Classic/Antique Car Repair/mercedes point gap

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Expert: - 12/5/2007


Question
i have a 1973 mercedes 450sl. could you please tell me what the points gap on. also this car is not hiting on the number 4 and 8 cylinders although the plugs are firing. you can take the 4 and 8 wires off at the cap and it does not affect the run of the motor. thank you very much,Jason

Answer
According to MB the points are gapped using a dwell meter at 30 to 34 degrees. However this translates to .016" with a feeler gage. As far as number 4 and number 8 not firing this could be a crack in the distributor cap as 4 and 8 are right next to each other. The other possibility is that the two wires being next to each other have gotten switched. The firing order is going clockwise around the cap starting with number one is 1-5-4-8-6-3-7-2. If this is not the problem I would suggest starting with a compression test to make sure that the engine, valves, and rings are in good shape. If the compression test is ok then look for vacuum leaks, bad injectors and the usual stuff.
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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