Some questions.

[bigben]

Evening everyone, I am not sure if I should have attached this to the previous thread or not, but I will start a new one anyway. Well, I got my car and finaly got around to running it today. (Well sort of) It took me forever to get it running (ended up paying a kid at a hobby shop 20 to tell me I had flooded the engine) Nerveless I finally got it running for 1 take of gas. (Although I swear I ran an entire tank of fuel through it by hand cranking the engine) I ran into a few things and I am hoping I can ask all of you for your suggestions.

1) When running the car moved around great at first. Then it just stopped moving forward. The engine was running fine, the gears along side the engine (Sorry for not knowing the technical terms) were spinning when I gave the engine some gas. The half shafts err dog bones were spinning but the tires would not. The rims did not appear to be spinning (thinking the glue broke loose). When I lifted the back end of the engine off the ground the tires would begin to spin. Could you possible recommend any resolutions?

2) The front tires seem to point to one side. When I turn on the receiver and transmitter, the front tires angle towards the right slightly. Can this be fixed by shortening or lengthening the connecting rod from the server to the steering arm?

3) To rich or too lean. I have been given 4 different ways of breaking the engine it by for different people. I think I will stick to the 5 fuel tanks turning the fuel back a little at a time. I followed those directions and tested the cylinder head by dropping a drop of water on the head to see if it will evaporate and it was not evaporating. However, I am wondering about the color of the exhaust smoke. When idling the there is no smoke at all. However as I added a tiny bit of fuel it began to smoke blue slightly. Is there supposed to be any smoke? If so, what color and when? Any input you can give me on this I would very appreciative to know.


4) Best way to hold the body down when starting? I seem to have to push it all the way to the ground to be able to pull start the engine. Is it o.k. to bottom out the body and hold it down to start it?

Well, I am sorry to ask all the questions, but I am really excited about my first nitro car. I thank you all for taking the time to share your knowledge and experience.
Thank you,
Ben

One more quick question. What kinds of surfaces is it safe to run a car on? I know dirt, grass, and pavement are o.k. Is sand o.k.?I do not mean the beach but more like lower New Jersey were the ground is mostly made up of a hard packed sand. I am not sure how the car would handle in sand. Thank you again.
Ben

 

[SkyMaxx]

My first question is what kind of "car" did you get? That may help us in diagnosing some of the problems.

To answer your number two question, there are a couple of ways to handle that:
-You can trim the steerage out by using the trim dials, tabs, toggles (or whatever your radio uses). Just aply opposite trim while the radio and receiver are on and when the tires line up the way you want apply no more trim.
-You could turn on the radio and the receiver and see what the neutral position of the servo is without any trim applied; then unscrew the servo horn and put it on the hub of the servo in a way that the tires are straightened out. Then re-apply the screw that holds the horn in place.
-You could adjust the length of the linkage from servo to drag link. This would be my last option. I would go with my first recommendation for ease, then try the second, and if all else fails try the last.

As for the tuning instructions and smoke colors...every engine is going to require a slightly different variation on the same theme for breaking in the engine. Each manufacturer is going to have something specific for their engines. If you don't feel like you are getting the straight answer, contact the maker of your engine and ask them for the directions. As for smoke, when the engine is properly broken in and tuned correctly, you should see a steady stream of bluish white smoke. When you hit the gas, the volume of that smoke will increase, but even at idle you should see a slight smoky haze coming from the pipe.

As for safe surfaces to run on, you will need to answer my first question with regards to what type "car" you have. Then we can tell you if sand is a good place or not. Generally speaking, running on sand can be hazardous to your RC's health if you haven't properly set it up for running on sand.

Let us know...

