Recently at a swap meet I picked up a box labelled as 318 marine parts, it included a rotor that had a wider contact at the spark-end than I'm used to seeing. Here's a pic:
I understand that marine engines sometimes or mostly have the crank turning the opposite way vs how they turn in a car. But I'm wondering about that wide contact - can someone tell me the theory behind it? Does the marine 318 operate over a wider spark advance curve - and hence would need the wider contact to insure the spark can jump from rotor to post? I thought it would be cool to put that rotor in my car (I have small block 318) but the shaft end design is totally different, it won't fit. But my primary question is - what is the theory behind the wider contact ?
I understand that marine engines sometimes or mostly have the crank turning the opposite way vs how they turn in a car. But I'm wondering about that wide contact - can someone tell me the theory behind it? Does the marine 318 operate over a wider spark advance curve - and hence would need the wider contact to insure the spark can jump from rotor to post? I thought it would be cool to put that rotor in my car (I have small block 318) but the shaft end design is totally different, it won't fit. But my primary question is - what is the theory behind the wider contact ?