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Classic/Antique Car Repair/No engine compression

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Expert: - 12/14/2008


Question
I have a 33 Pontiac straight 8 all cylinders but one have good compress. That one has no compression. Car set for about 2 years but I have run the engine 3 times in 4 days.A just deciieded to check compression All have about 60 LBS PSI. What are my options. Thanks

Answer
That sweet old Pontiac 8 was about the smoothes running engine on the road in it's day. That became a problem because when one cylinder dropped it was almost not noticeable unless listening close to the exhaust. Well here is how I would go on from here. I would do the compression test over again but this time add one or two table spoons of engine oil to each cylinder before taking the compression. Do this one cylinder at a time with all the spark plugs out. On the cylinder with zero compression if the compression comes up it indicates bad piston rings. If the compression stays low then you are looking at a hole in a piston or a bad valve. However if there was a hole in a piston there should be a puffing out of the oil fill cap and road draft tube when the engine is running. Either way then it is time to yank off the cylinder head and do a visual inspection and repair what ever you found.
Good luck.
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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