My '89 Ford 460 engine was recently diagnosed with low compression on a couple of cylinders and found to be burned valves. The mechanic who I'm helping, pointed out to me that the air pumps that inject air into the exhaust headers, as part of a pollution control system, were not working as the pulley belt had been removed. To my knowledge, the vehicle has been driven about 12,000 miles without the air pumps working. The question that is raised is, does the injected air into the exhaust headers, which enters at about two inches along the header from the engine block, serve to cool the valves in any way? In other words, would the air pumps not working have caused the burned exhaust valves?
Thanks; Barry