Classic/Antique Car Repair/exhaust backfire

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Expert: - 5/2/2009


Question
52 Chevy Pickup 216, Backfires in exhaust on acceleration.  Timing, points plugs
OK. Will engine additives help?  How do I adjust valve / lifter clearance.

Answer
Several things can cause this. Before I went to valve adjustments I would check the distributor cap and plug wires to make sure that I was not getting a cross fire on heavy load when the ignition system is putting out max voltages. Secondly I would run a compression test on the engine. There are adjusting screws on the rocker arms above the push rods. With the engine running and the valve cover off a feeler gage is inserted between the valve stem and the rocker and the adjusting screw turned until a drag is felt on the feeler gage. In my experience engine additives are for the most part marketed to make the person marketing them rich.
Brad

Classic/Antique Car Repair

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Brad Sears

Expertise

All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.

Experience

Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Publications
Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

Education/Credentials
More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

Awards and Honors
Moto Award winner. And much more.

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