Hints, tips and FAQ

[Mark Christopher]

I will put any thing that may be off use to IC drivers in here and eventually links to topics that reoccur on the board
If you wouild llike to have a link or some info posted on here email it to me



Clubs,tracks, Shops,manufactures and classes

Theses can all be found here www.brca.org by clicking the links, this is the governing body of our hobby/sport.

Items on here include

Tyre gluing

Cutting body holes

Hard to see hudy?

Engine set up

How DO i start my engine for the beginer

set up tips click me (http://www.mark.christopher.btinternet.co.uk/Setups/CAR.SETUPGUIDE.doc)

Glow plug info

[Mark Christopher]

Some drivers have trouble gluing their tyres to the wheels successfully.
follow this process and you will have no problems

1, clean the wheel and tyre well with either methylated spirits (purple stuff from hardware shops) or a alcohol such as isopohrol.
2, mount wheel to tyre and seat properly
3. i use a tool shown in the pictures this is by Tamiya but CML do one and they are available from your local model shop, if in doubt look in the CML catolgue



4,once in tool apply a good brand of super glue (take necessary precautions) and allow to dry, then repeat for the other side.



The main thing that MUST be done is clean the wheel/tyre well and get glue on the bead, not just the edge of the tyre and wheel.

If you need to remove any tyres the best method I have found is to use acetone, this dissolves the glue and leaves the wheel,tyre and insert intact NOTE you will need to test you wheels as some do melt!

[Mark Christopher]

Visit your local hobby shop or stationaries and buy a compass cutter. when you use it do not try to cut the hole out ,simply scribe it a few times, then cut from centre to the edge (carefully) with a hobby knife and then peel out

[Mark Christopher]

Do you have trouble seeing the etchings on your Hudy set up gauges?

To make them clearer do the following

Clear all your set up gauges well with methylated spirits
Take a good thin tip permanent marker and colour in the etchings, allow to dry.
Dampen a cloth with the meths and gently wipe Any excess colour off.

You can use different colours on the single line and the actual readings

[Mark Christopher]

Once a nitro engine has been run through several tanks during break-in process, it¡¦s

finally time to tune the engine for racing. Here are some tips when tuning engines.

Raise the idle about 1/2 a turn from where it was previously run. This is just to keep the

engine from stalling when I start going through my routine. Next, will fire up the engine ¡

§blipping¡¨ the throttle a few times until the engine is up to a reasonable temperature.

Some where in the 150 degrees
range. Now, richen the top end up a full turn. Holding the carburetor wide open and continue

to richen it up till the engine nearly stalls. If it does stall that is ok, just lean the

engine back in slightly so you can get it to re-start. Reason for doing this is to help

flush out any dirt or residue
(or after run oil) out of the carb and engine. Now that things are cleaned out and now can

begin to tune the engine to race trim.

First off, is to set the bottom end. To do this, carefully listen to the idle. If the idle

slows down and the engine stalls, lean out the bottom end needle.
If the idle speeds up then, richen up the bottom end needle. as much as possible until it

stalls.

From that point raise it back about 1/8 of a turn. The lower you can set the idle means

lower engine temperatures, better fuel mileage and better operation of your clutch since a

high rpm idle can slightly engage the clutch causing excessive heat and wear. Overall, your

engine should idle nice and consistent for at least 45+ seconds.

Next it¡¦s time for the fun part! The top end needle, where all that straight away speed and

power comes from. This is more of an adjustment for out on the race track but here¡¦s a way

to get it close on the bench.

Listen to the engine and lean it out until it sounds like it is achieving a nice clean

sound. This is a critical adjustment that will greatly decrease the life of your engine if

you get in a
hurry here so take your time. Once you get it to where you think it is close you have to

make sure that the engine won¡¦t lean bog or hesitate (say after a long straight, hard

braking and then hard acceleration to the next corner). Open the carb to full throttle for

2-3 seconds, then close the carb for 2-3 seconds, then back to full throttle for 2-3

seconds. Your engine should rev nice and clean through the 2nd full throttle blast. If it

hesitates at all then your engine is too lean and must be richened up on the top end needle.

Most importantly, listen to your engines. A lot of people fall into just watching the smoke

that comes from the exhaust and tuning the engines that way. This way is ok but if for some

reason you use different fuel (with different oil content
or mixtures) it becomes much more difficult to make your engines perform consistently from

race to race and in different weather conditions from just the sight of smoke. Learn how

your engine sounds and responds to your throttle input.

Good luck and have
fun!!!

