Howard's Manta Raycer

[Howards 894]

Let's do some 'vintage' racing.

Stotfold MC has their 40th anniversary of being on the same site, and I'm going to need some kind of 'vintage' chassis for the retro event on the day. I'm a bit of grouch about how much folks will spend on this kind of thing and how much their 'vintage' class chassis do not resemble the actual model any more once they have entered the race, so I'm setting out trying to stay relatively close to the design of the chassis and spend as little as possible whilst still being able to keep up.

I reckon the cheapest way in to this - and be competitive - is some variant of the DF01 chassis, so I picked up this 2018 Manta Ray for what felt like a great price. 

We know what the DF01 weak spots are, so picked up the front and rear reinforcement kit from Concorde on here, a fancy propeller shaft, alloy motor mount and two sets of slightly different UJs. This is intended to be a budget racing build so I don't want to spend a huge amount more on it, but I'll also get a ball diff for the rear, slipper pinion, some kind of replacement for the alloy idlers and maybe the xtraspeed oil diff conversion doobries for the gear diffs. 

[Howards 894]

Running gear choices:

1. 120blG2 speedo. These are great, and good value. 
2. Tamiya 10.5 motor. I have a couple of these kicking around so it seems like a fair place to start. If it's too slow with the slightly odd DF01 FDR I'll fit a 7.5 I've got kicking around.
3. Old but nippy Savox servo. Funny story about this one - I leant it to someone at a club when their servo died. They agreed to give it back the next time they were at the club. They didn't say that would be in six months time... so I assume this one has been on a bit of an adventure already. 
4. Radiolink receiver. Fantastic value for such a fully featured RX/TX.
    

[ThunderDragonCy 9082]

Nice! Looking forward to seeing how you do with this. Vintage buggy racing totally puts me off for all the reasons you mention. May I suggest the TA02 High Speed gearset? Deletes the alloy idler and gives you brushless suitable gearing options. Twofer.

[matisse 1728]

20 minutes ago, ThunderDragonCy said:

Nice! Looking forward to seeing how you do with this. Vintage buggy racing totally puts me off for all the reasons you mention. May I suggest the TA02 High Speed gearset? Deletes the alloy idler and gives you brushless suitable gearing options. Twofer.

I approve of this message.

Extended screws through the gearboxes is a solid plan too.

[Howards 894]

Yeah, I'll either get the gearset or the delrin idlers. Or both. The kit FDR looks ok for a 10.5, probably pretty good for 8.5 or 7.5 (I have both kicking around). Assume fitting 2.2" wheels brings the kit FDR a touch closer to what brushless set ups need.

[Saito2 8441]

3 hours ago, Howards said:

I'm a bit of grouch about how much folks will spend on this kind of thing and how much their 'vintage' class chassis do not resemble the actual model any more once they have entered the race, so I'm setting out trying to stay relatively close to the design of the chassis and spend as little as possible whilst still being able to keep up.

Then I am a fellow grouch myself. I applaud your efforts and look forward to seeing the results.

[Howards 894]

TA03 ball diff ordered. Found one at a fair price on eBay and neither Plaza nor RCjaz seem to have them. 

Does it come with the plastic idlers? I’m not 100% on what I need to buy to get all the dodgy gears out of the rear gearbox. 

[ThunderDragonCy 9082]

1 hour ago, Howards said:

Does it come with the plastic idlers? I’m not 100% on what I need to buy to get all the dodgy gears out of the rear gearbox. 

It comes with a plastic idler, but that metal counter gear on the spur gear shaft. Even if you don't change to the high speed gearset, you will need the TA02 Plastic Touring Car gearset to get rid of all the metal bits. If it were me I would still get the ta02 high speed gearset as you get two full plastic spur/counter gear options and they get rid of the dodgy alloy gear from the kit

[Howards 894]

5 hours ago, ThunderDragonCy said:

It comes with a plastic idler, but that metal counter gear on the spur gear shaft. Even if you don't change to the high speed gearset, you will need the TA02 Plastic Touring Car gearset to get rid of all the metal bits. If it were me I would still get the ta02 high speed gearset as you get two full plastic spur/counter gear options and they get rid of the dodgy alloy gear from the kit

Ta. I’ve ordered the TA02 high speed set. 

[Howards 894]

Let’s go to town on this 

[Howards 894]

Ball diff for the rear arrived. Research indicates I’m best off gluing the outdrives in to the plates to prevent the splines from wearing. Green Threadlock? Or something more industrial like JBWeld?

[Thommo 1475]

I think you want the hard cup joint for ball diff.  JB weld is a bit extreme 🤣

[ThunderDragonCy 9082]

Threadlock. You definitely need to stop them wandering out.

