Juhunio's Bits-A-Builds

[ThunderDragonCy 7876]

@Juhunio Strongly approve of your diligent part number nerdery 😉

[Juhunio 6830]

4 hours ago, ThunderDragonCy said:

@Juhunio Strongly approve of your diligent part number nerdery 😉

Churs! It’s fun finding the connections 👍

[Juhunio 6830]

Another little shuffle forwards today, replacing the rear arms with the 51104 parts. They're narrower so needed some spacers to fill out the suspension shaft, but while the 53899 LR Suspension Set is apparently compatible with the TA04, it doesn't include instructions for the TA04, so a bit of measuring and experimentation was required

In the end, 1x3mm spacer at the front and 2.7mm (2x1mm + 1x0.7mm) at the rear produced a good fit with no lateral slop but free movement while seeming to keep the centre point of the upright in the same position so as to maintain the wheelbase.

I also switched the suspension block from 0.5^o to 1^o, as the new uprights (currently wending their way from Japan) are also 1^o and 2^o of toe feels right.

There was a fair amount of guesswork involved so I'll more than likely need to tweak the spacers once the shell is on to get the wheelbase right

Time to (im)patiently wait for the uprights to turn up 

 

[svenb 3774]

Excellent as usual

I do prefer the carbon finish over the SSG but it definitely looks smart👍

[Juhunio 6830]

10 hours ago, svenb said:

I do prefer the carbon finish over the SSG but it definitely looks smart👍

I hear ya. My thinking was that while you can add CF to virtually any chassis, the SSG parts are a bit of a wildcard on the TA04 so I've gone that way to give it a point of difference. It's a TA04 'thing' right? 

[svenb 3774]

It's definitely a"thing" mate 👍

I'd say that a fully SSG'd 04 can't be that far from a trf414 handling wise!

Strangest use of SSG I've seen is the chassis brace for the TB02🤔

[Juhunio 6830]

1 hour ago, svenb said:

Strangest use of SSG I've seen is the chassis brace for the TB02🤔

Yup, it's a weird one alright *scratches head*

[svenb 3774]

29 minutes ago, Juhunio said:

Yup, it's a weird one alright *scratches head*

And because it has the shaped recess for it it HAS to be fitted🙄

[Juhunio 6830]

3 hours ago, svenb said:

And because it has the shaped recess for it it HAS to be fitted🙄

I know right? Who the heck is gonna just leave that gap there??!! 

[Tizer 606]

18 hours ago, Juhunio said:

Who the heck is gonna just leave that gap there??!! 

Hello!

[svenb 3774]

1 hour ago, Tizer said:

Hello!

 

our thoughts are with you!

[Juhunio 6830]

The rear uprights arrived! The build is back ON 

[Juhunio 6830]

I had a crack at putting the rear end together last night, and nearly made it....

New uprights, suspension shafts and turnbuckles for the upper arms

I used the TB-02R measurements from the 53899 set for the upper arms, which seemed ok, but needed to move the upper arm mount out two spaces on the damper mount. But I guess that's why they come with so many holes!

Then I moved onto the universals, using the new 42mm swing shafts

And while the shafts were fine, the axles I had....weren't

I was still using 'standard' universal axles (53499), forgetting that the 53899 Reversible Suspension set comes supplied with four axles...hmmmm, maybe they're specific to the reversible suspension? So I made a quick check on the TB-02R, Evo IV and Evo V manuals and yup, they all come with a different axle; 51094

Obvious really (good old hindsight); the uprights are narrower than standard so need a shorter axle to work. Otherwise you end up with this:

It also made me realise that to convert the front to the same suspension arms, the TA04 Uprights and Racing Hub Carriers aren't going to fit. I've got a set of Evo IV 2^o hub carriers left over from the TB-02R build, so they'll do, but I do now have another shopping list:

• 51094 axles x4
• 51103 front uprights
• 950 bearings x4

[Tizer 606]

I've fallen into the same trap a couple times as well. Tamiya really mixed&matched different versions of their touringcars together

[svenb 3774]

[Juhunio 6830]

Made a start on the front end today, with as many parts as I have managed to assemble. Sticking with the reversible suspension means different hub carriers, and I had these 2^o parts left over from the TB-02R build

But I quickly hit another bump in the road, which begs a question....has anyone out there ever actually got the 53899 Reversible Suspension Set to fit a TA-04? 

