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Classic/Antique Car Repair/Main bearing failure on 1946 Plymouth

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Expert: - 3/2/2010


Question
I have restored my 1946 Plymouth Coupe to original but keep having the reoccurring problem of main bearing failure. I know that it was problem but have they come up with any new advances i.e. phosfor bronze that might help

Answer
I am not sure that main bearing failure was any more of a problem on these engines as any other. This engine was the darling of the taxi fleet back in the day so it could not have been too bad. In the late 40's I was just entering the auto repair field. I would check the bore alignment of this engine and make sure that it is straight. Then I would look at all of the bearing clearances. If you are replacing the mains and setting them up tight and the rod bearings and cam bearings are looser then the oil will flow to the looser bearings and could actually cause the tight mains to starve for oil. The next thing is the weight of the oil. With bearings set up with minimal clearance running a heavy weight, 30 for instance, will also cause the bearings to run dry. Alignment and clearances are the solution.
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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