[Mark Christopher]

Thanks to Kieth adamson for this!

Some basic help here to get your car started. Try this -

Make sure your glow starter is fully charged (that presumes it came with a charger, if it didn't, go back to your model shop and get one). In case you didn't know, the glow starter simply heats up the element of the plug to get the engine going. Once the engine is running you can remove it and the heat from the engine keeps the plug going.

Since you reckon you've flooded the engine, drain the fuel tank, remove the glow plug and turn the engine over a few times with the pull start to blow through the excess fuel.

While you've got the plug out, connect it to the glow starter and make sure the element glows. The idea here is to make the centre contact in the glow starter touch the top of the plug with the outer part clipped around the bottom (nut shaped part). If the plug doesn't glow either your glow starter is flat (shouldn't be if you've just charged it) or the plug is blown and you need a new one.

Assuming the plug glows OK, put it back in the engine and refill the fuel tank with whichever fuel you intend using to run the car. It should run happily on either 10 or 16 per cent fuel but 16% will give better performance.

Remove the pressure feed pipe (that's the flexible tubing that runs from the exhaust to the fuel tank) from the exhaust and blow gently through it to force some fuel into the carb then reconnect the pressure feed.

Put your car on a stand or suitable alternative to keep the wheels off the ground. Connect your glow starter to the glow plug. Switch on the radio and car.

Pull fairly vigorously on the pull start a few times and hopefully the engine will burst into life. This is not a test of strength, try and keep your pulls fairly quick but stop just short of the maximum travel.

Assuming the engine starts, blip the throttle control on the radio a few times to warm it up, remove the glow starter from the plug and then follow the advice others have given on running in.

If none of this works, there are so many variables that could be wrong it's really difficult to diagnose remotely. Either get help from somebody with a bit of experience or take it back to your model shop and get them to sort it out.

Sorry if this sounds a bit patronising but it can be difficult to judge how much or little you already know.

[Mark Christopher]

Heat range :
Since the engine’s timing is dependent on the size of the element in the glowplug, it has become very important to choose the correct heat range glowplug for a given engine.

Turbo plugs are a type of plug with a cone shaped seat that fits into a specially designed head insert.

They require no extra sealing washer and have been proven to increase power over the entire

power-band of the engine. They are available in ranges of numbers 5 through 8. In most brands, they are even further subdivided as “C”-hotter or “F”-colder. If you don’t speak Italian or Spanish in those languages, C stands for Caliente (hot), and F stands for Frio (cold) then the easiest way to remember is that “F” is associated with freezing, therefore it stands for cold). So you have, in order from hottest to coldest, 5TC, 5TF, 6TC, down to 8TF.

Standard plugs fit most engines. They require a copper-sealing ring, and are available in heat ranges from 5 through 9, with 9 being the coldest. While these plugs are substantially different, the same basic principles apply to both types of glowplug.

Using different HEAT RANGE plugs controls glow plug temperature. Just like motorcar spark plugs, glow plugs come in different heat ranges from hot to cold with maybe half a dozen steps in between. If in doubt, use the plug specified by the engine manufacturer. Using a hotter plug than normal will advance the ignition point and a colder plug will retard the ignition. The only way to determine exactly the right heat range plug is by using an accurate tachometer. The plug that gives the highest rpm (for the same fuel and propeller) is the correct plug.

What about the pressure of the fuel/ air mixture? This is determined by the compression ratio of the engine and normally is fixed by the manufacturer with possibly some small change allowed for by fitting or removing shims under the cylinder head. Not something to play with unless you know what you are doing.

The thickness of the glow wire will make the difference between a HOT, MEDIUM or COLD. Each manufacturer offers a range of plugs; a plug is usually identified by a code that indicates its effective operating temperature; not the operating temperature of the engine or the outside air, but the relative temperature of the glow plugs coil. Each manufacturer has its own unique temperature rating system; the process can be confusing, however, because a universal rating system does not exist for glow plugs. So what should you look for in a replacement plug?

Some general rules about plugs are determined by the size of the engine and the type of fuel used:

Smaller engines “usually” require hotter plugs, while larger engines favor cooler plugs. Engines that run fuel containing a “high percentage of nitro favor the cooler plugs” as well, while those that run on “less nitro prefer hotter plugs” (nitro fuels for car engines typically include 10 to 25 percent nitro methane).

For example, a small, .12 Size engine that burns high-nitro fuel would favor a warm plug in a mid-range temperature (small engine = hotter plug; high-nitro fuel = colder plug).