It's supposed to be compatible, and I got the rear to work, but I cannot see how the front can fit, particularly on a tub chassis

Firstly; there's a nib on the side of the gearbox which means you can only move the arms so far back. In itself this isn't a problem as with spacers the reversible arm centre sits in the same spot as the standards arms, so the wheelbase is consistent:

But secondly, there's also a raised rib on the tub, and because of the nib on the gearbox you can't get the arms far enough back to clear that rib, so the arm sits on top of the rib and the gearbox won't screw down

There just isn't enough width the in the arm to cover the rib on the chassis and the nib on the gearbox. So there's no way the reversible suspension arms fit a TA04

Unless they're only compatible with the CF / SSG chassis plates? Is that the thing?

I can't find an SSG lower deck at an acceptable price, and kind of wanted to keep it as a tub chassis anyway, so it's looking like reversible suspension on the rear and standard on the front 

[Juhunio 6830]

And a third point (I've had a bit of frustrating day!!)...

What's up with the angle on the front suspension pins from back to front?? Are they supposed to be so far off straight between the mounts? I've taken it apart and put it back together again about 6 times, and re-assembled it using the kit plastic mounts, and it's the same. Have I got a whack gearbox moulding, am I missing something obvious, or is this just the way it's meant to be?

[svenb 3774]

Only solution is to trim the nibs on the tub!

I've used a carbon chassis so can't help that much, have no clearance issues.

The front arms do kick up at the front,I suppose it gives a bit move caster.

[ThunderDragonCy 7876]

@Juhunio I expect the kick up is intentional. TA01-03 and FF01 all have front kick up and no Caster on the stock uprights. The arms only went flat from TA05. It adds Caster without needing angled uprights, and kickup does increase weight transfer and rides bumps better. Not something to worry about. Doesn't stop my TA02 or FF01 handling great. 

[Juhunio 6830]

9 hours ago, svenb said:

Only solution is to trim the nibs on the tub!

Dremel time!

[Juhunio 6830]

This is my chassis tub, a carbon reinforced part that I happily picked up for £17, so I didn't feel too guilty about cutting bits off it this morning!

A combination of the Dremel and hand files got rid of the back of the ribs, so the reversible suspension will now fit

A bit more improvisation there...the stabiliser arms are supposed to mount onto a small ball nut that screws into the front of the lower arms outboard of the damper mount ball connector. But there isn't a screw hole for the necessary connector on these reversible arms, so I found some 4mm adjusters left over from the 30th Anniversary 934 build and attached them on the small ball connector moulded into the inside of the arms instead. It might mean I need to trim the stabiliser rods a bit, but we'll cross that bridge when we get there...

 

[Juhunio 6830]

One last look at the front aluminium diff pulley before I attach the belt and put the lid on 

 

That's it for another couple of days, until the new axles and front uprights show up 

[Juhunio 6830]

Axles and uprights arrived courtesy of @svenb and Tony Tamiya so, as my father-in-law would say, we're sucking diesel again!

And yes, the axles are much shorter 

 

[Juhunio 6830]

The new axles and front uprights worked a treat. Along with the leftover hub carriers, that's lightweight reversible suspension fitted front and rear

[Juhunio 6830]

The next couple of steps cover installing the steering posts and building up the spur gear and pulleys, so lots of lovely parts involved

It also means a decision on spur / pinion choices. This is going to be my motor, an old-school Super Stock:

 

Aaaaaaaand....I'm confused 

The leaflet states a gear ratio of 7-8:1. I like to aim in the middle of these ranges, so let's call it 7.5

Based on the TA04 manual, that's a spur / pinion combo of 128/36 (making the FDR factor 2.135)

But on the back of the box it includes a recommended combo for the TA04 of 112/45.

This would create an FDR of 5.3, which isn't anywhere near the ratio specified in the leaflet...

Does anyone have any experience of these older motors and could offer any advice? Should I go by the leaflet or the box?

Let's face it, the likelihood of it being run is pretty slim, but I'd prefer to set it up 'right'