XV-01 Very Slow Build

[skom25 2179]

I decided to buy Savox below:

https://www.savoxusa.com/products/savsv0220mgp-high-voltage-standard-digital#description

It should fit and probably will not put too much pressure on electronics.

There is only one thing which can be bit problematic:

Distance between mount holes in servo is 50 mm. Distance between mount holes in chassis is 48 mm. Recommended Savox 1251 has 49.5 mm, so it has to fit somehow.

Ekhm, how to install it in chassis?

@BuggyGuy I found that you used it. Any tips?

[BuggyDad 5904]

14 minutes ago, skom25 said:

I decided to buy Savox below:

https://www.savoxusa.com/products/savsv0220mgp-high-voltage-standard-digital#description

It should fit and probably will not put too much pressure on electronics.

There is only one thing which can be bit problematic:

Distance between mount holes in servo is 50 mm. Distance between mount holes in chassis is 48 mm. Recommended Savox 1251 has 49.5 mm, so it has to fit somehow.

Ekhm, how to install it in chassis?

@BuggyDad I found that you used it. Any tips?

I haven't got a Savox in mine. I think mine has a SPT4412S in it. That's low profile so fit is no problem, as per manual I think.

However, when I rebuild my car I think I will fit the servo upright, as @Big Jon did here:

Small stones jamming the steering is a common enough event to modify for, although not on tarmac obviously. I will probably 3d print mounts to fit my servo height exactly. 

 

[skom25 2179]

2 minutes ago, BuggyDad said:

I haven't got a Savox in mine. I think mine has a SPT4412S in it. That's low profile so fit is no problem, as per manual I think.

However, when I rebuild my car I think I will fit the servo upright, as @Big Jon did here:

Small stones jamming the steering is a common enough event to modify for, although not on tarmac obviously. I will probably 3d print mounts to fit my servo height exactly. 

 

Really sorry, owner of that Savox is @BuggyGuy. LOL.

[Andreas W 2510]

I am doing the mod that Big Jon is describing as well.  I am waiting for a package from Asiatees with the servo mounts (and some other small stuff). On monday I fell for the temptation to run on the partially frozen gravel next to where I am running the current postal racing track. The revard: A small and invisible stone found it's way into the steering and was impossible to see in the dark. Lyckily I still had enough steering throw to the right,  so I was able to run the track and use up the pack. Exactly the same happened earlier this summer (on fine, sandy and compact gravel. Then I lost steering to the right completely. 

[skom25 2179]

Quick shopping today, because I needed servo horn. Servo should arrive tomorrow.

I bought whole High Torque Servo Saver set for TT-02. Why? Horn for XV-01 costs 61 PLN. TT-02 set costs... 71 PLN and contains almost the same horn. Almost, because it is little longer and has two holes. Lower hole is exactly on the same place as in XV-01 horn.

I can say only one thing: well done Tamiya. I believe that there are hundred reasons for price of that horn.

Next thing is diff repair kit. It costs around 2-3 Euros, so just bought it.

5000 oil because I am sure that 900 from kit is too thin. I do not know if I will use it in both diffs or just on front.

[skom25 2179]

In saw many very detailed builds on this Forum. I am not best at this but this time I want to show something more. Maybe it will be useful for someone.

I try to keep things tidy when I build new model. It is not possible during rebuilds but it is different story.

I ALWAYS prepare all parts first and then proceed with build.

I do not want to write about clean desk, so few words about tapping. To tap threads, I use Tamiya Thread Forming Tap.

When hole is open on opposite side, everything is simple. Just rotate till you see tip of tool.

When hole is not open, there are two options:

1. Make thread till you feel resistance

2. If hole is deep, usually whole thread on tool is more than enough

Method from pt 1 is totally fine. However, it can be problematic if plastic is bit soft and you are not able to feel that resistance. It was the same with small servo mount. I was not able to hold part and was not sure where is the end.

What in that case?

I put small o-ring on 2.5 hex key. You can put this into hole and use o-ring as mark.

I have the same o-ring on Tap. Just put the side by side and set o-ring on Tap, to match to that from hex key. I always leave about 0.5 mm less on Tap, to not go to the end of hole.