The same plug might also be suitable for a .21 Size engine running low-nitro fuel (large engine = colder plug; low-nitro fuel = hotter plug).

The size of your engine and the type of fuel are easy enough to determine, so these guidelines

should get you pointed in the right direction. For racing nuts who want to get maximum power, however, another element that’s not easily determined—yet should be taken into consideration—is compression ratio. The compression ratio of an engine will also be a factor in choosing the proper plug. “High-compression” engines favor colder plugs, while those with lower compression favor hotter plugs. Engine manufacturers rarely disclose an engine’s compression ratio, so it may be difficult to use this information to select plugs unless you know how to calculate compression or can measure it with a compression gauge.

What makes the subject of choosing a glow plug a little confusing is the variety of types that

available. Each manufacturer offers a range of plugs, from as few as three or four up to 10 or more.

A plug is usually identified by a code that indicates its effective operating temperature, not the operating temperature of the engine or the outside air, but the relative temperature of the

Glow plugs coil. Each manufacturer has its own unique recommendations are sometimes included to try to steer consumers towards the correct plugs for their needs. The process can be confusing ,however, because a universal rating system does not exist for glow plugs. For example, an O.S. R5 plug is not the same as a McCoy MC-9, although both are considered “ cold” plugs.

Nitro percentage:
Now that the engine is running decently, what changes to the plugs have to be made if the nitro percentage is increased?

To do this you need to understand a little more of the theory behind the process. In glow fuel the catalytic reaction is generated between the methanol and platinum only. Castor oil, synthetic oil, nitro methane etc do not generate a catalytic reaction with the platinum.

Next you need to understand that a certain surface area of platinum is required to generate a

Sufficient catalytic reaction to keep the internal combustion process going. Also it is necessary to allow extra surface area for the reaction to be great enough when it diminishes with the available methanol dropping as in the case at motor idle. Simply put, cold plugs are manufactured using a thicker wire to give greater surface area to facilitate a greater and thus the required catalytic reaction where less methanol is present in the fuel mixture.

So! More nitro means less methanol, which in turn means a greater surface area to platinum will be required to generate a sufficient catalytic reaction.

Suddenly it all makes sense! To work out which temperature plug to use, you need to know how much methanol is in your fuel, not how much nitro or oil.



As a rough rule of thumb;

· 80%: methanol or above, use a hot plug.

· 70%-75%: use a medium plug.

· 60%-75%: use a cold plug.

· 65% or less: use a very cold plug.

· Nitro-methane burns hotter than methanol, the other principal ingredient in fuel. Because

of the additional heat, which is produced when changing to a higher nitro content fuel, the

easiest way for a glowplug to withstand this higher heat is to change to a glowplug that uses

a thicker element, in other words, a “ colder plug” .



· For engines with a nitro percentage below 10% a HOT plug will do OK when the outside temp is between 59- 68 Deg. Fahrenheit.

· For engines with a nitro percentage between 10 and 25% a MEDIUM or COLD plug will do OK when the outside temp is 59- 68 Deg. Fahrenheit.

· For engines with a nitro percentage above 25% (for fools only) a COLD plug will do OK when the outside temp is59- 68 Deg. Fahrenheit .

A lot of testing and experience has yielded the following formula that seems to work pretty well.For every 10% increase in nitro over what is normally used, a corresponding change in plugs of one range colder is required. So if the engine is running well with 30% using a 6TF plug, then it will probably make more power at 40% using a 7TF plug providing that the weather hasn’t changed too much, and provided that the head clearance has been adjusted properly.



Exhaust pipes:

The third item to consider is the effect of pipe length on the glow plug. After some runtime, the plug’s condition will determine the proper pipe length. If the element is pushed up inside, then a hotter plug is required or the pipe should be lengthened. If the element is gone, then the oppositesare true - use a colder plug or a shorter pipe.



What happens if you use the wrong plug?


If you have used a plug that is too hot or too cold for your application, this will be revealed in one of two ways. If the plug is too hot, the engine may suffer from detonation, pre-ignition and high running temperatures. Detonation occurs when the fuel mixture explodes quickly rather than burns. You don’t want this to happen because it can damage the engine.

The telltale signs of detonation are a “miss” in the exhaust tone at high speeds and a pitting of the cylinder head around the glow plug and the top of the piston. Severe detonation can cause the coil element of the glow plug to come loose, and this can severely damage the engine. The primary cause of detonation, however, is excessive compression. Simply using a hot plug will not usually cause detonation; so don’t be afraid to experiment. If you’re using high-nitro fuel and have increased the compression by reducing head clearance, however, a hotter plug may just push the engine too far and cause damage.

