Resto Basics: spark plug care

More on spark plugs
My recent series on spark plugs prompted a response from Sanford Danziger. He suggested some useful tips for maintenance that I omitted including:

When cleaning the spark plug recess prior to plug removal, a vacuum cleaner can be used if you don’t have access to compressed air.

Plastic food wrapper tabs can be used to mark plug wires if you don’t have access to a cable number set. Write the cylinder number on the tab and attach it to the plug wire.

Always change spark plugs in aluminum cylinder heads when the engine is cold. Removing plugs from a hot aluminum head runs the risk of damaging the threads.

Use die-electric grease for spark plug boots.

Mr. Danziger opined that cleaning the plugs is questionable as it may wear the insulator and alter the heat range. He favors replacing dirty spark plugs with new ones. While it is true that the maintenance procedures I described in Part III – “Spark Plug Maintenance” – have been generally precluded by high-energy ignition systems introduced in the mid-1970s, it remains good practice for cars with six-volt systems.

The typical voltage at the spark plug in six-volt systems is not sufficient to efficiently clean the plug, unless the car was driven under high-speed conditions to bring the plug to the upper part of its temperature range. Cleaning with a spark plug cleaner (a small media blaster) was the standard practice recommended by plug manufacturers in the days before high plug voltage eliminated its need. The limited exposure to the cleaning media will not alter the heat range as Mr. Danziger fears.

In addition to having a clean plug, the condition of the center electrode is key. It should have sharp edges. Typically, this condition can be obtained by a few passes with the point file. Sharp electrode edges, along with the proper point gap, encourage good spark propagation in low-energy ignition systems.

More on oil for old cars

Concerns persist in the collector vehicle hobby about oils to use for old cars. Several entrepreneurs are taking advantage of this concern to offer “solutions” for perceived and real issues. At the recent Cadillac LaSalle Club Grand National, a representative of the American Petroleum Institute (API) provided a presentation that essentially repeated what I provided in these pages last year.
To those who remain concerned about oil, knowledge and information is key. Detailed information is available on the internet at This Web site, sponsored by Chevron, provides editorial content and instructional courses that deliver lubricants- and coolants-related knowledge. The site is designed for individuals in the lubrication and maintenance markets that are interested in obtaining more information on relevant technologies, trends, issues and solutions. However, the depth of knowledge is an excellent resource for those hobbyists who want to get the facts. A few courses are free, but most carry a nominal charge for what are in-depth courses of a few hours each.

The site also contains informative articles pertinent to lubrication, as well as the re-launch of an industry icon, Lubrication magazine. These articles are topical and free of charge, offering insights into an industry that is ever-changing.

William C. “Bill” Anderson, P.E., has been involved with the automotive hobby for more than 30 years with experience ranging from hot rods, to sports cars, to sports car racing, and to restoration of vehicles from the 1930s through the `80s. He is an author, magazine editor, car show judge, and professional engineer. A member of several car clubs and a leader in some, through Anderson Automotive Enterprises he restores and appraises cars.


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