A Thank you very much for all the kind words. It's a pleasure helping as many people as we can. Well, while my answer wasn't a mistake, it could use further explanation. Here we go.
As you all have read, motor oil is currently in a state of decline when it comes to the wear-additive packages. The additive package is zinc dialkyl dithiophosphate (ZDDP), a combination of zinc and phosphorus. The main concern about this additive is the degradation of oxygen sensors and catalytic converters on our cars. As the engine wears and burns oil, either past the rings or from valve-guide wear, this mixture of additives coat the O2 and the converter. This is why the government has required passenger-car motor oil to reduce the additive package. Diesel oils still have this additive package to help prevent wear in the high-load contact areas like camshaft lobes and flat-tappets.
Years ago, I was told that you didn't want to run diesel-spec oils because they didn't have antifoaming agents and special additives to prevent oil thinning from gas dilution. Well, with the advent of high-speed (relative term when talking about diesel engines) light-truck diesel engines like the DuraMax, the oil has been hopped up. These engines see much higher engine speeds than the large, over-the-road diesel truck. Several years ago diesel oils began adding the antifoaming and -dilution agents to prevent these problems, and the Delo 400 even lists gasoline engines on its bottle.
Check the label on your favorite brand of diesel-specific oil and look for the CI-4 or CI-4 Plus markings. These oils have the ZDDP additive packages with the antifoaming and -thinning agents. We would, however, only use these oils in pre-catalytic and O2-sensed engines, or you may find yourself replacing converters and O2s to pass regular emissions tests. Sorry for the confusion and thank you for making me learn more about it.
What's That Smell?QI have questions about the fuel-vapor storage canister and its effect on performance. The car is a '78 Camaro with a stock 305 2bbl that I plan to drive occasionally as I build a 355 and generally improve everything about the car. I want to keep most of the emissions equipment functioning, if I can do so with little or no power loss. Currently I live in a county with no emissions testing, but I want to be as environmentally responsible as possible. The fuel-vapor line runs from the canister to a fitting on the intake that isn't present on the 4bbl intake I have. I have an Edelbrock Performer 1406 carb with no provision for a fuel-vapor return line. I plan to drill a carb spacer and plumb the vapor return line into it. Will this be a horsepower killer? I believe simply running two modern three-way cats will make this car's exhaust cleaner than it was when new. I want to avoid buying another carb if possible. Any ideas?DanVia e-mail
A Retaining emissions-control devices that do no harm to performance is a great idea. There is no reason to remove the vapor canister from your Camaro. The vapor canister has a charcoal bed that captures hydrocarbon vapors and stores them until they are purged on start-up. This canister is a vent for the fuel tank and also captures the fuel vapor from the heat-soaked carburetor when you shut the engine off. When you refire the engine, a ported vacuum signals the canister to see manifold vacuum. This is the port that you need to drill into the carb spacer. The canister is a very slight vacuum leak that doesn't affect the engine's performance, but keeps those annoying hydrocarbon vapors out of our atmosphere.