Willmann Racing Products - Tech Information

Technical Information

Modified motors by ESP.

WRP can now order top of line quality Earth Surfer Products engine's and parts. Increase the performance of your motor with these top-of-the line items. You can now order Engines with hp ratings of 3.75 and up to the killer of 4.5 hp. Head kits are also avaible for that increase of hp. We can install head kits on the 230RC or 260RC or if you are handy with tools, you can install right at home. As a past user of ESP Motors I can tell you from exprience that these motors are killers. Using the ESP motors in the Mod Class racing Quads, I have broke records at Wacha's Place Speedway and winning number of features. For the QSAC racer, these are NOT LEGAL under QSAC guidelines. Coming in the next few weeks WPR will have a new online site to buy these motor direct, but for now call me for motor prices.

Cheaper and Fastest Way of Shipping Motors Back to WRP.

Have you ever wonder how to save shipping chargers when you ship a motor back for repairs. WRP use the Flat Rate priority Mail at your local post office. Box's are FREE when ship Priority. For a price of $8.95 you can ship a motor back to me. Check UPS and Fed-Ex prices and then check USPS. Remember you must ask for Priority Mail to receive the free box. Now you can have delivery of documents and packages made in an average of 2 to 3 days. Low flat-rate shipping is also available with Priority Mail for any destination and any weight up to a 70 lb. maximum when you use either Flat Rate Envelopes or Flat Rate Boxes.

Priority Mail® Features

Expedited delivery of your packages at economical rates, starting at $4.60

Packages are delivered in an average of 2-3 days to any destination.

Delivery to all U.S. addresses, including PO boxes and military addresses.

Understanding AMSOIL 2 - Stroke Oil.

New AMSOIL Saber Professional Synthetic 2-Cycle Oil is specifically designed for lean mix ratios in pre-mix applications. Saber Professional contains high temperature detergents for small power equipment. Extensive testing shows superior lubricity and cleanliness properties at lean mix ratios with this premium synthetic formulation.

Saber Professional is "Smokeless"
At 100:1, produces 30 percent lower emissions than oils mixed at 50:1
Saber Professional is recommended for ISO-L-EGD applications
One mix ratio for everything eliminates confusion
Versatile and very good for many applications
Cost effective compared to oils mixed at 50:1 or richer
Saber Outboard exhibits low aquatic toxicity
Lean mix ratio prevents plug fouling and exhaust port deposits

Products Description

AMSOIL Saber Professional Synthetic 100:1 Pre-Mix 2-Cycle Oils are formulated with exclusive AMSOIL synthetic base oils and premium additives. Designed for lean mix ratios in two-cycle motors, Saber 2-Cycle Oil has excellent lubricity and cleanliness properties, controlling friction and preventing wear, plug fouling, ring sticking and exhaust port blocking. AMSOIL Synthetic 100:1 2-Cycle Oils have been protecting and providing improved performance in two-cycle motors since 1973.

Saber Professional

Saber Professional (ATP) is specifically designed for small engines including, but not limited to, chain saws, lawn equipment, blowers, chop saws, pumps, scooters and go-carts. It is also very good for use in motorcycles, snowmobiles, ATVs, jet boats and personal watercraft. Saber Professional is formulated with high temperature detergent additives that prevent hard carbon deposits from forming in these hot operating motors. Saber Professional is "smokeless" and delivers as much as 30 percent fewer emissions at 100:1 mix ratios than oils mixed at 50:1. Equipment operators subjected to smoke and fumes will benefit from these low emission properties. Because one mix ratio satisfies multiple pieces of equipment, Saber Professional eliminates mix ratio confusion. Saber Professional is recommended for pre-mix where ISO-L-EGD, JASO FC or API TC is specified.

Applications

AMSOIL Saber 100:1 2-Cycle Oil is recommended for 100:1 mix ratios in normal service and 50:1 to 80:1 mix ratios in severe service applications such as commercial equipment operations and racing. WRP Recommends using 2 oz per gal. or 64:1 for better cooling and top performance of your race motor. WRP is your full service AMSOIL Dealer from top of line Motor oil for your car/truck to your race motor.