As you can see, I used hex stainless screws. You can easily buy them in many sizes, quite often with 2 mm incrementation. You can use Tamiya manual as guide but it is worth to measure part, because sometimes it is possible to use longer. Remember to put screw into hole and measure only thread!

Build update:

I installed servo! Savox 0220MG+

I used High Torque Servo Saver with TT-02 horn and aluminium Cap. To attach servo mount, I used screws with blue conical washers.

Probably after this sentence, I will be banned from forum.

At some point, I thought that there is too much blue. I was not able to do much, so only removed coat from edge of Cap. Now it is silver and matches screws. Just a tiny detail.

I also removed Savox badge and put black "carbon" sticker on the top of servo. I want this achieve "stealth" look. On photo above and below, that sticker looks quite bright. In reality difference is not so huge.

Installed in chassis:

I was afraid, that distance between mount holes would be too wide. I managed to attach mounts, that distance was just about 0.5 mm wider than holes in chassis. No issues during installation.

I ignored manual and have not used foam tape in front of servo. Instead of this, I used aluminium tape on both sides of chassis. I like this tape, it makes everything look very Pro  

I cannot say too much about servo itself. It is 0,01s slower than SRT servos in my buggies but in reality, I have feeling that it is bit faster. Hard to say anything.

[skom25 2179]

Good news: NN4 replacements are on the way!

Bad news: Caster Blocks are still not available. I hope that they will be available this week. That is the last information from LHS.

I prepared gearbox parts and threaded holes. Both parts which connect gearbox with chassis are from CRP sprue.

Instead of NN18 spacer below ball nut, I used aluminium version. On rear I used 1 mm spacer to have the same geometry as in stock kit.

Hint: i think it is better to use M3x14 or even M3x16 grub screw on front. I used M3x12 as in manual but because of 2 mm spacer, ball nut is threaded only to about half of height on grub screw. I decided that in worst scenario is better to shear ball nut than damage thread in plastic part.

[skom25 2179]

Some spares and Hop Ups arrived.

- Spare Belt

- Spare Spur 68T ( the same as for TT-02B which I already have)

- 3x6 Aluminium Screws

- VG Shocks Grease

- 18T Pulleys

Why I bought belt and spur, probably I do not have to explain.

Aluminium bolts I will use only in places which are not under load, like e.g. covers.

VG Grease because I just want to try it. I have three pairs of shocks to build/ rebuild.

Pulleys. I found that Pulleys from kit have quite sharp edges. I decided to buy "upgraded" version. Two sets cost almost four times less than one set of aluminium.

Finally NN4 spacers arrived. I bought them from company/ brand goBilda. They are aluminium. Maybe quality is not perfect but dimensions are correct and were quite cheap.

Because I have mentioned spacers, I can start with gearbox build. As previously, probably it will take some time. Additionally, I have some plans related to TT-02B.

Any Tips how to remove play from Idle Gear Shaft with NN4 spacer? My first idea is to build stock, put into gearbox and check play ( without screwing together). Then add spacer and do it again. Is this good plan or I missed something?

Probably I will leave some play, because my experience shows that when everything is screwed together, play is reduced significantly.

[skom25 2179]

Small but still some progress. I added battery cover nuts and blue bolts. To be honest mainly to see how they look.

Caster Blocks arrived!

If you are normal user, you buy one.

If you are bit afraid that something can go wrong, you buy two.

If you are just stu... me, you buy three.

I bought also spare Gears, Uprights and NN parts, mainly for spacers and servo mounts.

It means, that I have everything what I need.

I am still bit confused about diff oil. I know that it is the best, to just try and change if necessary. However, XV-01 is so complicated that I really do not want to do this after two runs

Shocks. I will be totally honest: once I tried aluminium version, CVAs are bit... not great.

I am also not sure which motor I want to use. Super Stocks are probably bit too much. Maintenance, hot etc. is not something I want again. Sport Tuned is stronger than Torque Tuned but has less Torque on low RPM. Torque Tuned is more like real rally car motor, but it is also bit weak on high RPM.

