SPC

These are the variations of the 103 which I know but of course they may be others.

• Metallic red body, yellow base plate and interior, clear windows.
• Metallic red body, white base plate, yellow or cream interior, blue tinted windows.
• Metallic gold body, white base plate, yellow, cream or light blue interior, blue tinted windows.
• Prototype : yellow resin body.

It seems that the base plate has been modified where the number 103 is. A raised section usually indicates that something has been erased.

Spectrum Patrol Car (SPC) A nice model of the futuristic patrol car. For some reason Dinky fitted the car with 'jet engine sound'. Push the model down as you move it along and it makes a screeching noise. A silly idea - especially as the car made no such noise on t.v. A gimmick that could have been left out. I would have preferred opening doors. It says 'first again' on the box - it was probably the last time it was used too. Still, luckily the gimmick doesn't impair the car's appearance - unlike a similar treatment applied to the UFO Straker car... There must have been someone at Dinky who made a habit of taking a perfectly good model and spoiling it with gimmicks or peculiar paint finishes. As you can see in the picture, boxes started out simple and got rather large in later years.   (1968-1974)   First version have decal and relief on the door, second have decal without relief. After they are only stickers like other Dinky. Raised Roundel on door for decal - No Raised Roundel The one with the transfer Spectrum logo is the earliest. The other logo is not raised, it is thicker because it is a paper sticker. These stickers were introduced 1970 - 1971.

The two types of logos applied to the SPC.

The two types of wheels fitted to the SPC.

Having dissected 2 of these so far I was amazed to find that the "pinions", that is the small gears (2) at the center of the larger steel gear wheels, were made either of brass or mazak and on one of them the meshing wheel had cut a groove right around it.

The mechanism is purely there to make a noise. When you press the back down against the suspension the gear wheel on the axle (1) engages on the aformentioned pinion (2) and causes it to turn. The larger gear attached to this pinion turns the shaft on which is mounted the pressed steel flywheel (3). After it spun up to speed and the pressure on the back axle is released the flywheel spins freely and a spring steel "clicker", which rests against the pinion on the flywheel shaft, makes the whining noise. Amplified by the white plastic soundbox to which it's rivetted.
Replacing these pinions is the only way to fix this mechanism. If you can find a suitable replacement gear wheel they are a loose fit on the shafts and could be substituted, but a replacement gear with pinion would need to be the same diameter. Wheels might be found in any old fiction motor but since modern ones are nearly all plastic and old one are getting collectable it could be difficult. I know because I tried.
I eventually had to make replacements, fortunately I've done a little clock making so its not as difficult for me. I cut mine from brass using a dividing head on a milling machine. Thinking about it though, replacement gears and pinions may be found in an old clock. An alarm clock may suit as they tend to "cheap and cheerful" with more simply made gears.
I found that the number of teeth on the gears isn't as important as getting the right diameter, they have to mesh without binding.
The mechanism can be opened up by bending the tags (4) on the rectangular enclosure but it needs to be "unrivetted" (5) from the base plate.
Sorry to be so wordy but I hope this helps.
I've added some pics to this thread in the hopes that it clarifies the situation. The numbers in brackets refer to the pics