Understanding Spark Plugs

Spark plugs are one of the most misunderstood components of an engine. Numerous questions have surfaced over the years, leaving many people confused. This guide is designed to assist the technician, hobbyist, or race mechanics in understanding, using, and troubleshooting spark plugs. The information contained in this guide applies to all types of internal combustion engines.

Spark plugs are the "window" into the engine , and can be used as a valuable diagnostic tool. Like a patient's thermometer, the spark plug displays symptoms and conditions of the engine. The experienced tuner can analyze these symptoms to track down the root cause of many problems, or determine air/fuel ratios.

Spark Plug Basics

The spark plug has two primary functions:

Ignite air/fuel mixture

Transfer heat from the combustion chamber

Spark plugs carry electrical energy and turn fuel into working energy. A sufficient amount of voltage must be supplied by the ignition system to spark across the spark plug's gap. This is called "Electrical Performance."

The temperature of the spark plug's firing end must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. This is called "Thermal Performance", and is determined by the heat range selected.

It's important to remember spark plugs do not create heat, they only remove heat. The spark plug works as a heat exchangerby pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine's cooling system. The heat range is defined as a plug's ability to dissipate heat.

The rate of heat transfer is determined by:

The insulator nose length

Gas volume around the insulator nose

The materials/construction of the center electrode and porcelain insulator

A spark plug's heat range has no relationship to the actual voltage transferred through the spark plug. Rather, the heat range is a measure of the spark plug's ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors; the length of the ceramic center insulator nose and its' ability to absorb and transfer combustion heat, the material composition of the insulator and center electrode material.

Heat rating and heat flow path of the Spark Plugs

The insulator nose length is the distance from the firing tip of the insulator to the point where insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. Whether the spark plugs are fitted in a lawnmower, boat, or a race car, the spark plug tip temperature must remain between 500C-850°C. If the tip temperature is lower than 500°C, the insulator area surrounding the center electrode will not be hot enough to burn off carbon and combustion chamber deposits. These accumulated deposits can result in spark plug fouling leading to misfire. If the tip temperature is higher than 850°C the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition/detonation and expensive engine damage. In identical spark plug types, the difference from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing tip temperature is increased by 10°C to 20°C.

The firing end appearance also depends on the spark plugs tip temperature. There are three basic diagnostic criteria for spark plugs: good, fouled and overheated. The borderline between the fouling and optimum operating regions (500&def;C) is called the spark plug self-cleaning temperature. The temperature at this point is where the accumulated carbon and combustion deposits are burned off.

Keep in mind the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water jackets. This means the plug has a higher internal temperature, and is said to be a hot plug hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.

Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range is necessary when the engine is modified for performance, subjected to heavy loads, or is run at a high rpm for a significant period of time. Colder spark plugs remove heat quicker, reducing the chance of pre-ignition/detonation. Failure to use a cooler heat range in a modified application can lead to spark plug failure and severe engine damage.

Below is a list of external influences on a spark plug's operating temperature. The following symptoms or conditions may have an effect on the actual temperature of the spark plug. The spark plug cannot create these conditions, but it must be able to cope with the levels of heat...if not, the performance will suffer and engine damage can occur.

Air/Fuel Mixtures

Seriously affects engine performance and spark plug operating temperatures. Rich air/fuel mixtures cause tip temperature to drop, causing fouling and poor driveability. Lean air/fuel mixtures cause plug tip and cylinder temperature to increase, resulting in pre-ignition, detonation, and possibly serious spark plug and engine damage. It is important to read spark plugs many times during the tuning process to achieve the optimum air/fuel mixture.

Higher Compression Ratios/Forced Induction

Elevates spark plug tip and in-cylinder temperatures. Compression can be increased by performing any one of the following modifications:

Reducing combustion chamber volume (i.e.: domed pistons, smaller chamber heads, milling heads, etc.)

Adding forced induction (Nitrous, Turbocharging or Supercharging)

Camshaft change

As compression increases, a colder heat range plug, higher fuel octane, and careful attention to ignition timing and air/fuel ratios are necessary. Failure to select a colder spark plug can lead to spark plug/engine damage

Advancing Ignition Timing

Advancing ignition timing by 10° causes tip temperature to increase by approx. 70°-100° C

Engine Speed and Load

Increases in firing-end temperature are proportional to engine speed and load. When traveling at a consistent high rate of speed, or carrying/pushing very heavy loads, a colder heat range spark plug should be installed.