[StueyS 52]

If you are clamping the rear gear case down and changing the counter gear, I wouldn't worry about a slipper pinion. Many people run the kit rear diff with some very thick diff oil or grease as it's much more reliable than the spline outputs. The ball diff should be fine in the front. When I bought my TF it came with a RW racing coubter gear instead of the metal one, might still be available?

I saw the meeting mentioned, is it invitation only? Not raced there for about 20 years now.

[Howards 894]

13 hours ago, StueyS said:

I wouldn't worry about a slipper pinion

I’m luke warm on it, sure. But….high grip astro….

the spline thing…ah it’s a silly design choice. I assumed the best fix for that is just to bond the parts together in the strongest form possible. Remove all play, maximise contact area to spread the load etc. I’ll take a good look at the kit gear diff though, I did think it looked tough. 

as I understand it, the event has an invite only class and general entry but I think they are releasing more info soon. 

the track is still great but it’s all astro now. Even mill end is heading in that direction. One buggy meeting in feb and you learn. 

 

 

[StueyS 52]

The problem with fixing the splines in semi- permanently is when you need to change the bearings. Someone is running one very well at Herts and many TF run on high grip with little problems these days with the gearbox cover mods. Best not go land jumps on the power though to help. I am hoping to go to Mill End soon to run my Rally car and maybe some vintage.

[Pylon80 4281]

@Howards I know some Tamiya instructions with a similar diff were calling for using "synthetic rubber cement" which apparently is to be interpreted as RTV. I am not sure where I saw that, perhaps the Egress manual or some high end vintage buggy or other? However, for what it is worth I have run that diff on my M-05 for perhaps 5h of postal racing until I swapped it for an M-05 diff and I never had the cups RTV'ed. I run my cars in the abrasive dust we have everywhere here. I did not see any sort of wear at all. Racing off-road like you will probably be doing  could be another story especially if it is outdoors or wet. So I would personally play it safe with a drop of RTV/ShooGoo/silicon bathroom sealant, just to prevent the dust and grit from going in there and prevent relative motion between the cups and the pressure plates. Do use something removable. This is a harder to find/expensive diff these days. I still have mine and it is going at the rear of a TL-01LA!

[Howards 894]

8 minutes ago, Pylon80 said:

Racing off-road like you will probably be doing  could be another story

It's possible to strip the splines on high grip surfaces I think. As there's no give in the drive, if the speed of the wheels don't match the speed of the chassis, say when landing a jump, that mismatch is expressed as strain on the transmission and the weakest part can give up. The contact area of the splines is, er, optimistic, and they can float around reducing it further. 

@StueyS I know the chap at Herts. I think he's running custom gear diffs. When he first ran it, it blew up in every heat and the final! That was hard to watch. I've since seen him do much better though and he's ironed the bugs out it seems. There's another chap who does very well with a Manta which seemed to be more reliable. 

[Superluminal 4174]

The ExoRC diff plates and outdrives look like a good upgrade to the splined kit ones

[Howards 894]

Oh man, I have not had the time I expected to work on this. Maybe tonight I'll build the ball diff now the loctite retaining compound has arrived. 

For folks who have built this chassis before, can I use hex machine screws in place of the self tappers? I've got the thread former but wondering the plastic just won't take 'em. I've noted that the YR ti. screw kit is hex..but the threads are still self tapping. 

[StueyS 52]

I have used machine screws in a number of places. Rather than trying to tap them, I use a little dab of silicone grease or similar before carefully screwing them in.

[Howards 894]

Ta. This diff is quaint! I like the way the balls only go in one way and the one piece thrust race. It’s Super light but doesn’t fill me with confidence 😹 

opted for ceramic balls given there’s only eight of them. 

Put a touch of blue threadlock on the bolt and broke it in with 30 seconds or so in the drill chuck. Has a slight tight spot which I’m not super happy about. 

[Howards 894]

Here we go…

[Howards 894]

On 3/16/2025 at 6:07 PM, Howards said:

 

Let’s go to town on this 

 

Turns out it takes a lot of work to get to town 

[Howards 894]

You know when you said you didn't want to spend too much on this. Well...

Searching for screws, I ended up hunting down the YR titanium screw set. Turned out RC Mart had some, but I couldn't face the postage on just one item. So. 

- YR Titanium screw set 
- YR Titanium turnbuckles 
- XtraSpeed alloy C hubs
- XtraSpeed alloy knuckles 
- XtraSpeed alloy rear uprights 
- XtraSpeed alloy oil filled diff adapter and internals 
- XtraSpeed alloy front lower diff case 
- Tamiya FRP shock towers 

How is it possible to love and despise a hobby at the same time?