E-MAXX 3908 Brushless

[bentrocker]

Took my esc apart the other day and cleaned it out. Wow was it ever full of debris. I believe the fan is totally shot now. Makes some very strange noises when I turn it on. This is from having the rock stuck in the fan. Emailed castle over a week ago and haven't heard anything back yet. I am just going to buy another fan and case. The only thing I am worried about is that the thermostat may have been damaged.

[ArmyofDarkness]

Save your money- you can get better quality replacement fans very easily ( the castle ones are known to fail easily.. apart from my one that is... ); just measure the size and thickness ( 30mm x 5mm I think, but check ) and check ebay/ radioshack etc for a 5-6v replacement. You'll have to recycle the old fans connector, but that's easy enough to cut off & solder on to the new fan.

Just make sure you use some form of filter mesh/ material around the esc to keep out the crud- old tights work great, especially black or sheer ones as they don't stand out so much.

This is a good thread to read:

Making your fans bulletproof

[bentrocker]

Thanks man , never thought of that.
Great link.

[Suteki]

Got my shims today so it's going to be time to pull the car down and shim it all up. Still waiting on my new differential or differential ring gear, which ever turns up first. Thats the thing about hobbies like this in Aus, because we are so small a market it's hard to buy stuff off the shelf unless it's a really popular part or upgrade, you have to order it in. Really annoying.

Painted my new body today...looks absolutely awesome. Did a test with the LED's to give me an idea how it'll turn out as well. If all goes to plan this thing will look brilliant. Was going to take a picture but I think I'll leave it till I put the whole lot back together.

[bentrocker]

Sound good, just waiting for a pic.

[Suteki]

Haha i cant wait to actually get it all back together. I havent taken the car out for some time because its all pulled down. Will bedifferent when its back together.

New rims and tires, new body, new bulks and shock towers, lighting.

See plenty of cars with leds but only ever seen one kind of lit the way i am going for, so provided i can. Get it right the effect should be fairly unique.

[bentrocker]

Just bought some tekno axle carriers going to give them a try.

[Suteki]

Im still waiting on a differential, its taking ages to come in. None in aus that i now of snd the ebay one from us was ordered around mid to late septemer.....

Painted my body and tomorrow should have light kit fit, will get a quick vid of it.

[bentrocker]

I heard back from castle today about my fan issue. They want me to buy one from them that is out of stock. Glad I picked one up on eBay last week.

[Suteki]

Finished up the LED's for my body this evening, so again, the only thing holding me back is waiting on a differential. Have no received my diff for the 3908 from eBay seller at this point, not sure if it's just taking a long time to arrive or seller is a bit on the dodge side. Wasn't expensive, just inconvenient more than anything. Still hoping it turns up but my order I placed maybe a week and a half or two weeks after with Tower Hobbies arrived today from the US also.

Speaking of which, my Slash 1/16 VXL arrived. Tomorrow I am doing to do a little video I'll upload of how the body and the LED's turned out. Really happy, came out better than expected. Wasn't hard to do, just paranoid now I'll smash up the body Also had 2 head lights left (kit came with 4 whites for headlights, only wanted 2 so I had 2 left over) so with some quick soldering, I had some head lights for the Slash VXL. Hehe.

Have to say, if anyone here even has half a thought of getting a 1/16 Slash VXL, don't hesitate. I Drove it around through 3 lipo's worth today (only tiny little 2s 2200mah batteries) and I had a blast. The cars are just plain fun, bought it for a giggle and certainly got it. Will also post a little video of my thoughts on it when I make a video on the Emaxx body. I don't normally ever make videos so they'll be rough but gives me something to do at night I suppose. So should do them tomorrow.

[bentrocker]

Well I am going to open the esc to instal my new fan. I am considering plastic dipping the esc for winter. Is there any downside to doing this other than voiding the warranty?

[bentrocker]

Went ahead and plasti dipped my esc getting it ready for some winter bashing.



Here is the dip.

Not real worried about it being water proof just splash resistant. Will be driving in alot of soft snow.

Took some pics of some of the debris that was in the heatsink.

[bentrocker]

Instaled tekno carriers yesterday. Looks like they are going to work with the lst cvds.


