3Racing got bigger balls than Tamiya (ooooeerrr) I got big and little balls (no comments please)

Please help me before I start to lose my mind.:eh?:

Got a very frustrating problem with the Durga.

After two race meetings and 10 races started, I have failed to finish 6. One was due to me crashing and breaking a shock tower. One was caused by a connector shaking loose. But FOUR have been caused by the battery shaking itself apart at the battery bars.

I run 6-cells side-by-side, EP4200s with Much-More Premium bars.

I have tried glueing the cells together, taping the cells together, padding the battery tray out with foam, removing aforementioned padding. I have been using either a professional quality Weller 60W iron with a big tip or one of the 12V irons with a monster tip with Much-More 4% silver solder. And the packs are still breaking apart.

Next on my list of things to try is heatshrinking the whole pack together and using braid instead of bars to make the cell joints flexible.

Any other suggestions? I have never had this happen before expect for big crashes that have left the electronics hanging out of the side of the car, to have it happen so regularly now in normal race conditions is starting to spoil my fun.

Seems to me that the Durga chassis flexes a little more around the edges than you might think and the battery pack is taking the strain.

Anyone else having this problem? It would really help me to know I am not the only loony in the world who is suffering from this. :wtf:

I am running saddle packs - so I guess a lot less stresses involved. My pack does move around a bit in the car, do you find the same? I've not actually installed any foam though. I wonder is some sort of carbon fibre battery strap could solve your problem by stiffening things up a little bit?
I can't really see the chassis flexing enough to cause this - maybe it is, but I just can't see it. There ARE chassis' about that flex that much, but surely not the durga? :confused:

Did you scuff the ends of the cells a little with sandpaper or a dremel with a soft sanding whell before you soldered them? That usually helps with mine....

Try padding the bottom of the battery brace too. Might help by keeping the cells a little tighter with the padding underneath as well. I use foam sheets in 2mm from craft shops and stick them in with thin double sided tape. (you can colour-coordinate with hte foam as well ;))

don't scuff the cells.

If you are going to solder, use a small amount of flux on the cell before soldering. Thats how they should be done.

Chances are you have a mixture of a little cell vibration/movement and a slightly cold solder joint (not enough solder flow from the heat). Heatshrink will just compound the problem.

I get a little movement but not a lot, and it is tight around the motor mount. You could try turning the batt strap screws in a little more so the strap really clamps the cells, or put foam on the underside of the strap.

By scuff I really mean scuff not grind!

Proper solder has more than enough flux down the middle of it to get nice joints and the scuffing gives a better mechanical joint. Has always worked for me up to now and flux has always made a bit of a mess...

Im about to make an order on a couple parts at the moment. I am considering getting a back up "drive belt" . Can anyone suggest to me if this is nesacerry or not. Do the belts have a good life span or should i get one just in case for back up? Thanks.


A.J.

yeah get a spare belt. I've been through a couple of my 501X, one was from a stone getting in there (not a problem on the Durga) and the other was from running the front belt too tight.
You never know though - and it's worth being prepared.

Thanks for the advice Jimmy. Appreciated as always.

Diff Question
 

Is the 'Synthetic rubber cement' that is shown in the manual really the same stuff you get in a bike puncture repair kit? Also, I'm not sure about the 2 piece diff outdrive setup. I know it probably works OK in practice but it looks cheap and nasty - does anybody know if the 501X diff joints (TA-51286) or any other one piece part can be used instead? I am using Kanzen diff balls as I'd like to build the diffs as low-maintenance as possible.

Does any one have any idea what are those AW grease and the black grease that come with the durga kit for? seems like i didn't use any at all :confused: and how tight should the ball diff be for front and rear? thx

You should have used those greases. The thrust race should have either one in. The AW grease is for the driveshafts. I used AW grease to keep the pins in on the axles also.

Yes, the rubber cement is as used in puncture repair kits/trainer repair glue. Some debate over whether it is needed, I used a spot of superglue on them, some people just put a dab of ball diff silicone grease on the back of the plates, or you can leave them dry.

I always used to either leave them or put a dab of silicone grease on them, but the diff seemed to be slipping so I glued them this time.

Since then the diffs have been fine, they needed quite a bit of tightening after the first few runs bedded them in, but they didn't need attention at the last race meeting. I have a slipper clutch in now which no doubt helps take some of the strain off the diff.

I believe the 501X outdrives would be a direct replacement though, I might change to them if diff adjustment becomes an issue again.

Thanks Sosidge,

I'll get some new glue, that what I've got in an unopened puncture repair kit my nan bought me when I got my first 'big lads' bike might have matured a bit over the last 27 years!

Just priced up front and rear 501X outdrives and at $14.40 a pair plus postage from HK I am undecided whether to go this far yet, or just so how it goes. I will be running an LRP Vector X-11 7.5T brushless motor in it.

It'll either hang together or shred itself to pieces I suppose.

On the topic of the slipper clutch...

Tamiyas suggested setting is 3mm. I think this is too soft, and I was struggling for punch and braking. After bedding it in over a few packs 4mm seems to be better. This is using a 12-turn motor.

That's the way I always run things! If it breaks, upgrade, if it doesn't, leave well alone!:D

Brushed or brushless?

Brushed.

