When classic car expert Henry Olsen of Performance Motorsports in Millbrae, CA gets a vintage carburetor equipped vehicle in for service he has a well-tuned process to restore the power and drivability that the engine once had.
These engines, designed to run on leaded gasoline, must be tuned to perform on the oxygenated and unleaded gasoline of today. To get the information he needs to make diagnostic and service decisions, Olsen uses the 5-gas exhaust analyzer from Bridge Analyzers to measure CO, HC, NOx, CO2, and O2. These readings enable him to determine the engine's air/fuel mixture and, consequently, how efficiently the engine is burning the fuel.
HC (unburned hydrocarbon) readings from the analyzer guide the ignition spark advance settings. The CO2 reading is used as an indicator of combustion efficiency. NOx readings can determine if combustion temperatures are excessive, which can be related to over-advanced ignition spark timing and/or overly lean air/fuel mixture. Click here to read the full article from THE SHOP magazine where Olsen shares his diagnostic and service expertise for vintage engines operating without the constant control of today's closed loop engines.