pics of the 72 as promised but I have questions Options

[superdad88]

Ok here are the pics of the car that I am going to buy. I worked on getting it running and I believe I think I know what's wrong with it.

I wasnt getting any spark to the spark plugs. So I traced it all the way back to the MSD. I believe the MSD is bad but wanted to ask you guys for sure before I go and spend 300 bucks.

There is a gold box to the right of the MSD, not sure what this is. I did check the transformer and I am getting voltage from there. I checked the MSD as per their website and from what I can tell its not providing spark.

But what is the gold box? Wanted to make sure it might be something simple and I am missing it before I spent the 300 bucks.

[SLITS]

With a points / coil system, the points open to collapse the field in the coil to produce a spark to the plug. Points wear, corrode, pit, closing the gap set and decreasing the time for saturation of the secondary winding in the coil .... known as dwell. Decreased dwell time ... decreased spark energy. This wear also changes the timing of the engine.

Points replacement ... cheap so to speak:

Two types ... magnetic (Hall effect) and optical triggers .... The magnetic ones have magnets embedded in a device that goes over the point cam of the dizzy with a module that "senses" the passing of the magnets and causes collapse of the secondary coil windings, producing a spark.

Optical is a light beam between two LEDs. Slots in the trigger wheel allow the light to pass, producing a trigger to collapse the secondary windings in the coil.

Both systems produce maximum dwell time for saturation of the coil = best spark energy.

The optical systems generally have a trigger box, which is nothing more than a capacitor that charges rapidly. When triggered, it shoots more stable voltage to the coil than a conventional system, supposedly insuring a maximum spark energy to the plugs.

The MSD, Crane Hy-Fire, and I don't remember the rest of them are basically the same .... They trigger a coil or a transformer (Porsche CDI is a transformer ... the CDI unit shoots 400 Volts to the "coil" which is why they won't work with a standard coil). High energy coils are used with these systems for hotter spark. A conventional coil can overheat and explode if fed to much voltage.

So, in this case, the PO was using an optical trigger to trigger the MSD which fires the coil ... coil is probably matched to the MSD for higher spark energy ... actually just redundancy as the MSD could have been triggered with points (and all the associated problems with points ... variable dwell, incorrect timing due to wear).

If the Gold box were hooked directly to a "standard" coil or a "hot" coil, the system would produce spark, reliably without varying dwell or timing as there is nothing to wear.

Oh well .... more coffee. Google Crane XR700 and you will find installation instructions for it. Pretty simple.