Dirt Thrasher rebuild

[Aerobert]

Today I finished the rebuild of my Dirt Thrasher. It took a little more effort than expected but I'm really happy with the result.

I've found this car as a part of a lot of Tamiya cars on a popular german classifieds website. I've asked the seller if he is willing to split the lot and sell the Dirt Thrasher separately and after a short negotiation we agreed a price which was actually my first thought how much I am willing to pay. The Dirt Thrasher was offered as unused which turned out not to be the absolute truth. After a week of waiting the parcel arrived:

Inside the box I found a complete build chassis with broken front uprights on both sides which let me know that the car can't be unused and makes me wonder what happend (new uprights were also in the box). Also a not so good cut body and wing without protective film and some scratches was inside the box. Some bits were missing, like one wheel nut and a shaft for the wheels or the lexan hatch for the body which was later replaced with a selfmade styrene part. As I wanted to rebuild the chassis anyway I had ordered some bits for it directly after I bought the car. After a short research here in the forum about the vintage DF-01 chassis I ordered the Tamiya 50529 Plastic Gear Set, a steel pinion, ball bearings and because one where missing four red wheel nuts.

During rebuild the chassis if noticed some minor mistakes and a major one which on first sight doesn't seem to be so bad as the consequences: The ball connectors D3 for the steering and the ends D4 for the dampers were interchanged. This makes the steering that tight that it must be impossible to control the car which leads to the broken front uprights. I guess after that the car went back into the box and stayed there up to now. Probably an inexperienced or impatient modeler has build the car, which would explain why none of the gates from the moulding were decently removed.

The rebuild was completed quickly with a brushless set and a new servo:

After that the body needs some attention. It was badly cut from the initial builder which leads to a bit more cutting than intended by Tamiya.

But also this issue was solved and after that the whole body needs to be masked.

Painting of the body was an easy job, as I though, until I've realized that I've missed the the note for PS-4 (blue) in the manual and painted the complete body white. And to make it even worst I used to old smoke grey for tinting the windows which leads to speckled paint:

At least I could rescue the windows which are clear now. And although the missing blue paint is not box art but I like it anyway.

The result is pretty good I think (although I'm not an decal artist).

As a summary of my first rebuild of a car which was not build initially by myself I could say that it was great fun, also if I sometimes was a little bit confused about the quality of the initial build. And building without taking the parts from the tree is a little bit more challenging with an unknown chassis / model.

I'm really happy with it and will now patiently wait for better weather for it's first run after rebuild. Let me know what you think about it.

Cheers,

Robert

[Baddon]

pity I cant see the photos as I just bought a Manta ray bashed to convert to a Dirt Thrasher. 

[Aerobert]

15 minutes ago, Baddon said:

pity I cant see the photos as I just bought a Manta ray bashed to convert to a Dirt Thrasher. 

I will try to fix it. From my side everything seem to be okay.

[Aerobert]

Should be working now.

[Problemchild]

I’m not seeing any pics 

JJ

[ACCEL]

8 hours ago, Baddon said:

pity I cant see the photos as I just bought a Manta ray bashed to convert to a Dirt Thrasher. 

I can't see!

[Baddon]

still not available

 

[Aerobert]

Next try.  Unfortunately I am not an computer expert. I've insert new links for the pictures and in an other browser where I'm not logged into the forum and the photo host  I can see the pics now. If it is not working now for you I have to look for another photo host. Sorry for that.

[Problemchild]

Working

thata a lovely looking car - I want one 

 

JJ

[Aerobert]

I've done a very short spin in the backyard with the Dirt Thrasher today and without any obvious reason the steering linkage broke at the ball connector. Maybe it was partially fractured before. The broken part is included in the  C-part sprue which is available in black and blue plastic. Is there any particular difference in material properties between those parts beside the colour? Or should I directly swap to a aluminium steering?

Thanks.

[Problemchild]

Must have been damaged already or just brittle 

depends what you want to do 

potentially just get a replacement part and keep it all original 

is it not the red bit?

JJ

[Aerobert]

On 4/25/2020 at 8:01 PM, Problemchild said:

Must have been damaged already or just brittle 

depends what you want to do 

potentially just get a replacement part and keep it all original 

is it not the red bit?

JJ

Here is a picture. The question is if this is a weak point in the steering or just bad luck.

 

Edited August 30, 2021 by Aerobert
Compressed picture

[Hobgoblin]

I never had this fail. I only changed because of the slop.

I have 3 spare sets and could send you one if you're uk/Europe 

[Aerobert]

59 minutes ago, Hobgoblin said:

I never had this fail. I only changed because of the slop.

I have 3 spare sets and could send you one if you're uk/Europe 

Thank you. I'm located in Germany, therefore it would be possible. But a s I also have to order some spare parts for my other cars I will order the C-parts also as they are pretty cheap. But thank you again for your offer. 

[Problemchild]

Looks like the ball has been over-tightened until it’s stripped the plastic 

JJ

[Aerobert]

That's probably the reason. Don't know how it was build as I bought it second hand. The broken part will be replaced with the standard spare part.

[Aerobert]

Thermal problems!

Finally I've managed to replace the broken steering horn. After that I've took the Dirt Trasher for a little spin in the backyard. Wasn't a long run, maybe five minutes. Then the car was very slow. I thought it would be the LiPo cut-off as I wasn't sure about the charge state. But after removing the body shell I already noticed that the whole car was warm. The LiPo was hand warm, motor and ESC were very hot. 

What could be the reason for this? Is it the gearing of the car? I've installed a 21 T pinion. Motor is a 12 turns brushed from Losi also the ESC. The LiPo is 2S. Or is there too less cooling due to the close fitting body? Was a warm day (28° C) today.

Thank you.

 

[ThunderDragonCy]

13 hours ago, Aerobert said:

Thermal problems!

Finally I've managed to replace the broken steering horn. After that I've took the Dirt Trasher for a little spin in the backyard. Wasn't a long run, maybe five minutes. Then the car was very slow. I thought it would be the LiPo cut-off as I wasn't sure about the charge state. But after removing the body shell I already noticed that the whole car was warm. The LiPo was hand warm, motor and ESC were very hot. 

What could be the reason for this? Is it the gearing of the car? I've installed a 21 T pinion. Motor is a 12 turns brushed from Losi also the ESC. The LiPo is 2S. Or is there too less cooling due to the close fitting body? Was a warm day (28° C) today.

Thank you.

 

Definitely gearing. For a brushed mitor5 that low turn you need to go to the opposite end on gearing. Get a steel 16t 0.6mod pinion (doesn't have to be a tamiya item) and try again. 

[Aerobert]

32 minutes ago, ThunderDragonCy said:

Definitely gearing. For a brushed mitor5 that low turn you need to go to the opposite end on gearing. Get a steel 16t 0.6mod pinion (doesn't have to be a tamiya item) and try again. 

Thank you. I will order a 16 T pinion. Meanwhile I will change the motor. What do you think is the minimum of turns for a 21 T pinion?

[ThunderDragonCy]

4 hours ago, Aerobert said:

Thank you. I will order a 16 T pinion. Meanwhile I will change the motor. What do you think is the minimum of turns for a 21 T pinion?

Not sure. I am a bit clueless about brushed motor gearing 

[Aerobert]

7 hours ago, ThunderDragonCy said:

Not sure. I am a bit clueless about brushed motor gearing 

I am also. I've swaped the motor today and put in a Dirt Tuned 27 T. I've also re-programmed the ESC. Now it's running pretty good. Motor is still getting very warm but not so hot as the 12 T. Maybe I will put in a 20 or 19 t pinion. Thanks for your help.