Dt03 shock oil?

[borderlord 8]

Hi Cy, need some help.

DF springs finally turned up so I dived into the rebuild. Pulled the top wishbones and hubs off, went to fit your new uprights, and realised the drive hubs would not fit (miles too big). I'm still using the plastic hubs that came with the kit, but I assume you used metal drive hubs on yours. Would you have a part number to hand?
Since I have already bought the metal dogbones, hope you're not going to tell me you used universals.

Here's hoping

Jeff

[ThunderDragonCy 7885]

42 minutes ago, borderlord said:

Hi Cy, need some help.

DF springs finally turned up so I dived into the rebuild. Pulled the top wishbones and hubs off, went to fit your new uprights, and realised the drive hubs would not fit (miles too big). I'm still using the plastic hubs that came with the kit, but I assume you used metal drive hubs on yours. Would you have a part number to hand?
Since I have already bought the metal dogbones, hope you're not going to tell me you used universals.

Here's hoping

Jeff

Jeff, not a problem. You don't need universals at all. You need Tamiy a 50823. Just a few quid on eBay

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F253480378705

[borderlord 8]

Thanks Cy, that's a relief. Had visions of needing universals.

However another question has reared its head. I have the metal dogbones, so they don't fit the diff cups either. Would I need to replace those with metal too?

Sorry for all the questions. I had wanted to keep the buggy mobile until I had all the parts to hand, so I didn't notice these mismatches until I took the car apart.

Jeff

[borderlord 8]

Hi again Cy

Back to diff cups. I've found 9804237:

https://www.ebay.co.uk/itm/Tamiya-9804237-19804237-9804284-Gear-Box-Joint-2-Pcs-M05-M06-MF-01x-TNS-NEW/292683278196?hash=item4425486774:g:vxoAAOSwDuJWvgXf

Are these the ones I need?

Jeff

[ThunderDragonCy 7885]

8 hours ago, borderlord said:

Hi again Cy

Back to diff cups. I've found 9804237:

https://www.ebay.co.uk/itm/Tamiya-9804237-19804237-9804284-Gear-Box-Joint-2-Pcs-M05-M06-MF-01x-TNS-NEW/292683278196?hash=item4425486774:g:vxoAAOSwDuJWvgXf

Are these the ones I need?

Jeff

That's exactly right Jeff. I know it seems a pain getting all these extra parts but they do make a marked improvement to the back end of the 03.

[borderlord 8]

Hi Cy, thanks

Actually it's not the extra bits that are a pain. None of them is particularly expensive and they all represent a step up in performance.

It's just the time waiting for them to arrive. I really don't do 'patience'.

Luckily I managed to find UK suppliers for the extra bits, and they're here now, so the DT03 is back on the bench.

Let's hope I haven't missed anything else.

Talking about these things getting out of shape. When I did the original re-build I re-greased the diff, but I used some fluid I had for my Stadium Truck, which was only 7000 cst.

When I took things apart this time, I found most of this had ended up in the gearbox, and there was also a mix of grease and gravel all round the gearbox mount.

Picked up a tip from you about using much thicker grease, but also from here:

https://www.thercracer.com/2014/03/tamiya-dt03-neo-fighter-buggy-build-and.html

to which end I have some 500,000 cst coming.

Here we go again

Jeff

[Grotty Otty 868]

2 hours ago, borderlord said:

When I took things apart this time, I found most of this had ended up in the gearbox, and there was also a mix of grease and gravel all round the gearbox mount

Most diffs that require oil (even 500000 cst) normally have a gasket to prevent the contents spuing out into the gearbox. Try using a pea sized dollop of Tamiya AW grease instead. It'll have the same effect and not go anywhere. 

[Juggular 4964]

That got me curious...

Has anybody tried 500,000 cst?  Tamiya AW is a whole world better than the regular grease, but not thick enough for my taste.  I prefer "almost locking."  I use the 'clay' type in contained diffs (not sealed).  To my surprise, the diff can still turn just fine even on a slick pane of glass.  That's the best of both worlds; the diff works, and it also gives ample one-legged-propulsion.  I wonder how thick is the half-million cst in comparison.  The putty couldn't come out of a bottle, so 'somewhere' between the putty and AW, but where?  

This was a bit too much even for Konghead.  I had to take out some to make it 'almost locked.'  Also, the putty has to be kept clean, it does not like other grease.  Would 500,000 be more convenient?

 

 

[borderlord 8]

Hi Guys

Grotty

It would be handy if anyone knew the viscosity of AW grease. Google search revealed nothing.

By the way, isn't all grease 'anti wear'?

