Re: Broke exshaust valve afr 220 sbf heads
I don't see any indication of valves hitting pistons. That to me is the #1 cause for valves breaking. Fatigue ( old) is the #2 cause . "Material flaw" failure is very rare these days. I broke some "stock" Boss 302 exhaust valves 40+ years ago, but never a stainless unless it hit something first.
Tough for me to suggest anything else since the valve isn't "old" and it didn't hit anything before it broke ( from your pictures). AFR uses high quality parts , not junk like PCE. Sorry I couldn't help more.
Experimental Ford parts collector.
Last edited by GT350HR; 11-08-2017 at 12:17 PM.