[bavee 1142]

On 11/24/2023 at 6:57 AM, skom25 said:

Any Tips how to remove play from Idle Gear Shaft with NN4 spacer? My first idea is to build stock, put into gearbox and check play ( without screwing together). Then add spacer and do it again. Is this good plan or I missed something?

Probably I will leave some play, because my experience shows that when everything is screwed together, play is reduced significantly.

This is what I did. And then trial and error.

[Big Jon 686]

On 11/23/2023 at 11:57 PM, skom25 said:

Some spares and Hop Ups arrived.

- Spare Belt

- Spare Spur 68T ( the same as for TT-02B which I already have)

- 3x6 Aluminium Screws

- VG Shocks Grease

- 18T Pulleys

Why I bought belt and spur, probably I do not have to explain.

Aluminium bolts I will use only in places which are not under load, like e.g. covers.

VG Grease because I just want to try it. I have three pairs of shocks to build/ rebuild.

Pulleys. I found that Pulleys from kit have quite sharp edges. I decided to buy "upgraded" version. Two sets cost almost four times less than one set of aluminium.

Finally NN4 spacers arrived. I bought them from company/ brand goBilda. They are aluminium. Maybe quality is not perfect but dimensions are correct and were quite cheap.

Because I have mentioned spacers, I can start with gearbox build. As previously, probably it will take some time. Additionally, I have some plans related to TT-02B.

Any Tips how to remove play from Idle Gear Shaft with NN4 spacer? My first idea is to build stock, put into gearbox and check play ( without screwing together). Then add spacer and do it again. Is this good plan or I missed something?

Probably I will leave some play, because my experience shows that when everything is screwed together, play is reduced significantly.

When I build gearboxes, I shim each gear individually if possible, screwing together the housing to check play, The XV is nice, because each shaft sticks out of the housing , making it much easier to check the assembly.

If you come across the carbon reinforced knuckle, snap em up. The last time I saw a set in stock, Ultimate RC was still a big thing. I bought a set in ‘15 or so. I’m currently using modified TRF 501 12 degree aluminum knuckles.

[skom25 2179]

Today I built uprights. This time everything went much better, but...

Once again, right upright is perfectly smooth, totally loose. Left has just a bit of friction. It is not binding, resistance or anything to worry about. It is just tighter than opposite side, and you can feel it only when you push really slow upright using one finger. Probably most of people would not even notice that, but I always like to have everything done perfectly. I had thought to maybe try again, but experience shows that "Better is the worst enemy of good". 

As previously, I used Hard Hex Ball Connectors and 1 mm blue spacer, to keep stock geometry.

I used kit screw for limiter. When I compared 3x10 from Tamiya and my 3x10 stainless hex, I found that Tamiya is shorter for about 0.5 mm. It does not matter during whole build, but it is angle limiter, so I wanted to stay with stock part.

[skom25 2179]

Front gears assembled.

I added shims, to remove some play on axle and hold pin on place. NN4 parts are replaced with aluminium spacers.

If you want to reduce play, remember what is goal: to hold pin in gear, not remove all movement. I believe it is designed that way for some reason. In total, I added 0.5 mm of shims.

On second axle, I added two 0.1 mm shims to separate plastic from bearings. Again, I do not see reason to remove all play.

Be aware of part pointed by knife. It is not mentioned in manual ( or only partialy), but one some has some kind of flange. This side should be on the bearing side.

I also sanded both plastic parts, just few moves to have flat surface.

To have information during e.g. rebuild,  I added information about shims to manual. You can use it as a guide, but it is worth to try different shims and just check play.

4 mm and 5 mm shims are needed. If you want shim only axle with pin, 4 mm shims are enough.

[skom25 2179]

I had some time today and built both gearboxes.

Parts which are not stock:

- Pulleys

- Carbon Reinforced motor mounts

I decided to buy aluminium pulleys, because once again, I sold some bike parts and had extra money. Rule is simple: money from hobby, can be spent on hobby.

Carbon Reinforced parts are really hard. Even with tap, it was not simple to make threads.

As in manual, I used threadlock on motor plate. I have not used it on bolts, but put small dot on threads of motor plate.

Next step is to attach carbon shock towers. I have still not decided to glue or not glue edges. Probably not, because I do not see reason to do this. Towers are covered by body, so chance that they will be damaged is almost zero.

