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Engine Install and Tuning Tips

Performance engine durability is dependent on several supporting systems including the cooling system, fuel delivery system, ignition system, and oiling system. If the support systems are not adequate, poor engine performance and possible engine failure could result.


OILING SYSTEM CONSIDERATIONS/COMMON PROBLEMS

  • Priming the oiling system before starting a new engine is crucial to engine life. This is important on initial start up of a new engine and if a used engine has not been run for extended periods of time.
  • Does the oil pan have adequate capacity? Most performance vehicles require a 7 qt minimum capacity. All engines will benefit from increased oil pan capacity.
  • Does the oil pan have proper oil control baffling for the vehicles braking, acceleration, and cornering capabilities? Road Race cars need oil control in four directions: braking, acceleration, LH cornering and RH cornering. Drag race cars need oil control in two directions, braking and acceleration. Baffles must be designed to keep oil over the pickup screen at all times.
  • Is the pickup screen the proper distance from the bottom of the oil pan? If the oil pickup screen is too close to the bottom of the oil pan, it can cause cavitation. If it is too far away, it will cause the pump to draw air and minimize lubrication capacity. The pickup screen should be located .250" to .375" from the bottom of the pan. Does the design of the screen on the pickup tube create restrictions? We have seen some pickup tube screen designs that restrict oil flow as much as 75%. Wire mesh is good. Perforated metal is usually restrictive. Measure the wire size and calculate the flow area. Most aftermarket screens have less flow area than stock screens.
  • If using a remote oil filter mount or oil cooler, make sure that all of the components are large enough to eliminate any restrictions to oil flow. Many Cobra replica kit cars use components that are too restrictive.
  • Undersized oil lines commonly restrict oil flow.
  • The more bends/turns in an oiling system, the more restrictions that are created.
  • Poorly designed remote filter mounts and adapters can create restrictions.
  • Be sure that the oil cooler flows enough oil to meet the engine's requirements.
  • Never reuse a used oil cooler. Debris gets trapped and cannot be cleaned out.
  • Poorly designed oil filters can cause a restriction.
  • Many oil systems only flow one way. Connecting the remote oil filter or oil cooler lines backwards can cause engine damage/failure.

IGNITION SYSTEM CONSIDERATIONS/COMMON PROBLEMS

  • The ignition system must deliver a properly timed spark. There are a lot of factors that determine when the spark should be delivered. The most common factors include: Compression ratio, fuel quality, fuel octane rating, combustion chamber design, engine operating temperature, power adders such as NOS or supercharger, inlet air temp, altitude, and load.
  • Avoid too much or too little timing for your engine combination.
  • Avoid hooking up the vacuum advance to intake manifold vacuum instead of ported vacuum.
  • Avoid inductive crossfire created by improper plug wire routing. Separate plug wires on cylinders that fire in sequence.
  • Improper timing can damage pistons, rod bearings, head gaskets, and many other engine parts.
  • Typical total mechanical advance timing at 4000 RPM for Ford Racing Performance Parts crate engines: 5.0L - 36° to 38°, 347/351 - 34° to 36°, 392/460/514 - 30° to 32°.

FUEL DELIVERY CONSIDERATIONS

  • Size of fuel pump, size of fuel line, fuel pump placement, fuel filter placement, fuel filter size, injector size, fuel rail size, fuel pressure, jet size, and baffling in the fuel tank.
  • Does the fuel system maintain full pressure at peak engine horsepower in high gear? Altitude, air temperature, and fuel characteristics including quality, specific gravity, and octane rating, will affect your jetting requirements. Engine efficiency and Brake Specific Fuel Consumption (BSFC) also have an effect. Here are some examples of a Holley 750 CFM 4V.



