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Tamiya DF-03 type

Tamiya DF-03 type

Old 03-26-2009, 10:31 PM
  #496  
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Well, it's not that the shocks are too soft, it's directly related to oil and piston hole size as well as the number of holes in the pistons. The Tamiya piston holes in the DF-03 kits are just too darn big. I know that some people just used different shocks on their to get smaller holed pistons (such as the AE, I'm planning to put the Losi ones on)...

I have mine setup with 55 wt oil all around withe the one-hole BLACK pistons (the with a slight knotch on one end of the circle to let more oil pass through, not the white nylon stuff in the "MS" portion of the MS kit), it was too stiff for my taste. If you're racing on a super-smooth track, the 55 might work well, but check out a few posts above on my theory of why I keep breaking my parts from the A-Parts tree...

I think the 55wt with the one-hole piston is just too stiff and there's too much pack in the shock. With too much pack, the shock absorbers are not longer arbsorbing.

I'm not sure what kind of track condition you are running in, but it's probably safer to say that try the car with a 45 or a 40 wt AE or Losi oil (I've yet to use Tamiya oils since I'm unfamiliar with Tamiya's weight system of their shock oil).

I just bought some bushing for my Losi shocks so will keep you guys posted when I mount these things on my DF-03MS and how the perform. I'm looking forward to them since I'm pretty familiar with AE and Losi shocks...


mj, you should go download the Dark Impact manual, if you don't have an MS manual already. The ball studs on the front knuckles are supposed to be on the bottom. The 4600kV is a wonderful little motor and I think it's perfect for 4-wheeling. My 5700kV in my B44 had to be toned down via software because it was just too much motor for that poor buggy...

I think the MM and the 4600kV fed by the SMC LiPos, your DF-03 is probably a rocket! My only gripe with these powerful brushless system is that I go through tires like crazy nowadays!!!

I read that you stripped your spur, remember to torque the heck out of the motor screw and even go as far as dabbing a bit of blue Loctite on the threads of those motor screws. I'm not sure if you're still using the 0.5 pitch system, but I've long ditched those and used AE spurs with 48 pitch Robinson pinions. Robinsons are cheap and effective, not the best pinions in the world, but they work... Just use a body reamer on the AE spurs. I know you probably already know, but do the paper trick for the meshing in between. My mesh is as tight as it should be, where if I hold the pinion, the spur just rocks ever so slightly...


On a side note, I ended up mashing up the thrust bearing in the diff assembly. I knew that the thrust bearings are a goner since I struggled to get them out of the diff half, and the face of the washer face of the thrust bearing looked a little deformed (probably why it was jammed).

I bought some 2mmx5mm washers and 2mm steel balls to make my own thrust bearings. Will keep you guys posted on that as well for the progress. The diameter of inside the outdrive is 6mm, so a 5mm washer with 2mm steel balls SHOULD work, since diff screw takes up 2mm (it's an M2 shoulder screw, although I have a hard time finding an M2 that is 25mm in length) with the OD being 6mm, that leaves 4mm of diameter difference. Dividing the 4mm in half (since the steel balls need to be on all sides of the screw, that gives me a solution of 2mm steel balls for the self-made thrust bearings.

What really drove me to do this? Thrust bearings are $14 from Tamiya!!! That is just too much for my taste. Steel balls are about $7 bucks and $2 for the washer from McMasterCarr, and I can probably make 20 sets of thrust with those...

I know that you can get some Stainless Steel screw set from RC Screwz, but again, I hit up McMasterCarr for my hardware needs and ended up getting each size that I need for $6 bucks for a pack of 100.

McMasterCarr has one of the most intuitive web applet for finding hardware, you guys should give them a shot, they are a huge house that stocks a ton of machining materials and general goodies... Their paper catalogues are like a BIBLE of the machining world in my opinion, since they also explain material difference in laymen's term...
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Old 03-27-2009, 11:46 AM
  #497  
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i will make sure to torque those bolts down a lot now. and use the blue locktite. def needs that. i was thinking about getting lock washers, but that might be over kill.

i replaces the front with 45 wt oil, but will be testing that wednesday. hope it works out. and now that the camber is all adjusted it should drive better too.

i had a b44 spur but the other guy who sold this too me had reemed the hole a bit off. so when i tried to reem it, it got WAY off. it wobbles like a flat tire going 80mph now. !!

ive got the manual, printed, original, and pdf form. there are 3 bottom holes, which one? i have front and rear in the middle hole.

i like the power for sure. cant really complain at all. the tires should last me a while because the track is pretty soft in most places when its wet, it gets really hard when its dry, but its red clay, so its not really grippy.

i actually have a ceramic thrust bearing from some company, but have to get the diff rebuilt to get it in there. i might have to drill the head off the bolt so i can take it apart and salvage the necessary pieces to make a real ball diff, and not a locked one.
if you are getting some diff bolts from mcmaster, i can go in on it with you and split the costs!
i went to mcmaster and the site is very easy to find bolts.
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Old 03-28-2009, 01:57 AM
  #498  
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mj, unfortunately, I couldn't find any m2 screws that were 25mm long (which is what the diff bolt is). I'm gonna look around other hardware stores, but this length is probably quite unique and would probably be hard to find since m2 screws are quite small and a long bolt is hard to find since you would usually go up in the screw size to go longer for strength...