I first re-filled my diff with 7000 cst, didn't take long for it to end up in the gearbox and all over the chassis as well, hence the change.

In his Grasshopper thread Cy recommended  300,000 for the diff, and I found this:

https://www.thercracer.com/2013/10/tamiya-dt02-guide-mods-tuning-and-tips.html

which recommends 500,000.

Two  opinions from people who should know, good enough for me.

Juggular

Got some Associated 500,000 on the way, should be here in a couple of days. I'll see if I can find a way to demonstrate the 'stickiness'.

Bear in mind that 1,000,000 is now available:

https://www.ebay.co.uk/itm/Team-Associated-Silicone-Diff-Oil-Fluid-1-000-1-000-000CPS-Multi-Listing-/172749304025

Should be even thicker.

We'll see

Jeff

[ThunderDragonCy 7885]

Even the 300000k grease found it's way out eventually, although more slowly and think so easy to clean up. 500k might be better being thicker.

[borderlord 8]

Hi Cy

1,000,000 might be even better, but there's a snag. As I understand it, the thicker the grease the more it makes the diff act like a lsd.

Might be a balance needs striking here, between ease of cleaning and how the car behaves on the track. Another one for the born tinkerer. Over to you

Jeff

[Grotty Otty 868]

13 hours ago, borderlord said:

It would be handy if anyone knew the viscosity of AW grease

It's weird any info on the chemical composition or viscosity of the AW grease appears to be in a black hole and non existant! 

That's a really good link, I noticed that the RC Racer also used Green Slime after the diff was filled with oil, maybe this acts as a sort of gasket to keep the oil in? My only other suggestion would be to fill the diff, close it up and then apply a little auto silicone carefully into the gap around the round side plate. Once it's dried cut it flush to the diff with scalpel knife to create a custom seal. 

For reference my Cat K2 has 12,000 cst oil in them and the AW grease appears to be at least twice as thick as that! In terms of feel though (holding and turning the wheels by hand) my DT-03 feels the same as those with the pea sized amount of AW in it. 

 

[borderlord 8]

Hi Guys

Well the DT03 is ready for its test flight, and flight it may well be.

Here's the deal

500,000 cst came in this morning. Sticky or what !!!!!. Quite why they put it in a squeeze bottle with a spout I don't know, 'cause this stuff ain't squeezing anywhere.
I used a stick to pull some out, held it up and it just sat there, no flow, no drips, no nothing.
Reminds me of toffee, but more so.
Anyway, pulled the diff apart, cleaned the residue of the old stuff out and rebuilt it.
I know someone said they used heavier oil and the diff felt the same as before. Not so with this stuff.
Holding one wheel and turning the other felt very stiff. I hope this will ease up with use, but if heavier oil makes the diff act like a lsd, this one seems to have very little slip at all.
First corner will tell me. If I steer round it but the car goes straight on, then guess I have a problem, hence the possibility of a first 'flight'.
Rest of the build went together relatively easily, but one area I had a concern about.
First of all, I mounted the outer ball in the middle hole, as in the pictures. Might have been better in the inboard hole.
The instructions for the turnbuckles said 13mm between the inner ends of the links.
Started from there but that gave me about 8 degrees of negative camber. Wound the turnbuckles out till I had about a degree or so, but the gap between the link inner ends was now 19mm.
That means the threads penetrate less into the links than designed. Not sure whether this makes a weak point or not.
Did think about moving the balls to the inner hole, but since they are cyano'ed in that would have been a faff. Also wondered whether to use the longer turnbuckles.
The rear ones are 32mm long, but since I will be keeping the front plastic wishbones that leaves the front turnbuckles, which are 38mm long, at a loose end.
They would give me more thread inside the links.
Finally decided to leave it as it is, just keep and eye open for any signs of stress in that area.
So, just need some dry weather and we'll see what happens.

Wish me luck

Jeff

[ThunderDragonCy 7885]

Don't worry about the diff. Properly set ball diffs feel super stiff. I would pop the 38mm turnbuckle in if it's going spare. You want an out 3 deg neg camber at the rear to start with I reckon.

[borderlord 8]

Hi Cy

Thanks for that, but it's a gear diff. Does that make any difference?

Jeff

[ThunderDragonCy 7885]

13 hours ago, borderlord said:

Hi Cy

Thanks for that, but it's a gear diff. Does that make any difference?

Jeff

My point was that on the rear diff with thick "oil" in it you were concerned how stiff it is. I was trying to reassure you that ball diffs also feel really stiff when setup properly, so don't worry about it on yours. Just drive and see how you go. 👍