Newbie intro & Question

[Alfsdad]

Hi all,

 

I’m new to all this, hoping to get more knowledge. I recently purchased an RC nitro condor build your own kit as a project for me and my son. 
 

having built it I had a nightmare trying to get it going, broke the pull starter, so replaced it with an electric one. From there it all went wrong, I managed to snap the spray bearing clean in half. It’s now been built for a week and yet to even hear the sound of the engine lol. 
 

I can’t for the life of me work out how I did that, one thing I have noticed is that the piston is sticking when it gets to the top, I’m assuming this isn’t normal, but just wanted to check. Anyone have any ideas? 
 

many thanks in advance. 

[J.K]

The piston sticking at the top is the "pinch" where the cylinder gets slightly narrower to help create the compression. On a new engine this pinch is tight and will loosen as the engine is used. You need to heat the engine up as much as you can when it's new to help starting. A hairdryer on the hottest setting for a good 10mins should help

[Alfsdad]

Brill, cheers guys. 

[J.K]

2 minutes ago, 1111 said:

 Using a hair dryer is a waste of time. 

 

Not in my experience. The warmer the engine the easier it is to start. Doesn't hurt, does it?

[J.K]

6 minutes ago, 1111 said:

 YES ! In 10 minutes I could have had the engine started . No hair dryer required. Heating is only good for winter starting a cold engine. I don't even do that. If using heat use a heat gun.

 

A new engine is tight. Hence the OP is having issues with his new engine getting stuck at TDC. Metal expands with heat, hence heating it will make it easier to start. Why do racers use engine heaters? Are they wrong too?

 

I said heating an engine doesn't hurt and you said YES!!!! Why? Any evidence?

[MacRaguel]

Befriend your local hobby shop, get them to have a look and talk you through what they found 

I’m also new to this and building a kit, some parts do want that pro eye over....itll save you money in the long run, you’ll learn faster, you’ll enjoy your car more

[Alfsdad]

Hi all. 

thanks for the guidance. So I’ve just tried turning it over with the glow undone a bit, turns lovely but won’t start. Tried tightening the plug again, just keeps getting stuck but almost starting. 

I did contact the only local shop this morning to source a spare part, but they weren’t very helpful, kinda rude about my “cheap” car. (It probably is cheap to experts, but wasn’t to a newbie like me). Shan’t be speaking to them again. 

 

[Shudson]

4 hours ago, J.K said:

 

A new engine is tight. Hence the OP is having issues with his new engine getting stuck at TDC. Metal expands with heat, hence heating it will make it easier to start. Why do racers use engine heaters? Are they wrong too?

 

I said heating an engine doesn't hurt and you said YES!!!! Why? Any evidence?

I have been playing with model engines for 60 years, initially  with boats, when I  won a number of  championships, including speed, and subsequently with planes, cars and almost anything  that uses them, and have never found it necessary.  I suppose that, if it keeps you amused twiddling your thumbs while you heat an engine, then I suppose fair enough. However, as to whether or not it can do any harm, I suppose it is a question of degree - what is the worst thing that you can do to an engine and that will guarantee its early demise? Running it too hot when it will ultimately seize up. Rather defeats the argument that heating frees it up. However, heating a badly worn engine, and running it hot, can make it usable for a little longer, because it seals better.

 

To revert to your comment about expansion, that does rather depend on the construction of the engine.  In the early days the cylinder was usually machined from cast iron, frequently with an aluminium or light alloy piston. This was OK for smaller engines, but in my boating days, our larger 10cc (.60 cu in.) racing engines had to use ringed pistons to accommodate the differing coefficents of expansion. Then came the ABC (Aluminium/Brass (or Bronze)/Chrome) cylinder/piston construction used by most modern engines, certainly with any claim for performance. This uses an aluminium or light alloy piston, Brass or Bronze cylinder with a Chrome plating to reduce wear and carefully matched coefficients of expansion to preserve the "fit" throughout a range of temperature.  This rather defeats your heating argument.

 

As to why racers use engine heaters, not being a racer, or other competitor these days, I cannot really say. However, in my competitive boating days when I suppose I was one of the "elite" and certainly mixed in "elite" circles, for many it was essential to have the latest (and most expensive) gadgets and kit, without any thought of whether or not it was effective. Part of being the best, it was presumably thought that you had to have the "best", or better still, the most expensive.

 

Just as a final poser on the heating/expansion question, imagine taking a piece of metal and drilling a hole in it. If you heat up the piece of metal, does the hole get larger or smaller?

[omega1]

Just to add my limited experience regarding the engine not starting and having to heat the engine, I  found that if I do not pre-heat mine, it will simply not start at all. I purchased one of these and the problem went away and started pretty much straight away