Pistons

[Robert Leigh]

Yes, it does matter which way round the pistons are fitted. The front marking exists in particular on split skirt pistons; they should be fitted so that on the power stroke the plain side is the opposite side of the block from the crank throw; this keeps the side thrust away from the split. I understand that the split is to reduce piston slap in the interest of quiet running (a relative term!). Long ago I did fit some pistons the wrong way round; it did not seem to make a big difference, but it was pointed out to me by the next person to dismantle the engine.
Robert Leigh