I. Ignition System:
* Spark Plugs: Use AC Delco #R45TS or equivalent (check a reputable parts supplier's catalog for cross-references). The correct heat range is crucial; using the wrong heat range can lead to fouling or pre-ignition. Gap should be set to 0.035" - 0.040". Replace all plugs simultaneously.
* Distributor Cap and Rotor: Inspect for cracks, carbon tracking, or corrosion. Replace if necessary. Make sure the rotor spins freely and the cap contacts are clean and firm.
* Ignition Points (if equipped): If your car still uses points, they will likely require adjustment. The dwell angle needs to be correct (check your Oldsmobile shop manual for the specific specification). Points should be replaced periodically (every 10,000-15,000 miles or as needed). Consider upgrading to an electronic ignition system for improved reliability and performance.
* Ignition Coil: Inspect for cracks or damage. A weak coil can significantly reduce performance.
* Ignition Wiring: Inspect all high-voltage wiring for cracks, fraying, or damage. Replace any suspect wires.
II. Carburetor:
* Carburetor Cleaning: This is often the most critical aspect of a tune-up. A thorough cleaning is essential, paying close attention to jets, passages, and the float level. Consider a professional carburetor rebuild if you lack experience.
* Fuel Filter: Replace the fuel filter.
* Choke Operation: Ensure the choke is operating correctly. A faulty choke can lead to poor starting and running issues.
* Idle Speed and Mixture: Once the carburetor is cleaned and adjusted, the idle speed and mixture need to be adjusted according to the shop manual. This is best done with a vacuum gauge to ensure proper mixture.
III. Valves and Valve Train:
* Valve Adjustment: Hydraulic lifters were introduced in later years on the 371, but some 57 models might still have mechanical lifters. Check your shop manual to determine your lifter type and adjust valve lash if necessary. This is a more advanced procedure.
* Spark Plug Wires: Replace if necessary and route them correctly to prevent cross-firing.
IV. Other Considerations:
* Air Filter: Replace the air filter element.
* Timing: Set the ignition timing according to the specifications in your shop manual. This requires a timing light.
V. Resources:
* Oldsmobile Shop Manual: This is the single most valuable resource for accurate specifications and procedures. A reproduction manual can be found online from various classic car parts suppliers.
* Online Forums: Online forums dedicated to classic Oldsmobiles are excellent sources of information and advice from experienced owners.
Disclaimer: This information is for general guidance only. Improperly performing any of these tasks can damage your engine. If you lack the experience, it is highly recommended to seek the assistance of a qualified mechanic specializing in classic cars. Incorrect timing or carburetor adjustment can lead to serious engine damage. Remember to always consult your owner's manual and/or a reputable shop manual for the correct specifications for your specific 1957 Oldsmobile 88 371ci.