Ambient Air Temperature

As air temperature falls, air density/air volume becomes greater, resulting in leaner air/fuel mixtures. This creates higher cylinder pressures/temperatures and causes an increase in the spark plug's tip temperature. So, fuel delivery should be increased. As temperature increases, air density decreases, as does intake volume, fuel delivery should be decreased.

Humidity

As humidity increases, air intake volume decreases. Result is lower combustion pressures and temperatures, causing a decrease in the spark plug's temperature and a reduction in available power. Air/fuel mixture should be leaner, depending upon ambient temperature.

Barometric Pressure/Altitude

Also affects the spark plug's tip temperature. The higher the altitude, the lower cylinder pressure becomes. As the cylinder temperature decreases, so does the plugs tip temperature. Many mechanics attempt to "chase" tuning by changing spark plug heat ranges. The real answer is to adjust air/fuel mixtures by rejetting in an effort to put more air back into the engine.

Types of Abnormal Combustion

Pre-ignition

Defined as: ignition of the air/fuel mixture before the pre-set ignition timing mark.

Caused by hot spots in the combustion chamber...can be caused(or amplified) by over advanced timing, too hot a spark plug, low octane fuel, lean air/fuel mixture, too high compression, or insufficient engine cooling.

A change to a higher octane fuel, a colder plug, richer fuel mixture, or lower compression may be in order.

You may also need to retard ignition timing, and check vehicle's cooling system.

Pre-ignition usually leads to detonation; pre-ignition an detonation are two separate events.

Detonation

The spark plug's worst enemy! (Besides fouling).
Can break insulators or break off ground electrodes.
Pre-ignition most often leads to detonation.
Plug tip temperatures can spike to over 3000°F during the combustion process (in a racing engine).
Most frequently caused by hot spots in the combustion chamber. Hot spots will allow the air/fuel mixture to pre-ignite. As the piston is being forced upward by mechanical action of the connecting rod, the pre-ignited explosion will try to force the piston downward. If the piston can't go up (because of the force of the premature explosion) and it can't go down (because of the upward mo-tion of the connecting rod), the piston will rattle from side to side. The resulting shock wave causes an audible pinging sound. This is detonation.
Most of the damage than an engine sustains when "detonating" is from excessive heat.
The spark plug is damaged by both the elevated temperatures and the accompanying shock wave, or concussion.

Misfires

A spark plug is said to have misfired when enough voltage has not been delivered to light off all fuel present in the combustion chamber at the proper moment of the power stroke (a few degrees before top dead center).
A spark plug can deliver a weak spark (or no spark at all) for a variety of reasons...defective coil, too much compression with incorrect plug gap, dry fouled or wet fouled spark plugs, insufficient ignition timing, etc.
Slight misfires can cause a loss of performance for obvious reasons (if fuel is not lit, no energy is be-ing created).
Severe misfires will cause poor fuel economy, poor driveability, and can lead to engine damage.

Fouling

Will occur when spark plug tip temperature is insufficient to burn off carbon, fuel, oil or other deposits.
Will cause spark to leach to metal shell...no spark across plug gap will cause a misfire.
Wet-fouled spark plugs must be changed...spark plugs will not fire.
Dry-fouled spark plugs can sometimes be cleaned by bringing engine up to operating temperature.
Before changing fouled spark plugs, be sure to eliminate root cause of fouling.

Understanding the numbers on the plugs

R stands for resistor which is use in all RC cars, trucks, planes and boats. I like to use a grounding wire from the engine case to the frame of the car to ground the motor.

If you are running the NGK Irdidium plug cr8hix or cr7hix heat range goes follows:

cr7hix - This is a Hot plug. It has a larger surface exposed to the combustion gasses. It dissapates the heat slowly. Its firing end heats up quickly.

cr8hix - This is a Cold plug. It has smaller surface exposed to the combustion gasses. It dissipates heat quickly. Its firing end does not heat up quickly.

Installing your QSAC Plate

QSAC plate will fit the old style or the new 230RC manifold.