You are a wise man. I should have had you sitting on my shoulder over the last few weeks, I think with what I've spent on hop-ups on an unbuilt car (!) I could have imported a B44 for the same money. I just keep consoling myself that the main reason I bought the DB01 was so I can use my Trakpower lipo.

Another quick tip on fitting the slipper.

Put the 3 remaining 4x0.2mm shims from the original layshaft on the pulley side of the slipper layshaft to take out the slack.

Otherwise the layshaft moves around a lot, I noticed that the belt had been slapping against the slipper plate leaving black marks, may not be ideal for belt life.

reluctant to post too much in case it becomes obvious that the last car I ran was a semi broken Avante... anyway I spotted this and thought someone would find it useful..

http://cgi.ebay.com/3Racing-Aluminum...QQcmdZViewItem

whilst I'm typing... is there anywhere that all the useful info you guys are posting re the build and recommended spares and upgrades has been summarised and laid out in one go, like a oOple Durga FAQ ??

SJ

I was wondering from any of you guys who have already installed the front one way, if one half of the diff sits lower than the other while installed? I know that i have the black sleeves with the arrows properly adjusted, but one side is sitting lower than the other. Im not sure if with the box cover on and the dog bone pushing into the joint if it will even things out. This just doesnt seem right.

check both holders are orientate the same, the bearing holder and the holders carrier. It can't be lopsided if mounte right.

Never mind guys. I guess i was wrong when i said i had the sleeves assembled correctly. Just a little mishap while transfering from the stock to the one way, but now all is good.:) I spoke too soon.


A.J.

Hello again all,

Finally got the new radio set (acoms 2.4gh cheap but hopefully cheerful) and so she is up and running. Scary fast with the Mamba 6900!!!
Only done a bit of bashing as waiting to sort out KKC membership but impressed so far.
One small problem though. The acoms servos are a bit weedy I thinkand are operating at their limit so I am after recommendations for a good steering servo. Nothing spectacularly expensive as my skill level does not warrant it. But sommit that will be ok for club racing.

Cheers

I have aBluebird 617 MG in my DB and its wicked fast and torquey too, think it was only £30 shipped from Japan!

lee

where from ralphee

Umm it was off an Ebay seller buddy, hang ten ill see if i have his details buddy!

lee

Wayne

Just type in 617MG in the Ebay search, itll bring up the seller and the servo buddy my bad its HK not Japan, id link it but im not sure on Jimmy's Ebay link policy, i really should read more lol.

lee

cheers mate,
will have a butchers if I can fool my works goddamned firewall into letting me view ebay!

I have the Bluebird 631. They are excelent servo's. I think it was dinball I got mine from on Ebay about the £35 ish. I cant remember the postage though as I combined with my pal to order a few things at once to save costs.

Just found a bluebird BMs 620 MG for £25 and it's just up the road.

Will this do? 10.6 K torque 0.13sec 6v?

Any advice appreciated

it is a little slow, but definately up to the job of steering.

631MG is the way to go as you say drinternat its metal geared too, speed .08sec and yes it was dinball we got them from, they were £35.00 including p&p to UK.
Excellent servos, for which you can get all the parts for, if you can break them, even Jimmy uses them so can't be bad. Ha Ha

Thanks for all the advice on the bluebird stuff. However,being an impatient tw!t Im going down to antics in worcs this aft to see what they can offer me. Thought I would try and support my local shop a bit!
Don't think they do bluebird stuff though.
Does anyone have any recommended alternatives (futaba or hitec) or is the bluebird stuff so good I should park it and wait???

Cheers

Or a 661MG+HS? found at another local shop?

Ye I realise I am being a complete PITA!

I would totally recommend Futaba.

Hitec and Bluebird are two servo brands that I definitely would NOT recommend as I have seen problems with both first hand in terms of quality, fit and performance.

Also Tamiya do not supply servo horns for Hitec so that may cause hassle, you might have to bodge something together with Hitecs own part.

Unfortunately Futaba do not make a fast, mid-priced servo (eg £35 ish), you need to go towards £70 to get a fast Futaba new. My cars either have Futaba 3003 (£8) or 9451/9550 (£70) in them!

However you will notice that the other top-top servo brands, KO and Sanwa, don't make fast mid-priced servos either. There is probably a reason for this...;)

Bit of a price swing there sosidge!
Your comments have reminded me of sommit as well. Which of the supplied servo horns fit bluebird servos? (If I went that way?)

Still not decided yet. £70 for a part time racing/bashing servo seems a mite excessive to me.

The Bluebirds fit a Futaba horn.

The Acoms will probably prove to be fine for bashing, I would run it until it breaks, but you will find that the quality of a basic Futaba is a step up although not necessarily a great deal faster or torquier.

Futaba do do a metal gear servo that is a shade faster and torquier than a standard one for £20, called the S3010, personally speaking that would be the limit I would go to unless I wanted to spend £70!

I have used the S3003 in touring and buggy before, in touring it is fine, in buggy is is maybe a little bit weak for racing, probably fine for bashing. Futaba also do the S3004 which is a ballraced version of the S3003 so should be a little faster and smoother and last longer without wear.

This is just my recommendation of course, I am sure you will find plenty of people who will sing the praises of Bluebird, bit I wouldn't touch them with a bargepole!