Most small-block rockers "check" between 1.40:1 and 1.47:1. The resulting number is theoretical gross valve lift. To verify the figures, either check the number with your cam-spec card or check the lift at the lifter and multiply the number by your rocker ratio. Don't be surprised if the numbers don't correspond. Compare this gross (zero lash) figure to your camshaft specifications. Manually turn the engine through one complete revolution. Next, install a dial indicator to read off the valvestem side of the rocker arm. To execute the plan, install one solid lifter on one camshaft lobe, then carefully tighten the rocker arm to zero lash. There are several solutions, and if you can't afford aftermarket roller rockers, do what racers in the past did (and NHRA Stock Eliminator racers still do): Index a bunch of rockers until you find 16 of them with the highest effective ratio that are relatively close to one another. Need more? Install a 50cc pump kit (commonly called a "REO" kit), available from any Holley distributor. Stack the cut diaphragm in conjunction with the standard diaphragm, and you'll realize a volume increase easily. Increase pump volume by cutting away the center of a standard accelerator-pump diaphragm. If the stumble persists, you might have to resort to a larger-volume accelerator pump. Employ the Holley "system," which revolves around larger pump shooters, as well as a fine-tuning of the pump cams. Solution: increase the shot of the accelerator pump. The throttle is wide open, the automatic transmission is placing a major load on the engine, and believe it or not, the carburetor is running out of fuel. This is a known as a hole in the fuel curve. Obviously, this seems legitimate because the car goes "waaahhhhhh," then falls flat on its face. Initially, you might diagnose the problem as simply too much carburetor. Many modern car engines use coil-on-plug ignition, which eliminates the need for spark plug wires.ĭiesel engines do not use spark plugs, and therefore do not use spark plug wires either.26 Cars equipped with a Holley carburetor and an automatic transmission are sometimes known to stumble just off idle. Some engines instead used multiple ignition coils (one for each pair of cylinders) built into a coil pack, eliminating the need for a distributor and coil wire. Some distributors have an ignition coil built inside them, eliminating the need for a separate coil wire, such as the High Energy Ignition (HEI) system used by General Motors in the 1970s and 1980s. A coil wire is of the same construction as a spark plug wire, but generally shorter and with different terminals. Older ignition systems with a separate ignition coil use a coil wire between the ignition coil and the distributor. Stainless steel wire wound as a coil in the lead with a resistance of about 1300 ohms/meter since 1980s.Compressed carbon powder as conductor in the lead to act as a resistor.Resistor in spark plug with copper conductor. To reduce radio frequency interference (RFI) produced by the spark being radiated by the wires, which may cause malfunction of sensitive electronic systems in modern vehicles or interfere with the car radio, various means in the spark plug and associated lead have been used over time to reduce the nuisance: There are dedicated spark plug wire pliers, tools designed for removing the terminal from a spark plug without damaging it. Each end of a spark plug wire has a metal terminal that clips onto the spark plug and distributor, coil, or magneto. Each lead contains only one wire, as the current does not return through the same lead, but through the earthed/grounded engine which is connected to the opposite battery terminal (negative terminal on modern engines). The wire from each spark plug is just long enough to reach the distributor, without excess. Printing on spark plug wires may include a brand name, insulation thickness (in millimeters), insulation material type, cylinder number, and conductor type (suppressor or solid wire). Dielectric grease can be used to improve insulation a small amount can be applied in the inside of the rubber boot at each end of each wire to help seal out moisture. The thick insulation prevents arcing from the cable to an earthed engine component. Spark plug wires have an outer insulation several times thicker than the conductor, made of a very flexible and heat-resistant material such as silicone or EPDM rubber. ( February 2023) ( Learn how and when to remove this template message) Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources in this section. This section needs additional citations for verification.
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