I also have to build diffs. Probably I will use 5k oil in both, but... I started to play Dirt Rally 2.0 on my Xbox X. I realised, that it can be good way to find how car handles with different diffs settings. It seems, that around 50/50 is best for high grip surfaces. Maybe 40/60 F/R even bit better.

Of course, it is game and I want to compare it to RC car, but since XV-01 is described as quite realistic because of motor placement, it can work...

[skom25 2179]

Completely by accident, I found that my LHS has Aluminium Diff Covers in stock!

I have not thought too much and just bought them. I heard about leaky diffs, so why not to get rid of problem at start? 

As far as I know, main problem is that plastic diff cover bends. I had the same issue with TT-02B. Aluminium covers should fix that.

Other:

M3x8 Aluminium Screws

M3x8/10 Steel Screws

Why I bought steel screws, I will show later. Aluminium are just for fun. I have few places where it is fine to use them, without any risk.

[skom25 2179]

Yesterday I prepared Diffs. It was my first time with Oil Diffs, so was not sure about effect.

As always, I prepared everything first, to just focus on assembly. Except of stock Diffs, I used:

- TRF Blue O-rings

- Aluminium Diff Covers

- TRF O-rings Grease

- 5k Oil

Assembly was quite easy. No surprises. 5k oil is thicker than I expected, but seems to be good choice. Not stiff at all, but also not loose.

I used grease on O-rings and just a bit on gaskets. Before I put gears inside, I put some oil on all parts, just to be sure that everything will be covered. I did the same on cross, before gears installation.

Issues?

Yes.

Somehow, gasket on one diff was not perfectly centered. Probably it was also bent, because my mistake. Material is quite stiff, so when it bent, probably gasket was not good anymore. After about 1h after assembly, I found that diff is leaking. Oil was visible on edge of case/ gasket/ cover.

Because I have spare gaskets, I replaced it quickly to leave diffs overnight and check today. Now everything is fine. Yesterday I cleaned both diffs with alcohol, to see even small leaks. No signs of oil after about 10h. Today I will rotate them from time to time and check for leaks. If everything will be fine, I will install them today in chassis.

It seems that I do not like to build oil diffs. There are few things that can go wrong. At that point, oil diffs together with shocks, are on the list: things I do not like to do in RC  

Answer why I bought steel hex screws:

I just could not stand standard screws. I was surprised, how cheap they were. Less than 2 Euros for ten.

Carbon shock towers fit perfectly, however I am surprised that there is almost no gap between tower and engine/ spur cover. It is like 0,1 mm or even less.

[Pylon80 3693]

8 hours ago, skom25 said:

Yesterday I prepared Diffs. It was my first time with Oil Diffs, so was not sure about effect.

As always, I prepared everything first, to just focus on assembly. Except of stock Diffs, I used:

- TRF Blue O-rings

- Aluminium Diff Covers

- TRF O-rings Grease

- 5k Oil

Assembly was quite easy. No surprises. 5k oil is thicker than I expected, but seems to be good choice. Not stiff at all, but also not loose.

I used grease on O-rings and just a bit on gaskets. Before I put gears inside, I put some oil on all parts, just to be sure that everything will be covered. I did the same on cross, before gears installation.

Issues?

Yes.

Somehow, gasket on one diff was not perfectly centered. Probably it was also bent, because my mistake. Material is quite stiff, so when it bent, probably gasket was not good anymore. After about 1h after assembly, I found that diff is leaking. Oil was visible on edge of case/ gasket/ cover.

Because I have spare gaskets, I replaced it quickly to leave diffs overnight and check today. Now everything is fine. Yesterday I cleaned both diffs with alcohol, to see even small leaks. No signs of oil after about 10h. Today I will rotate them from time to time and check for leaks. If everything will be fine, I will install them today in chassis.

It seems that I do not like to build oil diffs. There are few things that can go wrong. At that point, oil diffs together with shocks, are on the list: things I do not like to do in RC  

Answer why I bought steel hex screws:

I just could not stand standard screws. I was surprised, how cheap they were. Less than 2 Euros for ten.

