should I lap my valves in?

[clasabro]

Got the heads off (V8 Rover engine)valve seats look as if they should be lapped in but they look as if they may be self lapping valves that haven't properly. Are the seats case hardened so lapping is a no no? Exhaust valves have about 1mm wide seat slightly indented and then the whole seat is black and level accross with soft carbon.No sign of the buff had coating I expected. My mate with vintage BSA's blames unleaded petrol for the soot not sure I believe him.

[mrzigazaga]

Hi mate...Hopefully someone with a lot more know how will answer you but I'm sure that the 350i had hardened valve seats as the recommendation for unleaded was to retard the timing a tad..And it was reported that they would run better on unleaded and no additive was needed...Not the case with my 1982 280i which had leaded heads..And then recessed valves..

Not sure about the carbon thingy but if your mate rides a BSA then nick his oil filler cap as it should fit a Wedges fuel filler neck... ...Or was it Norton......