0
Modern vehicle ignition systems use a negative ground system.
The reason some older vehicles used a positive ground system was because their manufacturers did not realize that metal erosion caused by sparking causes the center electrodes of the engine's spark plugs to be eaten away by the sparks if that electrode is connected to the negative side of the ignition coil's high tension output.
Such erosion can quickly make the spark-gap too large, causing late (aka "retarded") ignition problems which can seriously reduce the power output of the engine.
So, when using a positive ground system: a) the spark plugs had to have their spark-gaps adjusted every one or two thousand miles and b) the lifetime of the plugs was only around 5,000 miles or less.
Explanation
It is a fact of physics that, after millions of sparks, due to metal erosion there will be less metal on the electrode that is connected to the negative side of a dc (direct current) ignition coil.
So the center electrode of a spark plug will not erode away due to sparking if it is connected to the positive side of the ignition coil's high tension circuit and will erode away if is connected to the negative side.
As the spark plug's outer casing is much larger in area than its center electrode, if it is connected to the negative side of the ignition coil's high tension output, the erosion of the outer casing caused by sparking is hardly noticeable and this fact has the additional benefit that the spark-gaps of the plugs hardly ever need to be adjusted during their lifetime which, nowadays, can be well over 20,000 miles.
Add your answer:
Earn +20 pts
Does a 2002 Oldsmobile have a positive or negative ground system?
The system is negative ground.
Is a 1947 Oldsmobile a positive or negative ground system?
it has a negative ground system.
Is your 1996 suburban battery a positive or negative ground?
The Suburban has a negative ground system.
What are the makes of vehicles with negative ground system?
Most all vehicles built today have a negative ground system, and have had for decades.
Which terminal of battery is grounded in vehicles and why?
Negative terminal is grounded to the vehicle. Because the system is a negative ground system. Electricity will not flow unless it has a path to ground.
Where does the negative battery terminal go on the starter of a 1986 Monte Carlo?
The negative terminal does not go to the starter on a negative ground system. The negative terminal goes to ground.
What is the 1966 Volkswagen voltage system?
The original 1966 stock electrical system was 6 volt negative ground. In 1967 they went to 12 volt negative ground.
Is the battery on a 1983 380sl a positive ground?
I doubt it but I am not 100% sure. It is unlikely in 1983 BMW was using a positive ground system. You can easily find out. Trace the negative battery cable and see where it goes. It is is attached to ground then it is a negative ground system.
Is red positive or negative on a battery?
red is positive on a negative ground system
How can you tell if your Massey Ferguson 35 is positive or negative earth?
The quickest and best way is to look at the battery. If your positive cable (+) is going to the frame or body, positive ground. If the negative (-) goes to the frame or body, negative ground. I believe that a MF 35 is a neg ground system but use the check from above.
Does the farmall A have a positive ground electrical system?
Yes, this tractor has a positive ground system. It may have been retrofitted to 12 volt negative ground over the years though.
How do you know if a car has a negative or positive grounded battery?
Find the cable that is connected directly to the frame or sub-frame of the car. If it is red, then Positive is ground; If it is black, then Negative is ground. More than likely (but not in all cases) the electrical system is Negative ground.