Carbon shock towers fit perfectly, however I am surprised that there is almost no gap between tower and engine/ spur cover. It is like 0,1 mm or even less.

You can sand the diff case face gently on 1000 grit sandpaper, wet, to give it a perfectly smooth surface. Sand in a piece of glass. You do that AFTER having done a dry fit of the covers and screws, since the screws tend to raise the edges around the holes, which then make things leak.

Then you smear the gaskets with the goopy grease (which I think you did already). And finally the trick is to tighten the screws just enough that you do not deform the covers. Think of someone wearing a button down shirt that's too small and how the fabric spreads open between the buttons. The same thing happen when you over tighten a diff cover. Even the aluminum ones are flexible as screws can generate a tremendous amount of tension. I try to tighten them to the absolute minimum such that it won't leak.

Generally speaking, it's a pain. I much prefer ball diffs when it's available

 

[skom25 2179]

4 minutes ago, Pylon80 said:

Generally speaking, it's a pain. I much prefer ball diffs when it's available

That was my first thought today  

After next few hours diffs looked fine, so I decided to install them.

I started with grease on gears. Not too much. Just to see that gears are wet. I applied it with brush.

The same procedure on diff. This time I used it a little more. Just to see some white, greasy spots. Then I removed excess from edges.

I am surprised, how perfectly smooth is whole drivetrain. I expected that I will be nice, because of gears position, but have not expected so perfect smoothness. 

Now I am on that strange stage, that car seems to be almost completed, but at the same time I know that there are still hundred small parts waiting.

Next step?

Check all screws once again and attach all main parts to chassis.

[skom25 2179]

Finally I have some time to spend on RC.

I attached both gearboxes. Once again, nothing special except one thing:

I have not had M3x18 screws to attach bracket to gearbox, so I used M3x20 with 2mm spacers. I did the same on both ends, to keep symmetry ( and of course more blue parts!).

One suggestion to build. Do not attach bracket to gearbox and then to chassis. Just leave it loose, screw gearbox to chassis, then bracket to chassis and at the end both screws which connect gearbox with chassis. If you follow my steps, you can be sure there will not be unnecessary tension on parts and everything will go smooth.

Photo below shows that place and mentioned spacers. 

Final effect:

Now it is time for turnbuckles 

[NM Frontier 13]

Very nice build so far! I’m looking forward to seeing your shock build, I am very intrigued by using the TRF shafts and pistons in the cva bodys. Those blue diff covers are gorgeous! Gear diffs can be messy to build but I much prefer the tuning with the diff oil vs adjusting ball diffs especially for off road use. Keep up the great work!

[skom25 2179]

8 minutes ago, NM Frontier said:

Very nice build so far! I’m looking forward to seeing your shock build, I am very intrigued by using the TRF shafts and pistons in the cva bodys. Those blue diff covers are gorgeous! Gear diffs can be messy to build but I much prefer the tuning with the diff oil vs adjusting ball diffs especially for off road use. Keep up the great work!

Thank you!

I can already tell you, that TRF pistons will be totally fine. I used that setup in DT-03.

I am not sure about shafts. Someone mentioned, probably @Pylon80, that they are bit tight with red o-rings. Solution is to use blue o-rings, but this time, I read that they are not recommended to use with CVAs

Of course, oil diffs are great if we are talking about adjustability. They are just annoying to build, like everything what have to be sealed.

[Pylon80 3693]

44 minutes ago, skom25 said:

Thank you!

I can already tell you, that TRF pistons will be totally fine. I used that setup in DT-03.

I am not sure about shafts. Someone mentioned, probably @Pylon80, that they are bit tight with red o-rings. Solution is to use blue o-rings, but this time, I read that they are not recommended to use with CVAs

Of course, oil diffs are great if we are talking about adjustability. They are just annoying to build, like everything what have to be sealed.

I do have a set of CVA with TRF shafts and I needed the blue o-rings to make them work.

[skom25 2179]

@Pylon80

So do you confirm, that blue o-rings can be used with CVAs? Can I ask you for catalogue # of o-rings?

[Pylon80 3693]

That would be 42359.

[NM Frontier 13]

Awesome info!