 

[bigben]

The car is a Maximum Mt Pro buy duratrax. If the car is not meant to run in a sandy area how can it be setup to do so?
Thank you.
Ben

 

[SkyMaxx]

Things to consider when running in a sandy environment:
1. A really good air filter for the engine. You need something that will keep the sand and fine dust associated with sand from getting into the engine. If you have a good air filter, then you want to make sure that it is really securely fastened to the carb. If it comes off, your engine may be toast before you realize you have lost the filter.
2. Tires are real important for traction in sand. Depending on what you hope to do and how loose the sand is (wet sand is pretty hard, dry sand very loose), you will require different set of tires. Guys who run on sand fairly regularly usually buy a set of paddle tires, but something with a wide and deep tread pattern can accomplish the same thing. Bottom line is you need something that will dig in a little to give you the forward motion or else you will spend most of your time spinning your tires and throwing sand around.
3. An inline fuel filter is a must, especially if you are going to be refueling your truck in or around the sand. Sand getting into the engine through the fuel line is just as bad as through the air intake of the carb.
4. You might consider ballooning your servos (although not necessary) in order to minimize the amount of sand that might enter the servo. Sand and gears of any kind make for a mess.
5. If your truck has a tranny with any kind of access ports, you want to make sure the covers are securely in place. Again sand getting in there is bad.

These precautions are for running on a sandy surface like at the beach or a desert environment. If your sandy surface is a road that has loose dirt on it and that loose dirt is sandy in nature, then he only things you really need to get are a really good air filter and the in line fuel filter. The other stuff is more for running in the dunes.

As for the first question you asked in your original post, I'll let someone a little more familiar with the power plant and drive train on that truck answer the question. I have a few good ideas, and you could use them to start...but I will pass the buck to someone who knows that truck better.

The problems might be in the diffs or the tranny. The mesh might not be set up properly or something is slipping. If the weight of the truck is too much for the drive train to move (a bad thing as it is designed to move it rapidly), then there is something either broken or slipping in drive train. Based on what you said in your question, I'm going with something is slipping. There are a number of possibilities here...

 

[Hunter]

I have 1 question for you did you build this truck or buy it RTR new or used???

 

[bigben]

I must confess I purchased the RTR new. If I had built it myself I am sure I would have been able to figure out the front wheels being strait. I am completly new to Nitro R/C. This is the first real R/C car I have ever owned.

 

[SkyMaxx]

No problem...that is why places like this exist...we were all new to the hobby at one time or another...Ask your questions, and if we can help, we will.

 

[Hunter]

New is ok I'm thinking of your axle carriers thats why I asked. Ok it ran fine at first and the dog bones look good right??? So the next thing to check would be the axle carriers at the end of the a arms, see if the dog bones are going in all the way when you have the truck of the ground. Your looking for something that looks like a little cup with two slots cut in it.

 

[bigben]

The dog bones appear to go all the way into them.

 

[Hunter]

While your checking also check the top end near the trans for the same thing. This is for question #1 of your post.

 

[bigben]

I can see the shaft spinning fine weither it is on the ground or in the air. It will try to move a little but it is is as if it can't get enough power even though the shaft is spinning fine and the engine is not bogged down at all.

 

[Hunter]

At some point it is not hooking up to get the power to the wheels. If the shafts spin and the tires dont then the shafts are grabing where they should. Set your truck on a brick let the tires hang (off the ground) now spin the tires first one side then the other. Watch the dog bone while your doing this to see what happens. if the dog bones spin the next thing you do is spin the big gear this will take more time to do dut do it watching the dog bones turn. this will be the real slow part because of the gearing in the trans. Keep in mind if the DBs spin at the trans the problem has to be down the line some where. There is one other thing I just thought of there is a nut on the big gear next to the trans. this nut sets the friction of the sliper clutch it may need to be tightened up. Thats if the DBs are doing there job.

Oh did you ever pull the tires off your truck??? If you did was there a little peg in the steel shaft that the rim goes on and if so is it still there???

 

[El Pirata]

Not being very helpful in any way, but you paid $20 for them to tell you your engine was flooded. That's highway robbery! It's as bad as Hobbytown USA wanting to charge a very high paying customer to diagnos a product that they sold me. Now I shop very little as a result of this at Hobbytown.