Check valve seals on oil-eating SuperBee

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This article was published 27/06/2014 (4455 days ago), so information in it may no longer be current.

Question: I recently bought a custom car, a 1970 SuperBee, and plan on driving it in the summer on nice days and to car shows. It was working fine till I gave it a tune-up with new spark plugs and plug wires, and installed a chrome air cleaner and aluminum valve covers. The car suddenly started using oil, although it doesn’t show any real smoke out of the tailpipe unless I accelerate hard. Could I have done something wrong when installing the spark plugs or is something else causing the car to use oil?

Answer: You don’t mention what engine you have in your car, but most of these came with either a 383 or 440 cubic-inch V-8 engine. There could be several things that could cause one of these engines to suddenly start using oil, so let’s look at the more common ones. First, I would check the valve seals on the intake and exhaust valves. I suspect this vehicle may have been sitting in storage for a long time or driven very little. Rubber parts harden with age and the valve seals may have hardened and broken when you started driving the vehicle. This lets oil run down the valve guides into the intake manifold and be burned in the engine. Usually, this will show up as a puff of smoke when starting the engine after it has sat overnight. Replacing the valve seals is not a difficult job and can be done without removing the cylinder heads. Compressed air is blown into the cylinders through the spark plug hole to hold the valves in position while the valve springs are removed and seals replaced.

While the valve covers are off to check the valve seals, take a look at the PCV (positive crankcase ventilation) valve opening in the valve cover. There should be a metal shield inside the valve cover so oil cannot be sprayed directly at the PCV valve. Many aftermarket valve covers didn’t have a shield and the PCV valve would suck oil directly into the engine intake. This could cause high oil consumption.

Broken piston rings could also cause high oil consumption. This is a high-compresion engine and it needs high-octane fuel. If the ignition timing is advanced too far, it can cause engine pinging which can break piston rings. You can test the condition of the rings with a cylinder-leakage test, which measures the amount of air leaking from each cylinder. This is a better test than a compression test, as oil in the cylinder can sometimes cause misleading readings on a compression test.

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