adjusting dwell angle w116 280s Euro

[PILOT MAN]

I am trying to adjust the dwell angle on a w116 280s Euro, with normal ignition, i.e. no icu, just point, condenser and coil setup. The problem is that i have to INCREASE the pionts gap to INCREASE the dwell reading?? To my understanding this should not be the case, shoul'nt a decrease in pionts gap increase the dwell angle?

when i adjust the dwell angle to 38 degrees, the pionts gap is app 0.023 inches, shoulnt it be more like 0.011?

when i adjust the dwell to 38 degrees the engine also pre ignites, when i make the pionts gap smaller, the dwell angle also becomes smaller i e to 30 degrees the car runs fine and does not pre ignite?

what causes this inverted way i e increase in pionts gap equals increase in dwell angle?

[PILOT MAN]

please i am struggling blind here.

[Arthur Dalton]

Dwell is inverse of gap.
The only thing I can think of where the gap and dwell both increase would be that the dwell meter is incorrect polarity.

[PILOT MAN]

Just to be certain, the green wire from the distrubutor(points wire) goes to the negative side of the coil? 12volt current from ignition switch goes to the positive side of the coil?

then i connect the positive side of the dwell meter to the positive side of the coil?

[250 Coupe]

The green clip goes to the coil post connected to the points, which should be the - side, and the other clip goes to ground and not the + post.

Michael

[Rick76]

There are a lot of M110's in wrecking yards now. Why not put a 1977 or newer distributor and module in and get rid of the points altogether. I picked up a couple of sets for $50 a set.

[Arthur Dalton]

From a 914 article:

The Cam angle, or dwell angle is the number of degrees through which the distributor cam rotates while the breaker points are closed. It is directly related to the breaker point gap. Decreasing the breaker point gap will increase the cam angle. If the cam angle is too small, the current will have insufficient time to pass though the primary winding of the ignition coil, and a weaker spark will result. If the cam angle is too great, the breaker points will not open far enough, they will tend to stick together, and misfiring will result. The best method of adjusting breaker points is by means of a dwell meter."


Figure 1:
914 Points

Figure 2:
Dwell Angle Reading
You usually hook up the dwell meter by attaching one lead to ground and the other to the negative terminal of the coil.

[PILOT MAN]

Thanx 250c, i had the dwell meter connected up wrongly. I connected the positive side of the dwell to the positive of the coil, and the negative of the dweel to the negative side of the coil.

i will adjust it correctly tonight, positive of dwell to negative of coil, and ground on dwell to body ground.