to find.

Up next are the last few bits, painting the body and resigning myself to shock assembling and gluing tires.

 

[TBuggy]

I have the stock screws threaded directly into the carbon center plate and it has held up through many crashes and still looking fine. I didn't have to do anything special...didnt even thread the carbon ahead of time.

The trick with the center diff is to line up the slots on the outdrives so they are vertical. Pull the rear end of the diff out first and it slides out no problem. To put back just do this in reverse (front end in first). Once you realize the right position to have the diff cups when pulling it out, it is actually very easy and you don't have to force or pry anything. I will try to post some pics later.

What do you need the .5mm shims for..the hubs, arms?

 

[GMcThornbody]

I wasn't able to fully clear the support, even with the outdrive slots vertical, not without flexing the center support back. I'll just have to fuss with it some, I suppose.

The issue I ran into, at least with the screws that came with the fan, is that they're phillips head and the heads started stripping before fully screwing into the plate. Not at all surprised by that. Likely that mileage varies depending on what screws come with the fan.

For the shims, just general suspension tuning. Unless I haven't found them, there aren't any more than what's needed for stock setup in the box. Not mad about it, just wish I'd thought to order it with the buggy.

 

[TBuggy]

I didn't have time to take pics last night but found this video that explains the diff removal and shows the process.

 

[GMcThornbody]

Ah, I see! I was trying to slide it straight down. Thanks for that! I appreciate and (hopefully) other newbies to the chassis will.

 

[GMcThornbody]

Figured I'd toss up my untrimmed body.

 

[GMcThornbody]

First race day, folks! Worked some bugs out, for sure.

Learned that the ring/pinion mesh needs to be much tighter than I'd expect on an offroad buggy with no cover for the gears. Luckily, someone had a spare to sell me, and they helped me set it up. Way more snug than expected.

Apparently still didn't grease up the turnbuckles enough. I thought I had plenty and that after the initial threading they'd be good, but apparently not. Every single one popped off. I'd like to hear the more long in tooth guys experience. Do I just need to REALLY slop it on, or should I consider some captured ends?

More specific to my track, it was recommended that I take the steering bump stop screws out, that I'll want every bit of throw I can get. But there's not a single high speed corner at my local track, so your mileage may very.

Also learned that the stock wheel nuts have a fun balance in getting snug enough and stripping out, as both the left side ones popped off. I found one and went heavy with thread locker and it made it through the heats, but I don't trust it much, but the second is off in a field somewhere. Luckily a guy had a big ol' kit of random hardware and had a true locknut with nylon. Debating if I want to get stock replacements or actually get some nylon ringed locknuts and save myself the hassle. When I get fast enough that I'm to shaving weight, then maybe I'll reconsider.

Unrelated to the buggy, but found out that my old Spectrum radio hadn't survived the years as well as I thought. Found that it likes to glitch, so I guess a replacement is in order. Upside, the EB410 took straight lawn darting off the big air tabletop like a champ.