At the very least, an excessively hot plug will cause pre-ignition, in which the fuel mixture begins burning well before the piston reaches the top of the cylinder.

Using a plug that is too cold will result in a loss of acceleration and top speed and will cause poor engine idle. If the plug is much colder than it should be, you might notice an excessive raw-fuel discharge from the exhaust pipe. Don’t confuse this with an excessively rich fuel mixture.



What makes a glowplug hotter or colder?



Many elements influence a glow plugs temperature range, but primary is the thickness, length and composition of the wire used to form the coil. Other factors that affect a glow plugs temperature include the size of the hole in which the wire is installed; the type of plating used on the glow plug.



Plug conditions

The term “ reading a plug” is commonly heard in the pits, but how is this done? In addition to the conditions that have been previously mentioned, the plug should be visually inspected for color.

The simplest accessory to check is the glow plug but it is also the one that gives you the exact image of the engine health. The thread is silver color but is made with an alloy composed by Platinum and Rhodium! To keep a constant look at glow plug will help you to understand How To make the carburetion. In the following way:

Take the glowplug away and look at the thread:



· If the thread has a dark colour and the plug seems humid, the carburetion is too rich and

the engine does not work at its best. You have to lean the carburetion closing the full speed

needle.



· If the plug body (the part surrounding the element) is wet and the element is shiny, and in its original location, then change to a “colder plug” (assuming that your engine temperature is on the cool side).



· If the plug body is dry, and the element is shiny, the plug is correct for the conditions.



· If the spiral of the plug is a little bit pressed and bent it means that the engine has too

much compression. If you are racing on a sea level track, with 25% or more nitro could be the main reason. Than you need to check under head shims and in such a case insert a tenth.

· If the plug body is dry, and the element is a dull grey, the engine is running too lean -

change to a “ hotter plug” to correct the condition.



· If the thread has a dull, as sanded, it means that the carburetion is too lean (poor of fuel)

and you can damage the engine. You run the risk to break the thread and to make it fall

down on the top end of the piston, damaging also the sleeve. In both these cases, we

suggest you to replace the old with a new plug.

Apart from when actually burned out, a plug may need to be replaced because it no longer delivers its best performance, such as when:

· Filament coil has become distorted.

· Filament surface has roughened while.

· Foreign matter had adhered to filament or plug body has corroded. Engine tends to cut out

when idling.

· Starting qualities deteriorate.



Rules of thumb.

You can only “ Read” your plug in a nearly new state [Wire like new and shiny] a grey plug can still operate well. But after it has totally gone grey performance can start to fall off. To test just put in a new plug and if there is no difference in performance save the gray one or put it back in. If your engine does not feel or run right away a new plug before making major tune changes.

· Wire and surrounding bottom of plug wet, with like new shiny wire = rich side of optimum power 85%

· Wire and surrounding bottom of plug starting to dry and wire starting to gray = Very close

to optimum power 95%

· Wire and surrounding bottom of plug dry, wire totally gray but not distorted optimum

power 100%

· Wire and surrounding bottom of plug dry, wire distorted = slightly lean DANGER

· Wire and surrounding bottom of plug dry, wire broken and distorted or burnt up =

extremely lean possible engine damage!

For ultimate power a competition modeler will juggle combinations of plug, compressions and type of fuel (mainly nitro methane content) but this is way beyond the needs of the normal driver.









The pro’s best kept tuning secrets

One of the best-kept secrets of the most experienced nitro racers and engine tuners is that you can net some serious horsepower gains by experimenting with various glow plugs.

As mentioned earlier, a glow plug is the ignition system for a nitro engine.

Anyone who has ever worked with spark-ignition systems knows that ignition timing can have a profound effect on engine performance. “ Ignition timing” is when the fuel mixture is ignited in relation to the position of the piston and crankshaft during the compression stroke.

When the piston is at top deal centre (TDC) of the cylinder, the crankshaft’s journal, to which the connecting rod is attached, is pointing straight up. This puts the piston at the highest point of its travel in the cylinder; therefore, the crankshaft is at “ zero” degrees. The crankshaft must rotate a full 360 degrees to make a full cycle, so the amount of crankshaft rotation in degrees is used to measure the events that take place inside the engine; for example, ports opening and closing and ignition. Although you can’t measure or definitively set when ignition takes place inside a nitro engine, it helps to be able to visualize what’s happening when you experiment with different plugs.



Many thanks to Denis Richey for this article