I'll keep you posted if I come across any. If not, I might have to order it from Tamiya directly. I'm waiting for the them to restock the chassis soon, I'll probably order it with that order... I hope they get them in there SOON because that darn coupon that you get for filling out the survey is only good for 30 days... arg, had I known about this, I would've put the survey off until they restocked their chassis.

Tamiya support is pretty good, I'm probably just gonna email them and ask them for a rough estimate on the ETA of these wonderful chassis...
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Old 03-28-2009, 11:48 AM
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i am going to see about getting a whole diff assembly, i really dont want to take a drill press to the diff to take the bolt out, but if i have to. well its gotta be done.\

until then i will be running with a locked rear diff.

i am also going to have to re gear my whole chassis, and get some new gearing going.

i waw thinking of stepping up to the 84t spur, but they are both kawada style, which takes the small little white delrin pins to insert in the little holes, i am missing two of those, you think it would still work out?
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Old 03-28-2009, 03:40 PM
  #500  
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A little update on my diff assembly. My order came in from McMaster yesterday, which included the 2mm steel balls and the M2 washers (0.25mm thick was the only kind they had).

The washers were definitely too thin for a thrust assembly, since other thrust assemblies that uses this scheme like on the Associated diffs, uses these really thick washers.

So the solution was just to double on the washer. Four washers per thrust bearing with 6 steel balls. The OD of the washer is actually 5mm and not 6mm but the 0.5mm difference in the radius didn't make that much of a difference.

After I built up the thrust assembly, I proceeded to check to make sure there was a thrust-bearing action going on. Which is the diff bolt head should never turn independently of the diff nut on the other side. It should always follow the nut (which indicates that the bolt head is not backing out and that the bolt head is rotating freely on the thrust bearing assembly).

The diff is super smooth. I've read many things about diff assembly and one of the achilles heel has always been the thrust bearing. With 6 new steel balls and four washer (2 on top and 2 on the bottom sandwiching the steel balls), the diff action is super smooth without it loosening up.

My plastic transformation is nearly complete. I've also pulled out the center one-way out of the rear gear box and just put in a regular crown gear with an additional aluminum drive cup (just like the one that comes with the MS kit for the front), so both my drive cups front and rear uses the Tamiya aluminum.


One thing to note. The 3Racing Steel HD outdrives were really shot. The hardened portion of their name really is a false advertisement. Their steel is super soft and m experience with these Steel HD (gone through two sets already) are that they are using inferior material (big surprise right? The metal is from China).

Luckily, I bought some good Tamiya stuff (Japanese steel! ) way back when so I replaced it with those. My front and rear outdrive both uses the Tamiya's steel outdrive. Even though Tamiya only calls these out for the fronts, they are identical to the rears so you can buy the "fronts" and use them in the rear.
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Old 03-29-2009, 02:46 PM
  #501  
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So your thrust bearigns make everything hold up a little bit better and are cheaper than Tamiya ones huh? Sounds like I can finally rebuild my diffs...

And you say that the steel "front" outdrives for the DF can be used on the rear too? Are they a lot stronger than the stock outdrives?
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Old 03-29-2009, 03:08 PM
  #502  
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Yeah, the thrust bearings hold up a lot better. One of the problem with Tamiya's caged thrust bearing was that the bolt head tended to concentrate on the center cylinder of the thrust bearing rather then on the face of it (if that makes any sense? Sorry for such a poor explanation).

As for the outdrives, there is no difference between the front and rear, except one of them uses a partial plastic (the diff plate portion) partial steel (the outdrive portion) construction while the other is all steel...

I've already gone through two sets of the 3Racing one, being so cheap, I figure I can save the stock one if these failed, which they did. My first set snapped where the outdrive meet the dogbone, the second set, where the dog bone meet the outdrive, it was so worn out. I had a set of original Tamiya Steel outdrive on the front which has similar mileage on them and they don't show any wear or tear. So my conclusion about the 3Racing outdrives are that they are all-show but no-go. Their steel is truly an inferior type of steel and should only be used in a pinch. The Tamiya's steel outdrive is definitely really good stuff, same quality as the stuff you get from Associated and other manufacturers...
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Old 03-29-2009, 03:44 PM
  #503  
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So I decided I was goign to look on towerhobbies to try to find parts to do my diffs from scratch and make my own thrust bearings like you did tom. Here is everythign I found and if its all right I can rebuild both diffs for only $15! Lemme know if all of this would work and if I am missing anything. Thanks man.