  • Jetting Jetting
    Octane Temp. Altitude Front Rear
    94 80 F 0 ft. 81 86
    Aviation 100LL 80 F 0 ft. 81 84
    110 Race 80 F 0 ft. 78 83
    94 80 F 3000 ft. 76 81
    94 80 F 6000 ft. 73 77
    94 40 F 0 ft. 84 89
    94 120 F 0 ft. 78 83

    As you can see by these examples, jet requirements can vary a lot depending on fuel, altitude, and temperature. Oxygenated fuels are available in some states and can dramatically affect your jetting requirements. Make sure you get your jetting correct. Aviation fuel is lighter and will require richening an engine in relationship to it's requirement with "pump gas." We have found in the dyno testing of our crate engines that 1 point richer on air/fuel ratio equals only a few percent less power. Running an engine as lean as possible produces the best power but also increases combustion temperatures and the chances of engine damage.

COMMON PROBLEMS WITH FUEL DELIVERY SYSTEMS.

  • Do not mount an EFI electric fuel pump so it has to draw fuel from the tank. This creates a negative pressure in the fuel line allowing the fuel to boil at a lower temperature.
  • The pump must be mounted in the tank or in a location so that it is gravity fed.
  • If the fuel rail is too small and you have large injectors, this can create a pulse in the fuel rail allowing fuel starvation on some cylinders.
  • Fuel should be pushed through the fuel filter. Pulling fuel through a filter can cause cavitation. If a filter is to be used on the inlet of a rail mounted fuel pump, a filter rating of 160 microns MINIMUM should be used.
  • It takes approx. 1/2LB of gasoline to support 1 HP. This is commonly referred to as a .5 BSFC. You should always err in the safe direction of larger when sizing your injectors and fuel pump

COOLING SYSTEM CONSIDERATIONS/COMMON PROBLEMS

  • Higher horsepower requires more cooling capacity.
  • When the fill point of the cooling system is not the highest point, air pockets are created. The air pockets then create hot spots, and the hot spots promote improper combustion. Which can cause engine failure.
  • Improper pulley size makes the fan and water pump turn too slow or too fast. Production water pumps are normally run at 20% over engine speed and do not perform well over 5000 engine RPM. Underdrive pulleys generally reduce water pump speed to 85% of engine RPM and may not provide enough water flow to cool the engine.
  • The radiator must have enough area to dissipate the heat being generated by the engine.
  • If the fan size is too small, it will not move enough air across the radiator so it can properly dissipate the heat being generated. Fan shrouds increase the effectiveness of the fan significantly.
  • Radiator location can affect airflow through the radiator at different vehicle speeds.

FLYWHEEL, CONVERTER AND TRANSMISSION PROBLEMS

  • Installing the wrong flywheel for the balance factor of the engine, will cause vibration and eventually damage the engine.
  • Wrong length input shaft or "stack up height" can force the crank forward and damage the engine thrust bearing.
  • Improperly installing the torque converter can force the crank forward damaging the engine thrust bearing. This is most commonly caused from not locating the torque convertor drain plug properly in the flexplate.
  • If the torque converter balloons, it can force the crank forward, damaging the engine thrust bearing and the transmission. Most high performance torque converters have anti-ballooning features.
  • Damage to the thrust bearing can happen in seconds!

MISCELLANEOUS PROBLEMS THAT CAN DAMAGE AN ENGINE

  • Nuts, bolts, washers or foreign materials dropped down the intake. We have seen this more than once.
  • Reusing an intake off an engine that had broken parts in a cylinder. The parts can get bounced up into the intake manifold, carburetor or air cleaner (pieces of piston, or piston rings etc.). When you put your used intake on your new engine and start it, the pieces are drawn in and damage your engine.
  • Bead blasting an EFI intake. You will NEVER get all the blasting media out. When the engine is started it draws the blasting media into the cylinders, destroying the engine.
  • Not properly torquing fasteners when installing new parts to your engine. Over torquing of the intake manifold bolts to cylinder head on 302 and 351W engines can cause head gasket sealing problems.
  • Distributor gears installed at the incorrect height and gears made of the wrong material. We have seen this a lot on remanufactured distributors as well as popular aftermarket manufacturers of distributor assemblies. Use cast iron gears for cast iron flat tappet cams, and steel gears for steel hydraulic roller cams.