A&Q about 350Z
Q:
i'm in the middle of rebuilding the 9a i'm going to fit to my mk1, but the exhaust valves have hard grey brown deposites on the back like you'd see on spark plugs. can i scrape this off and re-grind the valves or do i need new valves.
i have scraped one and there are small surface cracks which will be due to overheating, which i think is because of the build up. are my valves scrap?
A:
Cracks in engine parts are never good dude...