03-05-2021, 01:01 AM
Magnetic exh vaves are generally of XB steel or lesser. This was commonly used in many makes until late 50s. Burned valves and grinds were commonplace. The subsequent valves usually go the life of the car, 200,000 miles plus withut attention. The non magnetic valves, unless two piece, expand more when hot.
Extensive valve grinding is now frowned upon. If to correct the valve it unnecessarily wears the seat. Also forms a step on the valve. Seats can be tidied with a scrap valve, preferably refaced. If the valve has been refaced without chatter and with fine stone just a very slight lap then required. All been covered extensively but takes time to find.
Extensive valve grinding is now frowned upon. If to correct the valve it unnecessarily wears the seat. Also forms a step on the valve. Seats can be tidied with a scrap valve, preferably refaced. If the valve has been refaced without chatter and with fine stone just a very slight lap then required. All been covered extensively but takes time to find.