8041 Race Truck motorization

[tomacwhite]

Model: 8041 Race Truck

Modification:

- Steering from PF 'M' Motor

- Drive from PF 'M' Motor

- Lego Technic V8 engine kept intact

Firstly, I'd like to give credit to two users because I borrowed a couple of ideas. I used the controller steering wheel design that Jurgen Krooshoop designed for his fantastic red and yellow race cars. Thank you very much for the design, it works brilliantly. Secondly, I used the hockey spring idea that I saw mahjqa put on his website. The idea works perfectly and I managed to aquire the said Hockey Spring from Bricklink for £2.50.

OK, so for me my primary importance was to keep the V8 engine on the truck because I felt that it added a lot to the overall shape of the Race Truck, so to remove it would ruin the design. With this in mind, I had to think about a more clever way of mounting the motor. It might not be as efficient as other methods, but more on that (and gearing) later.

As you can see the 'M' Power Function motor is mounted vertically, the IR sensor sits on top of the engine, and the battery box slides down the back of the body of the cab (with a couple of beams and Technic plates to make a perfect fit). I also changed the exhaust piece, the tubing now goes into one of the holes on the IR unit, and I dropped the 'tank' down as it blocked the pistons from view and didn't sit very well otherwise.

As you can see the battery box fits perfectly in the back of the cab. I just added two parts per side, plus an axle for it to sit on. I then added a small 'L' beam with pin to lock it into place.

I needed to add an extension cable for the drive motor so I tucked it down the left side of the truck with a pin/plate piece which seems to work nicely.

Steering is achieved via a vertically placed 'M' Motor connected to the Hand of God steering axle, and you can see the white Hockey Spring piece which works perfectly.

The rear motor mount close up:

With this set up the Race Truck drives at an OK speed, but it can hardly be called quick. I am not sure how to gear it up really, could anyone advise? I also bought a 'XL' Motor but that is slower, so needs gearing up by quite a bit. Some advice on how to gear it up would be great! I am new to modding so advice on what gears to use etc would be very helpful! Do I need to have a larger gear on the motor, then a smaller one at the drive end? The problem there is that the differential is quite a big gear in itself.

Overall I am very happy with what I've done, the truck is ace now its drivable, it just needs to be made quicker!

[Jurgen Krooshoop]

Nice job, and thank you for crediting. You mean you used this remote controller ? I think it feels comfortable and logical.

[tomacwhite]

Yep, that's it. Its great, and feels really natural :)

[Jurgen Krooshoop]

And for a lot of good info about gears and gearing, you can check Sariel's Gear Tutorial. It'll propably answer all your questions about bigger and smaller gears.

[tomacwhite]

Oh brilliant, thanks! :)

I think I might run out of space to do too much with the Race Truck, but we'll see. I am going to try and build my own car soon, which I am sure will be very, very hard!

[Flare]

Sweet!

[tomacwhite]

Small update: I have just increasted speed significantly by gearing up (using the handy guide provided by Jurgen). I have put in my XL motor which has a 24 tooth gear attached to it, then linked to an 8 tooth gear which links to the 20 tooth double-bevel gear like before. Speed is much better now.

I need to tidy up the mounting of these gears and I will take a couple of shots and post them up later. I would like to try and get some more speed out of it, but it might be a challenge as I still have to get to the diff via 2x double-bevel 20 tooth gears.

[tomacwhite]

As you can see the structure isn't quite final now, but the truck is much, much faster to play with.

[Bricksonwheels]

That is a great truck, really like the cabin. The engine on the rear looks a bit out of place, but i guess there was no room anymore. Great work.

[eMHa]

Hi,

As you can see the structure isn't quite final now, but the truck is much, much faster to play with.

this seems to get yery high! Couldn't you use the 20 tooth gear from the diff which goes to the piston motor? You could then attach the motors horizontal. Or add a 12 tooth to the axle which goes to the piston motor and gear up from there?

Nevertheless, nice MOD.

[tomacwhite]

Hi,

this seems to get yery high! Couldn't you use the 20 tooth gear from the diff which goes to the piston motor? You could then attach the motors horizontal. Or add a 12 tooth to the axle which goes to the piston motor and gear up from there?

Nevertheless, nice MOD.

Hi, thanks for the feedback. Space is quite tight around that area of the model but like you said I might try to power the axle which is going from the diff to the V8 engine, that way allowing horizontal placement of the PF 'XL' motor.

Thanks :)