1965-1969 Chevrolet Corvair Troubleshooting
The second generation of Corvair with an improved suspension and new body style was released in 1965. It's air-cooled, rear engine design is similar to that of a Volkswagen, or Porsche.
Engine Idles Rough
A rough idle is usually caused by one or more of the following factors: poor compression, improper adjustment of the idle mixture and/or speed, or improper ignition. In the case of poor compression preforming a leakdown test is recommended to determine the locations of compression loss. Before checking the timing make sure your spark plugs, and wires are in good condition and not damaged or fouled.
Engine "Runs On" (Dieseling)
If your engine runs on after being shut off, then it is overheating! This is extremely bad for air-cooled cars such as the Corvair and can drastically decrease engine life. This is usually caused by the timing being too far advanced, or the mixture being too lean. You can learn to adjust your timing here. Usually when the mixture on the Corvair becomes too lean it indicates low fuel pressure(check the pump, and the filter), or that the carburators are clogged and thus must be rebuilt. it is possible however that the idle mixture adjustments are just too low, but this is less likely.
Short crisp clicks are often caused by maladjusted hydraulic lifters. however, this noise is often confused with exhaust leaks, which have a longer duration, or possible internal noises. by using a short hose with your ear at one end, try to isolate the location of the noise to make sure its the lifters before proceeding.
Clunking or Knocking
Heavy, loud, and/or hollow knocking coming from the engine is bad. This usually indicates a bad rod bearing, main bearing, or other internal problem, time for a rebuild.
Backfiring is usually caused by one of two things. The most common reason is that there is an exhaust leak. While under each side of the car listen for short bursts of air escaping around the exhaust manifold joints. Backfiring can also happen do to improper carburetor adjustments or, inadequate back-pressure.
Engine Will Not Start
This can be caused by a large variety of issues and can take some time to diagnose, even more so if your corvair is new to you. To diagnose the problem carefully make sure each system is operating as it should:
If the engine turns over, but will not fire, or does not fire on all cylinders, the first area to check is the ignition system.
If your coil is not receiving power, no ignition will occur. Check with a multimeter that with the key in the 'ON' position the coil is receiving 12-14 volts.
Spark Plug Issues
Foul or improperly gaped spark plugs can cause a weak spark. remove each spark plug and inspect its condition. if fouled or damaged, replace them.
Fuel Delivery Problems
If there are no Ignition Problems, and the engine still will not start, but does turn over, then there is possibly a fuel delivery problem. For adjusting your carburetors follow this guide.
The first place to check when a fuel delivery problem is suspected is the fuel filter itself.
Having the idle speed set too low will not provide enough fuel for the engine to keep itself running.
Having the proper air to fuel ratio is important for smooth and quiet operation.
If the carburetors do not provide equal fuel to each side of the engine, it will cause it to run rough, or not at all.
Internal Carburetor Contamination
Over time sediment from the gas tank builds up in the carburetors and lead to uneven running or clogged fuel passageways and jets. When this occurs, then it is time to rebuild them.
Valve Train Issues
The Corvair has hydraulic lifters, which eliminates the necessity for frequent valve adjustments, however, periodic adjustments should still be made.
Steering Is Loose
If your steering is loose, and all the related bushings are in good condition, then it is time to adjust the steering box lash.