This where I set the ball studs so the dogbones wouldn't bind in the drive cups.

Lower

Upper

I have also had a problem with the screws pulling out of the rpm lower arms. After hard landing but had it happen in bad tumbles. I don't know if you can do this on stock axles.

Instaling the nut can be a pain , but it is better than it pulling out in a bash session.
Also made a crude set of mud flaps out of rubber.

[Suteki]

What differential are you using? Standad with xxl out put cups going to xxl cvds?

[bentrocker]

I am still running 3908 diffs with traxxas drive cups.

[Suteki]

Got my Traxxas steel driveshafts from the transmission today. Very impressed with them, very weighty, solid, smooth action to them. Was a pretty easy install. Took the car out for a spin. Having played with these drive shafts, I'm tempted to replace all of them to this part. They make the standard plastic ones feel like utter junk.

[bentrocker]

When I went to the traxxas drive shafts it made a huge difference. No more broken rear shafts.

[Suteki]

Great to hear. Unless they bend or break i wont know if its an improvement but judging by the sheer weight of them, they must surely be better than the plastics. The plastic drive shafts already show plenty of small marks where grass has gotten caught and worn into them, the cvd on my center driveshaft that broke was just ragged, not surprised it went after seeing it. Cant see that being a problem on the steel ones.

[bentrocker]

Changed up the body I was running. Used shoe goo to stick the HPI blower on. It came off a friends charger body. Not expecting it to last long.
Also replaced the traxxas radio withe a spektrum dx3e I had and bumped the voltage up to 7.0 volts to the servo.

[bentrocker]

Have been very happy with the cvds, only managed to bend one in a bad wreck. I also added some panty hose on top of my esc to keep little rocks out, since I messed up my last fan. It also messed up my esc. Sice I put the new fan on when the esc gets hot the fan won't come on unless I turn the esc off and on.

In this pic you can see the red and black wire, that is running from the fan to the reciver direct now so the fan is always on.

Also changed the center drive cups. The ones that came with the flm chassis are starting to wear pretty good. I replaced them with the traxxas extended drive cups.

The top ones are the traxxas extended drive cups, middle flm and the bottom are the regular traxxas drive cups. I have been using the bottom one for the axles.

[GaiginRC]

Well I am going to open the esc to instal my new fan. I am considering plastic dipping the esc for winter. Is there any downside to doing this other than voiding the warranty?

I ran across your post and saw the pics of your ESC. As a CC Repair Tech, I'm not sure if that would void the warranty since I've seen all kinds of weird stuff being sent in for repair. As the guy who would actually be reapring this if it's ever sent in, the plastic dip would make my job a pain. As a fell EMBE owner, kudos for weather proofing!

[bentrocker]

Thanks for the reply.
If I sent it in I would clean all the plasti dip off.
I love the esc just bothers me a bit that it won't automatically start the fan when it gets hot. It was doing this before I plasti dipped it.
I must have damaged the thermostat or what ever it is that starts the fan when the rock got stuck in my old fan when running 6s.

[Popoxx]

Also changed the center drive cups. The ones that came with the flm chassis are starting to wear pretty good. I replaced them with the traxxas extended drive cups.

Traxxas center drive cups aren't sturdier than the FLM one's unfortunately, I recommend you HPI cups (ref 86276 with 86094), the best I tried :

[bentrocker]

Thanks Popoxx
I only used the traxxas ones because that is what I had at the time. I will check out the hpi drive cups. I was looking at the ones from rc monster but I am sure the hpi ones are cheaper to pick up.
On a side note I studied you maxx build quite a bit before I put mine together.

[F34RL355]

hey guys, nice thread u got going here lots of good info, thought i would sign up on here and join in, i bought an emaxx 3908 not too long ago and have been doing some upgrades,

flm bulkheads f/r
rpm shock towers f/r
rpm bulkhead braces f/r
rpm arms
rpm true track
traxxas center cvd
tbone bumpers with wheelie combo f/r

its pretty bullet proof i just cant keep the boddy from ripping off! bad landings and such just destroy the thing :/ any advice on a better clip or something?

