CrankyCat

Hi,
recently I found a nitro RC car in the dumpster!!! I think it is an "HPI TROPHY TRUGGY 4.6". amazingly it was in real good condition and honestly no Idea why someone throws away something like that! anyways it has no remote control and the battery holder was corroded.... I liked to drive it and though it is the best to test the engine before getting more involved and make sure everything is in order before buying anything for the car.
So I hooked up the servos to an Arduino and tested the servos and they worked fine. later I got some 20% nitro and start the engine. (I used alligator clips and AA batteries). after some trial and error, it starts. because there isn't a remote control to control the throttle yet! (or I thought that's the reason anyway) the engine and wheels were running extremely fast, later I learned If I push the throttle/brake lever, it stops the wheels and slows the engine. but after 1-2 minutes, I realised the car start smoking from the clutch and the smell is different from the burning oils from exhausts. I think the needles was set to very high (as it emptied the tank in 4-5 minutes) and by braking, I just burned the clutch or brake or something! I even think the gears are decolored because of high temperature but not sure entirely as I check the clutch and brake assembly temperature with my infrared gun and it was around 130 ...
my question is, did I just ruined the clutch or brakes and how a newbie like me safely test and set up/tune the car as I don't like to send the car back to the dumpster
Al

cbaker65

Yes ,you fried the clutch ,an you should of never ran it with that high of an idle ,the idle set screw is probably set to high!
That's probably why it ended up in the dumpster ,the owner didn't know how to tune it!

CrankyCat

Thanks for the reply, is there any test to see if clutch and brake definitely toasted or it is just the performance comparison. beside disassembling and visually inspect them....
thanks

cbaker65

Actually ,each time you turn that receiver on ,the servo is going to keep opening up the carb,because you don't have the transmitter to the truck!
It takes a transmitter to send a signal to keep the servo in the neutral position!

You need to purchase a new radio gear set ,its simple an cheap to replace ,its only $ 40 or $ 50 bucks an the trophy truck is well worth it!..

CrankyCat

Cheers mate! The 1st thing I did after it started was jumping online and ordered the original transmitter and some other things like plugs and filters. But the thing is so cool you can't wait for the parcels to arrive. As I living in Australia, it takes ages for parcels to arrive ((

krokodyl

You can have a look at the clutch by undoing the 4 engine screws, and then take on e-clip off... You will have to replace it anyways.

A radio is obviously going to be needed. A 3 channel flysky for $30 on hobbbypartz will work. Once you get that, you can start trying to run it. If it won't run, set the needles back to factory settings, and start over.

Hubert

CrankyCat

Thanks, I'm not sure if I going to open the clutch yet as if I open the clutch probably there will be too many things to worry about after I reassemble the machine! but yes I already ordered an HPI radio to match the existing receivers it sent from US and I know its gonna be a very long week for me
I think after setting the radio I'm going to set the carb and engine and when they tuned probably going to check the clutch... at this moment I'm struggling to get the engine even starting... everything is out off whack and I don't have any clue how to fix the thing!

krokodyl

If the clutch is messed up, which it sounds like it is, then it probly won't start. As I mentioned, it's easily accesible, and it's pretty hard to mess something up. Download the manual, it should have instructions or at least a exploded view of the clutch removal.

Hubert

mattster1971

Clutch shoes are easy to replace. YouTube for a video of how to replace them. Then you need to dial back the idle, the shoes should not engage when Idling. There may be a broken clutch spring also which would account for them always being engaged.

CrankyCat

Hi everyone, thanks for replies! here is a quick update. ofter lots of tinkering, I opened the Carb and cleaned it up with ethanol and a little bit of acetone! (I read they use it in fuel mix sometimes for nitro subsite so shouldn't be too bad) there was a lots of dried gunks inside Carb. I guess the previous owner just store it without cleaning or they used wrong oils in the mix...
anyways its back to good conditions now! so I started the engine after clean up and resetting valves and to my surprise its start perfectly!!! it's Idling ok and everything seems working great! I pushed the throttle servo and the car jumped and ran away. (it stopped at the end hitting a very steep slope in backyard ) so I guess the clutch and carb should be fine!
now it just a waiting game as I haven't received my transmitter yet!
it arrived in Australia but stuck somewhere in customs or OSPost

CrankyCat

Hi,
just a quick update regarding the buggy.
I finally received the transmitter and set up the car. it was a lot of fun and FAST!
I uploaded videos on youtube:

https://youtu.be/jk98r-_Obis

https://youtu.be/oOhz6qZOX6M

the clutch and pads are fine. I hooked up my old iPhone to the car and the Max speed was 70 Km/H
the engine temperature was around 115 and goog trail of smoke.
the only thing that ruined my day was the pull starter cord which was burned and snapped ...
I ordered some blind cord from ebay and they sent me 5 cm length!!!!!
now I'm thinking about a new pull starter or maybe a drilled one
thank you all for the help and suggestions

DriveForFun

Congrats on the awesome score!! I'm really wanting to make the leap to Nitro but wife is getting fed up of RC cars showing up at the house.....better start dumpster diving!

CrankyCat