2mm diff balls(use them in thrust bearing?) - http://www3.towerhobbies.com/cgi-bin...?&I=LXKPB9&P=7

M2x25mm diff screws from HPI - http://www3.towerhobbies.com/cgi-bin...?&I=LXM489&P=7

M2 Washers - http://www3.towerhobbies.com/cgi-bin...?&I=LXVTH5&P=7

And finally, two sets of 3mm scalpel diff balls - http://www3.towerhobbies.com/cgi-bin...?&I=LXRHZ8&P=7

Is there anythign I'm missing or don't need? If I could rebuild everything this cheap that would be amazing. I alread yhave the gears themselves. Thanks man. Oh and what gearing are you using with your 4600 motor? Thanks again
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Old 03-29-2009, 04:54 PM
  #504  
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All of those items seem to be ok except for the 2x25mm screw. it might work, it might not, since the shoulder portion of the screw to the threaded part seems to be in different proportions...

It might be worth a try but you might have to fall back on the stock diff screw...

All the other stuff seems to be in order. You're missing the diff rings, but you can always flip it over to the other side and use the shiny new side, if you've already done that, you can always lightly sand it and get a few more uses out of them
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Old 03-29-2009, 05:11 PM
  #505  
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I already have new ones. I ordered some stuff a while ago but never got the diff balls or bearings... Not sure if I need new outdrives though(likely do...)
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Old 03-31-2009, 08:55 AM
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Default DF-03 differential uprated

Hi everyone, this is my first post on this forum and I would like to acknowledge how good it is to start with and a big thankyou to everyone and the general rc knowledge that is available-it has helped me a lot.

I'm posting in this thread as I own a df-03 with the obvious 'hop-ups' including slipper, ballbearings, carbon chassis, brushless, shocks....

I have however had massive problems with the rear differential and it ability to withstand varying brushless motors and until recently melted three of them in an effort to get the df raceworthy. No amount of adjustment to the slipper and/or the diff made much of a difference and eventually it would always overheat and eventually melt.

I read around the forums and after hearing that others usually had the same problem I decided to forget buying more bags of gears and usually at stupid prices. I got a mate to machine a decent differential unit instead of the rubbish stock nylon diff, I've attached some pics of the new diff next to a stock for comparison.

I've not managed to test it just yet but the diff has been reassembled and sitting back in the car waiting for a good ripping later. As soon as I've put a couple of Lipos through it I'll report back.Tamiya DF-03 type-diffv1.jpg

Tamiya DF-03 type-diffv2.jpg
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Old 03-31-2009, 09:31 PM
  #507  
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blackcat, first of all, welcome to the DF-03 thread. The center diff area plate that your friend machined for you definitely looks very curious. How is that held on there without slipping? Is it held on by those two screws?

One thing to check is to see if your diff bolt is backing out of the diff nut (the nut inside the T-sleeve). Are you getting lots of diff slipping after a few runs?

One of the causes maybe that your thrust bearings are shot. Your thrust bearing helps prevent the diff bolt from backing out by isolating it from the diff outdrive.

I've yet to melt one of the spurs but you must've gone through quite a bit to have your buddy machine one out for you. Keep us posted on how well it works for you!
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Old 03-31-2009, 09:35 PM
  #508  
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Thats pretty interesting... And I am going to be ordering parts to rebuild my diffs soon I think. Does anyone know where I can get outdrives? Tower doesnt have them and I dont know where else in the USA to get them... Thanks
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Old 04-01-2009, 01:28 AM
  #509  
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The only place in the US that I've found to get the real Tamiya outdrives is unfortunately, off of tamiyausa.com website.

If anyone knows other places to get outdrives, I would definitely be interested to know. MSRP of parts (not full RC kits) are usually a few dollars off from retail, but when mail ordering, that difference can pay for shipping usually.

But if you need it quick and need to run your car, what's a few dollars (at least that's what I tell myself )?
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Old 04-01-2009, 02:20 AM
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Originally Posted by K10wN View Post
Does the RW Layshaft have a steel or alloy main gear? Where can you get them from if they are steel?
It was a company (guy?) out in England that custom made them. I don't think he does it anymore.

I don't know if it's aluminum or steel, but am leaning toward the latter.

Last edited by encore75; 04-01-2009 at 02:35 AM.
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