Posted 30 May 2004 - 08:16 PM
the a series, and some of the early a+ engines have a dizzy that has a clamp around the base, this clamp is then held onto the block with 2 bolts. these are handy, because you can remove the dizzy without affecting the timing.
the later a+ engines have a dizzy that is held in place by a sort of 'y' shaped clamp held in place by a single bolt. with this method if you take the dizzy out for any reason, make sure you put a mark on the block and the dizzy so you put it back in the same place it came from.
the 25d4 is the older a series dizzy, this was fitted up until the mid 70's i think, and then replaced with the 45d4. the quick way to tell the difference is the caps, the 25 cap is quite rounded, while the 45 cap is a lot squarer looking.
the later a+ dizzy's have wider drive lugs, compared with the 'a' series dizzys.