Install the valve retainer. NOTE: Before installing valve retainers and valve cotters, make sure both the shape of valve retainers and the color of valve cotters. If you have SILVER cotters, you must use the valve retainers which have the flat shape of the round. If you have BLACK cotters, you must use the tapered shape of the round as shown. Do not mix SILVER and BLACK cotters. | Surely install with a SILVER cotter Surely install with a BLACK cotter