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behappy2755

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Posts posted by behappy2755

  1. I'm looking for two small, high speed servos, 0.07 s/60degrees or less. These will go on top of a rocket to act as controlling fins, so the torque shouldn't really matter. Any ideas?? 

  2. 2 hours ago, locky said:

     

    There should be a shaft in the middle of the backplate onto which the one way bearing slides and then the pull start.

     

    Yes, this one. Its not very new, the engine has had nearly 2L through it. I have stripped it quite a few times in the past, sealing everything up properly apart from the moving parts.

     

    And if you take the carb off and look down the hole, you can see the crankshaft, which opens up on the upward stroke. Then it closes and the piston goes down, and the pressure escapes around that opening on the crankshaft (which is facing down at this moment) and around the wall which holds it, up into the carb hole.

  3. Its a FTX Go.18, stock from the carnage NT. All the joints are well sealed, apart from the hole in the engine back plate where the crankshaft pokes through, and the around the port under the carb (not the carb seal itself). The front bearing where the flywheel is doesn't leak. Would the sealant work in the moving parts? I'm sure it would rip off at high speed and fall into the crankcase!

  4. The crankshaft in my engine is leaking out the back of the engine into the pullstart at high pressures (which means I get covered in fuel and green goo from the pullstart when I pull on it). Also,at higher temperatures, air leaks back out of the rotating port under the carb, around the side of the case and back up. This in turn restricts fuel flow as the pressure pushes it back. I don't fancy paying loads of money for a new crank, might even need a new case which means it would be better just to buy a new engine. Is there a magic way to seal it with something? 

  5. Heat the engine up, with a heat gun or hair dryer, and prime properly (make sure the fuel tank is full and that fuel is flowing down the line). Then give it an extra 5 pulls without covering the exhaust. Open the idle gap, and attempt to start it with a few quick pulls. Is your fuel fresh? Does the glow plug actually glow when you take it out?

  6. Its a little disk that goes between the top of the piston sleve, and the engine head where your glow plug screws in. Some people decide to add a couple extra to make the chamber slightly bigger.

     

    If the parts look clean and there aren't any major cracks or bends, you could maybe try adding a tiny folded piece of aluminium foil between the engine head and the cooling head on the side that its leaking on to press it down more?

     

    EDIT:

    I'm not familiar with the DT-10, and from that instruction thing it looks like your glow plug just screws into the cooling head which also acts as the engine head, so that aluminium thing wouldnt work.

  7. Do you have a burn room washer(s)? The whole assembly should fit closely even without screws. If the parts are faulty it would be difficult to do a quick seal job with some ol' goo because of the temerature and pressure; you might have to buy parts.

     

    Also, its surprising that you say fuel is leaking as the highest pressure is caused by the combustion, so its more likely to have been smoke? If its on the carb side of the engine, you should also check the carb.

  8. I the carb was stuck to I had to take the whole bloody engine apart to get to it with a wrench, I was playing around with the flywheel making the cylinder go up and down :mf_laughbounce: (the only good thing about an engine strip) when I noticed that there was a squeak coming from the front of the engine block during the downward stroke before the ports opened (the carb was still on at this point). The crankshaft port is closed at this point, but maybe the pressure is escaping around the side of the crankcase and up into the carb??  As the engine gets hotter, this fault might expand, which fits in with the other problems?? What would be the best solution; new crankshaft and/or engine block, or some trick to eliminate the gap like a sealant or whatever?

  9. Yeah the tank seal is fine, I remember a new tank was the first part that I bought. Yesterday I took the fuel line off the carb, and primed the engine with a blocked exhaust and loads of fuel came shooting out onto the floor. I think it must be some sort of overheating problem?

  10. Hello, being bored from revision I had the idea to go to my garage and try to fire up my old Carnage NT after at least a year of it waiting patiently on the bench. I was surprised how well it performed, but I can remember it cutting out quite a bit as it did today. It seems as if the fuel is retreating down the fuel line away from the carb and back into the tank, which I believe is due to a higher pressure in the carb than the tank. Overall, the best tuning i could get was very rich, clouds of blue smoke, and it worked quite well at up to half throttle. Whenever I opened the throttle fully (either gently or sharply) the car would bog and die, or sometimes just cut. Today it even made a weird noise with quick, loud revving intervals. I thought it might be a lack of air, so I took the air filter off and drove around with an open carb for a little while, but the same happened. If I run it leaner, the fuel bubble doesn't reach the carb, this effect goes away if I let the car sit for 2 minutes with the engine off (maybe too hot?).

    i remember fighting this problem a lot, any ideas??

  11. Not massively so, have you ever felt how heavy a racing car's wheel actually is? It would only be a couple of extra kg, which they can then take out of the ballast they put in anyway. So actual weight change would be negligible 

     

    And also, If they put in the 6 extra pit crew or so, It wouldn't add any time, just more chance of time being added. If that makes sense.

    Well, extra brake disks and calipers, wheel hubs, differentials, suspension arms and springs, and the steering mechanism for 4 wheels might make a slight difference to weight. But I agree with you that the wheels only would not really affect it.

     

    And also... It would be harder to change the tyres in a busy space especially when passing the new tyres and taking the old ones away. 

     

    Another problem would be that you would have to have very soft differentials for the front wheels, which would mean you would need to do that also for the rear to eliminate the huge over-steer.

  12. You know there was a F1 car like that?....maybe one day it will happen again...who knows. :)

    http://en.wikipedia.org/wiki/Tyrrell_Racing#mediaviewer/File:ScheckterJody1976-07-31Tyrrell-FordP34.jpg

    Oh. I never knew. 

    I read that it was developed to reduce aerodynamic drag of the front wheels, increase the road to tyre area, and spread out the brakes. But today brakes and tyres are good anyway, and this design would only cause steering problems as the wheels would want to spin at different rates, not mentioning it would make the pit-stop time longer!

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