Back Cutting Exhaust Valves. Corresponding exhaust valve has a thicker margin to resist higher temperatures and a generous radius on the bottom to encourage exit flow around the valve. Intake valve (left) has a 30° back cut above the seat and a thin margin with a sharp edge on the bottom to discourage inlet tract reversion. Easy upgrades if you know they exist! Cut it back until it comes within 0.030 of the witness mark with. My opinion of modding intake & exhaust valves for performance and how i do it. Usually steel valves like a 12* back angle have more reverse flow than a ti valve with a 25* back angle and back cutting the 12*. I back cut all my exhaust valves but made sure they had almost a sharp edge on the face to prevent back flow Start with a 22 deg back cut if you don't have access to a bench. Short overview of areas to add back cuts to the valves to enhance low lift flow.
from www.dreamstime.com
Corresponding exhaust valve has a thicker margin to resist higher temperatures and a generous radius on the bottom to encourage exit flow around the valve. Cut it back until it comes within 0.030 of the witness mark with. I back cut all my exhaust valves but made sure they had almost a sharp edge on the face to prevent back flow My opinion of modding intake & exhaust valves for performance and how i do it. Easy upgrades if you know they exist! Intake valve (left) has a 30° back cut above the seat and a thin margin with a sharp edge on the bottom to discourage inlet tract reversion. Usually steel valves like a 12* back angle have more reverse flow than a ti valve with a 25* back angle and back cutting the 12*. Start with a 22 deg back cut if you don't have access to a bench. Short overview of areas to add back cuts to the valves to enhance low lift flow.
Cutoff Valve. Valve Shutoff and Control Valves Stock Photo Image
Back Cutting Exhaust Valves Intake valve (left) has a 30° back cut above the seat and a thin margin with a sharp edge on the bottom to discourage inlet tract reversion. Cut it back until it comes within 0.030 of the witness mark with. Start with a 22 deg back cut if you don't have access to a bench. Usually steel valves like a 12* back angle have more reverse flow than a ti valve with a 25* back angle and back cutting the 12*. Corresponding exhaust valve has a thicker margin to resist higher temperatures and a generous radius on the bottom to encourage exit flow around the valve. Short overview of areas to add back cuts to the valves to enhance low lift flow. My opinion of modding intake & exhaust valves for performance and how i do it. Intake valve (left) has a 30° back cut above the seat and a thin margin with a sharp edge on the bottom to discourage inlet tract reversion. I back cut all my exhaust valves but made sure they had almost a sharp edge on the face to prevent back flow Easy upgrades if you know they exist!
