The 2013 racing season is starting and in all of the confusion created in getting the car ready, we might overlook some important engine-related items. Here are 10 tips that can help you keep going and avoid engine stoppages and failures as the year progresses. Some of these might be new to you and some might be old hat. Nevertheless, it is always a good idea to review our procedures each year so we don't forget important information.
I've worked with many different teams and there is always something coming up that surprises the crew. Simple things like a bad “new” spark plug or buying great used oil lines only to find out that the last engine the lines were installed on blew up leaving bits and pieces embedded in the lines. Or wires crossed on the MSD ignition that caused an awful rattle in the motor. No, the blue and purple wires do not go together on the older systems.
To avoid all of those problems, we need to learn from the experts who probably made these same mistakes at some point in their careers or has knowledge of someone who did. Many of these tips may seem simple stupid, but some may surprise you. Take it all in and apply what is applicable to your particular type of racing.
Check your timing often. If the timing is erratic or changes unexpectedly, then search for
Always check your timing at the track and before you run the car. There are several things that can cause the timing to change. A worn distributor gear is one of those and that can happen during one race, the last one.
Loose distributor lock down bolts are another area where the vibrations of racing will undo many connections and bolts that may not have an impact on your engine, but with the distributor, any slight movement of the housing will seriously affect your timing and power.
Secure your plug wires to prevent them from moving around. Excess movement causes the wire
2. Plug Wires and Plugs
Purchase a wire tester specifically for plug wires and use it often. Many times a loss of power can be traced to a faulty plug and/or distributor wire. Let's face it, the wires are under a lot of stress. Not only do they pass along high electrical loads, they bounce around a lot, especially in dirt racing when the track is rough.
As you are testing the wires, move them around by bending and twisting them. Some wires could be compromised to the extent that in one position they will test OK while in another they will test bad.
Plugs too can be bad, even new ones. If you have installed a new set of plugs and the engine misses, immediately do the plug wire one-at-a-time removal to find a possible bad plug. It has happened and will happen again. Always check the gap on your plugs before installing them.
3. Valve Gap and Springs
With high rpm built motors, the valvetrain is under a lot of stress. Wear occurs all along the way from the cam to the valve seats. Minute wear and stress stretching does change the clearance from the rocker to the valve stem.
Recheck and reset the valve clearance often on these types of motors. While you are under the valve covers, inspect for broken springs, cracked rockers and problems with the retainers. It's also a good idea to remove and check the spring rate on the valvesprings every five races or so. Do this in the shop where the environment is sanitary.
4. Timing Chain and Sprockets
At least yearly, check the timing chain for stretch and wear along with the sprockets. Short-term events like an overheated motor can affect many parts and the timing chain can be similarly affected and go unnoticed.
There is a recommended slack amount for every application along with a tension value. Get to know your engine and the required slack in the timing chain and check it. Never assume that this is a no brainer item that will last forever. Veteran engine builders know better.
5. Fuel Pump Woes
With many of the current motors we run in the lower compression and rpm ranges, such as the crate motors, it has been said that they can run on pump gas just fine. That may be true for the ignition of the air/fuel mixture, but most pump fuels nowadays run a combination of gasoline and ethanol.
Up to 15 percent ethanol is used to help reduce the amount of petroleum we need as a nation. That's just fine for the economy, but for our racing engines and fuel delivery systems, it sucks. The introduction of ethanol to pump gas has caused numerous problems with racing applications.
Seals and glues that hold, for example the fuel filter element, are eroded away by ethanol. Corrosion occurs and seals disappear and the problems are sometimes hard to find. We know that some money can be saved by using pump gas, but in the long run, using pure gasoline racing fuels could prevent lots of headaches.
If you must run pump gas, consult with your engine builder or search the various engine parts and carburetor suppliers to find ethanol resistant products that will eliminate the problems caused by erosion and corrosion.
These oil line ends are a good example of the kinds you must use in your race motor. These
6. Plumbing the Oil Lines
For dry-sump motors, there is an accepted method for plumbing the motor that can help prevent very expensive problems. These simple but effective rules will possibly save you from a blown motor.
Always place your oil filter last in the line of flow back to the motor. Always replace the line between the filter and the motor if a failure in the motor occurs.
Always run the oil through the oil cooler into the bottom and out the top. This prevents air from being trapped and/or mixed with the oil in the lines.
Always use high-flow hose ends. Some ends are made with sharp 90-degree bends and are fine for hot rod applications where the oil flow rate is relatively low. For high-flow applications like in your race motor, use the ends that are meant for that.
Always use high strength and quality hose for the return line from the reservoir tank to the oil pump. This line is in suction and a weak hose can collapse causing a loss of oil volume and pressure that will guarantee a catastrophic engine failure.
Maintaining proper coolant temperature is not necessarily a function of radiator size or t
7. Water Flow Rate Regulation
The speed that the coolant flows through the engine and radiator is critical to how many BTU's of heat is absorbed and then removed. A flow that is too slow might cause a high retention of heat just as a flow that is too high might not allow proper removal of heat by the radiator.
Sizing the water pump pulley is one way to control the flow rate of the coolant. Passenger car pulleys are designed to flow efficiently in the lower rpm ranges that those cars experience. For racing applications where our engine speeds are greater, we need to use a larger-diameter pulley on the pump to reduce the rpm of the pump to flow the coolant slower.
A good set of temperature gauges will help you keep track of the coolant and oil temperatu
Reducers can be installed under the outlet where the radiator hose connects to the engine to regulate the flow rate of the coolant. If your coolant temperature is either too cold or too hot, these simple and cheap discs with various-sized holes could help tune your coolant temperatures.
The ratio between the pedal movement and the throttle opening must be sufficient to allow
8. Fuel Line and Filter
The fuel lines and filter are low-cost items that should be replaced maybe twice a year. The use of pump fuel can soften the glue that holds the filter element in place and allow the fuel to bypass the element meaning trash and debris could make its way to the carburetor.
When using mechanical engine mounted fuel pumps, the fuel line is in suction. An older weak line could partially collapse and cause fuel starvation problems. The engine will run rough or die and while we are frantically searching for an electrical or other problem, the fuel lines typically go unnoticed.
Visually check the throttle butterflys for full open position when the pedal is fully pres
9. Full Throttle Check
Periodically check that your throttle is going full open when the gas pedal is fully extended. Always use a throttle stop under the pedal to prevent bending the throttle linkage or the carburetor throttle shaft.
The ratio between the pedal motion and the degree of rotation of the throttle shaft needs to be correct to prevent the quick off-to-very-on syndrome. One of the driver aids is developing proper throttle control and that is very hard to do if there is little travel distance for the pedal. The pedal needs to travel from 21/2 to 3 inches at the ball of the foot.
10. Partial Throttle Testing
This is an advanced technique that some upper level engine builders perform. It's running the engine on the dyno using partial throttle all of the way up through the rpm range. The fuel mixture patterns can be much different with some carburetors when the throttle is only halfway open.
The reality is that many drivers only are able to use partial throttle due to lack of adequate traction on slick track surfaces. Many dirt races are won with the driver never using more than half throttle. So, how does your engine work under partial throttle conditions?
Next time you turn your motor over to the engine builder for dyno testing, ask him to run a partial throttle test. If he asks what that is, inform him. This simple test could help you discover fuel mixture problems before they cause a meltdown.