krede Posted February 7, 2009 Report Share Posted February 7, 2009 Right... I took my head apart last weekend (Cylinder head that is ) Valves, guides and seats doesn't look half bad.. so I planned not to have anything ground. Now.. the normal procedure as I have learned it(on trucks mostly), would be to get the valves settled in with a bit of grinding paste.(which we also used to do after re grinding the valves /seats) However.. most places this is referred to as "lapping" the valves... and In my manual it specifically states that the valves of the N9Txx are NOT to be lapped.. So.. what to do?.. and if this indeed is the case.. whats up with that? Quote Link to comment Share on other sites More sharing options...
Bean Posted February 8, 2009 Report Share Posted February 8, 2009 I too thought valve lapping was a matter of course after a valve job. Are the seats and the valves still in good shape? (Seats still have the 3 angle valve grind?) It might be tempting to have them redone in a 5-angle profile - most shops here that can do it charge the same for 5 angle as the 3 angle. Once recut then there may not be a need for lapping - or maybe because it's a stock 3 angle they suggest no lapping... Dunno - be curious what others think / know. Rabin Quote Link to comment Share on other sites More sharing options...
Johnny Posted February 9, 2009 Report Share Posted February 9, 2009 Perhaps the exhaust-valves have stellite-coating? Quote Link to comment Share on other sites More sharing options...
V-M Posted February 9, 2009 Report Share Posted February 9, 2009 I have machined both sides (head and valve) and after that done lapping for all valves. I'm sure at after 100tkm there is no coating existing anyway If there eaven existed coating. I think modern angles is round instead of 3 or 5 angles. V-M Quote Link to comment Share on other sites More sharing options...
krede Posted February 13, 2009 Author Report Share Posted February 13, 2009 I have machined both sides (head and valve) and after that done lapping for all valves. I'm sure at after 100tkm there is no coating existing anyway If there eaven existed coating. I think modern angles is round instead of 3 or 5 angles. V-M So in your opinion it is fully acceptable to "lap" the valves ? Quote Link to comment Share on other sites More sharing options...
V-M Posted February 16, 2009 Report Share Posted February 16, 2009 So in your opinion it is fully acceptable to "lap" the valves ? Yes V-M Quote Link to comment Share on other sites More sharing options...
bryancohnracing Posted February 18, 2009 Report Share Posted February 18, 2009 I would agree that it would ok to lap the valves. The stellite coating would be long gone I would think... Bryan Quote Link to comment Share on other sites More sharing options...
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