what else should i do to the emaxx? i want to bash it without it breaking, i think i have that down, but i think i could use something in the shock department.... not sure what to get, i dont wanna go to flm shock towers,i like the flex of the rpm, but i hear without them it eliminates alot of ur options? the stockers are okay, i havent had any problems with leaks or blowing cap,s the shafts are flimsy, which is good and bad, cause i can just bend them back with my hand lol. and my rig still bottoms out, was thinking of using thicker oil.

anyways enough rant for first post ill upload some pics later

[F34RL355]

Traxxas center drive cups aren't sturdier than the FLM one's unfortunately, I recommend you HPI cups (ref 86276 with 86094), the best I tried :

can u use those on the diff side? my traxxas cvd cups look worn on the diff side wondering if i should grab these, they look the like they would work

[Popoxx]

can u use those on the diff side? my traxxas cvd cups look worn on the diff side wondering if i should grab these, they look the like they would work

I think it should work too but I can't check.
For body clips, you can use HPI ones (ref 6203) or Dubro ones (ref 2245).

Don't hesitate to start your own build thread

[bentrocker]

I was getting tired of replacing my bell cranks every second run and hitting my truck with a merv and breaking it was the last straw.
I instaled a GH Racing bellcrank.

Assembly was a breeze


I did have to do some shim work to the tierod. 3 shims per side.

Instaled

[c0nr4d]

bentrocker
have you tried using the maximizer beadlocks with the BLs? Do they fit? Thanks man
Con

[smplgy65]

I see you are using the black spring. I also use the GH bell crank but I installed the silver spring, it says it's not a firm as the black, and on my first run I stripped both servos. I also had to shim it and it worked great on the bench but not to thrilled with the servo saver.

[bentrocker]

bentrocker
have you tried using the maximizer beadlocks with the BLs? Do they fit? Thanks man
Con

The badlands I have are 3.8 traxxas bead. They won't work on the maximizer , they are 3.2.

[c0nr4d]

The badlands I have are 3.8 traxxas bead. They won't work on the maximizer , they are 3.2.

Alright cool. Thanks man. Sweet max btw!

[Razmo]

Went ahead and plasti dipped my esc getting it ready for some winter bashing.



Here is the dip.

Not real worried about it being water proof just splash resistant. Will be driving in alot of soft snow.

Took some pics of some of the debris that was in the heatsink.

Hey Bentrocker,

I would try dipping the ESC in "Silicone Conformal Coating". It's a flexible coating for printed circuit boards for resistance against moisture, corrosion and thermal shock. It's leaves a very thin coating also.

See www.mgchemicals.com



Raz

[bentrocker]

So far the only problem I have had with my 3908 diffs that are shimmed, is bearing failure. The inner pinion bearing keeps flying apart. I have replaced the inner bearing with an avid that has double steel sheilds. Might help.


I picked up a used castle 2200kv motor the other day. Put it in the maxx to see how it works. Bought it for another project.

The other project. Building a brushless E Slayer.

The t-bone doesn't like cold days and rocks. Haven't found a plastic part that has..

This is how my Geodes are looking. All four are out of round like this.

I bought this temp gun on ebay . It works great!

[GaiginRC]

I had the same problem with my T-bone skid plate. I emailed the company and they promptly send a replacement. This last summer my diff ate its pinion bearing too. After I cleaned up the debris it worked long enough until the replacement parts came in. How are the sealed bearings working? I got tired to constantly cleaning the bearings in the axle carriers so I replaced the Traxxas bearings with sealed ones. Has anyone else tried this?

[bentrocker]

I am running avid bearings in the axle carriers. Rubber sealed on one side and steel on the other. I have had good luck with those so far.
I already bought a new T-bone just waiting for the weather to warm up before I instal it.

[bentrocker]

Changed the drive end bearings on my 2200's today. Put in ceramics from boca

When I removed the end bell it pulled some of the coating off the wires, so I used some plasti dip to fix it.


Used a little blue loc tite to hold the bearing in.

Both motors are running ceramic bearings on the drive end.

[bentrocker]

Managed to snap the rear output on my 3908 trans yesterday. 6s paddle tires on the rear.

[Maxx Attax]

sick vid. your truck is stupid fast!

[MAYHEM6969]

I found those losi shocks what does it take to install those on stock shock towers or do you need the RPM'S or FASTLANES? thanks