Hoi,
Op een Amerikaans forum las ik het onderstaande bericht over de 123 onsteking. Daar had ik nog nooit van gehoord. Zelf heb ik ooit een 144 met B20A gehad waar een 123 op gemonteerd was, echt onder de indruk kwa verschil met een oud systeem was ik niet. Kan dat verhaal uit de USA een verklaring daarvoor zijn?
Groet,
Mathieu.
I wrote about the 123 on a B20B. The problem is that the engine is set up for vacuum retard, and the 123 is set up for vacuum advance. When you put the two together you get a really screwed up car. I talked to 123 and they insisted that vacuum retard was a US-only thing which is simply not true. It's all B20Bs worldwide.
When I say "the engine is set up for vacuum retard", that means the vacuum port on the manifold is on the engine side of the throttle flap, so high vacuum at idle. The high vacuum retards the timing. Then when you punch the throttle the vacuum drops and the timing pops forward.
Vacuum advance works just the opposite. The port is on the air cleaner side of the flap, so at idle there is no vacuum. When you punch the throttle the vacuum level jumps up and advances the timing.
When you mix the two, punching the throttle causes the timing to retard which is exactly the opposite of what you want.
I ended up swapping ports around to connect the 123 distributor to a before-the-throttle-flap port. I don't know if it can be done on all models, but was possible on the B20E without having to drill and tap a hole.
123 was completely uninterested in acknowledging the issue, let alone fix it. Very disappointing
