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Classic/Antique Car Repair/1960 pontiac 389 catalina

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Expert: - 4/25/2011


Question
I have a 389 catalina that started tapping and backfiring through the carb. any sugestions

Answer
Sounds like it could be something in the valve train like a broken rocker or bent push rod on an exhaust valve that is letting trapped exhaust gas spit out the intake valve on that cylinder when it opens. Or it could be a bent intake valve. I would first take a compression test on the engine and see if here is one low cylinder. Then remove that valve cover and do a visual check of the valve action on that cylinder. If the visual is ok and there is a cylinder with low compression then it is time to take off the head. Now, did this start all of a sudden? let me know.

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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