| Funnily enough Antonye, i disagree with you there.
On inline fours there are really only two firing orders 1243, of 1342. Either way, the pistons are paired, 1 and 4, 2 and 3.
On each pair one being on the firing stroke the other on the exhaust, and so on.
So in theory they could pair the firing strokes up, outside two, inside two...... etc |